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Flow Measurement Handbook Industrial Designs Operating Principles Performance and Applications 2nd Edition Roger C. Baker
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Editor'sForeword
The McGraw-Hill Education Trade and Technology list has been designed to provide entry-level competencies in a wide range of occupations in the electrical and electronics fields. It consists of coordinated instructional materials designed especially for career-oriented students. A textbook, an experiments manual, and online resources support each major subject area covered in the series. All of these focus on theory, practice, applications, and experiences necessary for those preparing to enter technical careers.
There are two fundamental considerations in the preparation of a text like Digital Electronics: Principles and Applications: the needs for the learner and the needs of the employer. This text meets those needs in expert fashion. The authors and editors have drawn upon their broad teaching and technical experiences to accurately interpret and meet the needs of the student. The needs of business and industry have been identified through personal interviews, industry publications, government occupational trend reports, and reports by industry associations.
The processes used to produce and refine the series have been ongoing. Technological change is rapid, and the content has been revised to focus on current trends. Refinements in pedagogy have been defined and implemented based on classroom testing and feedback from students and instructors using the series. Every effort has
been made to offer the best possible learning materials. These include animated PowerPoint presentations, circuit files for simulation, a test generator with correlated test banks, dedicated websites for both students and instructors, and basic instrumentation labs. All of these are well coordinated and have been prepared by the author.
The widespread acceptance of Digital Electronics: Principles and Applications and the positive feedback from users confirm the basic soundness in content and design of all the components as well as their effectiveness as teaching and learning tools. Instructors will find the texts and manuals in each of the subject areas logically structured, well paced, and developed around a framework of modern objectives. Students will find the materials to be readable, lucidly illustrated, and interesting. They will also find a generous amount of self-study materials, review items, and examples to help them determine their own progress.
Both the initial and ongoing success of this text and others with the McGraw-Hill Trade and Technology list are due in large part to the wisdom and vision of Gordon Rockmaker, who was a magical combination of editor, writer, teacher, electrical engineer, and friend. The publisher and editor welcome comments and suggestions from instructors and students using this series.
Charles A. Schuler, Project Editor
CharlesASchuler,ProjectEditor
Preface
Digital Electronics: Principles and Applications, eighth edition, is an easy-to-read introductory text for students new to the field of digital electronics. Providing entry-level knowledge and skills for a wide range of occupations is the goal of this textbook and its ancillary materials. Prerequisites are general math and introductory electricity/electronics. Binary math, Boolean concepts, simple programming, and various codes are introduced and explained as needed. Concepts are connected to practical applications, and a systems approach is followed that reflects current practice in industry. Earlier editions of the text have been used successfully in a wide range of programs: electronic technology, electrical trades and apprenticeship training, computer repair, communications electronics, and computer science, to name a few. This concise and practical text can be used in any program needing a quick and readable overview of digital principles.
New to this Edition
Chapter 1
• Digital applications, including automotive fuel indicators, vehicle speed sensors, and engine control module.
• A new section on where digital circuit applications are used.
• Information on logic probe use in troubleshooting.
• A revised instruments section.
Chapter 2
• Subsection on applications of encoders and decoders.
Chapter 3
• Updated information on practical chips including lower voltage ICs.
• Expanded most self-test sections.
Chapter4
• Expanded several self-test sections.
• Revised material on data selectors.
Chapter 5
• Information on low-voltage ICs.
• Added many application assignments on interfacing.
Chapter 6
• Updated applications of the Gray code, including the shaft encoder, and new information on the quadrature encoder.
• Updated information on display technologies.
Chapter7
• Application of an R-S latch.
• A new detailed application of a latched encoderdecoder system.
Chapter 8
• Expanded self-test questions.
Chapter 10
• Expanded several self-tests.
• Updated binary subtraction section.
Chapter 11
• Updated overview of memory section.
• Updated nonvolatile read/write memory section
• Updated memory packaging section.
• Expanded bulk storage section, including more information on USB flash drives.
• Internet research topics.
Chapter 12
• Expanded self-test and critical thinking questions.
• Information on distance sensing with coverage of several sensor technologies.
• A DIY application demonstrating a distance sensor triggering the timed operation of a stepper motor.
Chapter 13
• Updated microcomputer section.
• Updated data transmission section.
Preface IX
• A revised microcontrollers section.
• Application of a microcontroller with photo input and servo motor output.
Chapter 14
• Expanded self-test questions.
Additional Resources
An Experiments Manual for Digital Electronics contains a comprehensive test, a variety of hands-on lab exercises and experiments, and additional problems for each chapter in the textbook.
The Online Learning Center (OLC) at www.mhhe. com/tokheim8e includes comprehensive Multisim files, keyed to circuits found in the eighth edition, and a Multisim primer (written by Patrick Hoppe of Gateway Technical College), which provides a tutorial on the software for new users. The Multisim program itself is not included on the
website, but the latest version, version 12, can be purchased through McGraw-Hill at a discount when you adopt this textbook. Visit www.mhhe.com/tokheim8e or contact your McGraw-Hill sales representative for more information.
The OLC also features chapter study resources, links to industry and association sites, and assignments and tests for students. Instructors can access the instructor side of the OLC to find a wide selection of information including:
• An Instructor's Manual that includes a list of the parts and equipment needed to perform lab experiments, learning outcomes for each chapter, answers to chapter review questions and problems, and more.
• PowerPoint presentations that correlate to all chapters and special PowerPoint presentations on breadboarding, soldering, circuit interrupters (GFCI and AFCI), and instrumentation.
• A test generator, EZ Test, which includes a test bank with questions for each chapter.
x Preface
cknowledgments
Thanks to family members Marshall, Rachael, Dan, Jack, Ben and Carrie for their help on this project. I would also like to thank the reviewers who helped evaluate the textbook; I am grateful for their time and expertise.
Mike Carter Mercedes-Benz Institute
Richard Fornes Apollo Career Center Adult Education
J. C.Morrow Hopkinsville Community College
Tom Neal Southern Crescent Technical College
Randy Owens State Fair Community College
Chrys Panayiotou Indian River State College
G. Albert Popson West Virginia Wesleyan College
Joseph Tront Virginia Tech
Mark Winans Central Texas College
Jillian Wooldridge Erie Institute of Technology
alkthrough
Digital Electronics: Principles and Applications, eighth edition, is designed for a first course in digital electronics. It provides a concise, modern, and practical approach that's suitable for a range of electricity and electronics
Digital Electronics
Learning Outcomes
Tflixchapter will hdpyo11m:
1·1 fdr1u1/y ,,...,,er;tl dwr.ic1eri<lk.'i of di,sir.d cin:uitsa>oppo o.J1o:m.1hP;dn:uil>. and;1n.1!oi; .<ii;11:11.•, :ind ide111if1· 1nc HIGH aml LOW portionsnfa<ligi1atw·.1vcform
1·2 Cluuifv the <ignah (analog; or in circuit<. the uf\Cvcr..11 !iq..,id·rnca.wrinJ,! £11•frii1111hycomcninga0Jfog fonn Ix: u;:.:ful.
1-3 cununon that .;on1ai11 dn:uitry. Oi1c1m thedemantlfoccomputerandelo::tronic> and opponunitics
1·5 A11a(1<:<"""<!\"cm!!ugic·levdindicator circ\lit>. fll/rrprerlngie probe readings durtns ofadii;ical circuit U11ders111mf1hcdefini!i(m;ofJ/fGlf. (.O!V.Jndu111fr:ji11r:dwhcnoh>.ervingk1gic level; in both TTl. CMOS digital circuitry.
1·5 fJemmr.11wrethcu.cof><.'Vcr.1lM>
tal in nawre. Historically. most electronic pnxlucls contained a.irnlog circuitry. Most newly designed electronic devices rn111ain digit:il circuitry. This chapter introduces you to the world of digital electronics. What:iretheduesr.h;itnnelectronicproduct n111rai11.1· di&iWl drr.uirry? Signs that n device contains digital circuitry indude: I. it have a disphiy that shows numbers, letters. pictures, or video?
2. Docs it have a memory or can it More information?
3. C;m the dc\•icc he programmed'!
4. C;in it he conncc!e<l l(1 the ln1cmc1?
If the answer to any one of the four questions is yes. then the product probably contains digital circuitry. Digital circuitry is quickly hecoming pe1vasive because of its ad1'antagc.1 over analog including:
I to Jesign using modern integrated (!Cs). Information stornge is to • , h!
Key terms are carefully defined and explained in the text and listed in the margins so students can easily identify them.
programs. With its easy-to-read style, numerous fullcolor illustrations, and accessible math level, the text is ideal for readers who need to learn the essentials of digital electronics and apply them to on-the-job situations.
Each chapter begins with a list of learning outcomes that tell the reader what he or she should expect to accomplish by the end of the chapter. The outcomes are tied to the chapter subsections.
S11/)/lfy1hrmi.ni11t-:u"mtfi11rach.1wtrmell/
!. Rc!erLo Fi!!.. 1·2. The +5-V li:vel of the :1ho be ca!k-U a logical ! or a <HIGH. LOW). A(n) (anl;llog, digi1al) di:vicc i.\Onc that
3. Refer to Fig. l-4 The input to the elecmmicblock (analog, digiiall signal. 4. Refert0Fig. l-4.Theo11tpmfromthe efcetronic hlock ctu.,silied a(n) (analog, digital) sign;iJ 5. An annlog circuit is one that analogsignalswhileadigitalcircuit proccsses OUTPUT n__
The he.111drd111u/1111m/1er .\\"Ht'/11 the !6 symboh 0, I. 2. 3, 4, 5. 6, 7. 8. 9. A. B. C. D. E. and F and is 1cfcrrcd to the fxni•16 .<y1IL'lll. Figure 2-9 the
and hexadecimal representations for the
numbers 0 thmugh 17. The !cuer "A" slamh for decimal
and
The adv;inlage ut the hc:irndccimal sy,,tcm is in converting directly from a 4-hit binary number. For instance. F for the -l·bit binary number l 11 ! He.w· detima/ 11111Uti1111 is typically ug."d to ;i binary number. For the hexadecimal number A6 y.uuld rcprc ..ent the 8·bit binary number !UJUOlIU. Hexudcc1mal notatmn is widely usi:d in micmprocc.uor-lm.1t:d f_Y\tt.'1111 to repre.\Cnt 4. 8-. !6-, 32·, or 6-1-·hit binary numbers The numhcr lOrt:prc).Cnh how manyob· It can he from the table in Fig. 2-9 that the number IOcouldmc:m ten ohjccts, two nhjt.-Cb. or objects depend· ing on the of the number. Subsuipfl arc :iddcd to a number to indicate the of the numh-::r. \Ub?>Cripts, !he number 10"' repre,1,cnts ten The subscript {IOinthisexample) indic;itcsit isalwfc JO.or decimal. number. thc number 10, two objects since this is in binary (bi11e2). Again suhscripls. the number
for
The self-tests can either help students identify areas that need further study or serve as positive reinforcement for material that students already know. After completing a self-test, students may check their answers in the Answers to Self-Tests sections at the end of each chapter.
Aphotographichls!oryof the computerOneotthefirstcomputerswas the Eniac (upperfelt), devel· oped inthe1940s.The1970smarkedtheexpandeduseofthecomputerbybusmesses.The mainframecomputer (uppernght) wasthe100101thetime.Jn the 1980spersona!computerssuchasthe Applel!e (lowerleft) broughtcomputersintnourhomesand sehools. Today, perS-Onal computers can goanywtiere,aslaptopcomputers(lowertighl}increaselnpopu!arity
__________ a comhinati{ln of both. The to::chniciims AChanging Acid. E!ei:tmn!cs Is among Ille most exciting lxritd ;1 prototype (1r troublc)horJI and rcp;iir :ireasoftechnicals!udy.Newdevelopmentsarereporteddigital.analog:,nndcombined weekly. lnterestiogly, m-OSt dtwelopments are based on the Anulogd.:1111111ic 11·1t<:m\ haw been popular
1·2 Why Use Digital Circuits? Ue,ignct'i and technicians must huvc a v.mldng knowledge of both analog and digital The mint <ledde if the will ul.( an:1!og or digital or in milit;iry applications such as tire con· tro!oo.\hip.>. Mo)t rcal·wnrld inforrnulion is mw/og in nature. NJtural phenomena, a.> time, temperature. lrnmidicy. wind r;idiation. ani.J sound inten,ity. :ire :ma lug in nature You proh;ib!y have ;ilrc;idymea$1ircd voltage,
Digital Circuitry: Advontoges and limitotions
Some of the :idvanwgc\ ror dii;'1tal cir· cuitry lnJ.!ead of anal0<,; arc nJ. !bllow': l can be u:-cd with few extcrn;ilcomponent.\. lnfounaci,1ncanbc\torcdfor,hort pt!rioclsorinJelinitdy
J. Darn can he for prt:cbe t:a!cubtion'
4. Systems can be more e:i..-ily u,Jng conipaiihk digital logic
5. Systems cm1 be programmed and Mime manrr.:r ol "intclllgencc" 6 Al?hnnumeric,picture,and video
7. Digi1al dri:uib are uffix:ied by unwanted de<.:uic:1tinteikn::ocet":l!b.J11(1i1e 8. Suchcircuitsarecompaub!ewith the The limi/(/f/flll\ ojdiir;1talcirnii11y are :I.\
! Mo.'l ewnl\arein nature.
2 An;i!og hU\u;1!!y 'impler and fa.-ier. Digital a1e ;ipp.::aring in rnurc and more primarily of reliable digital Other for their growing popularity arc ac1:uracy. added\tll· hilitv. comouler commuibilitv. mcmocv, ea;.c
Critical facts and principles are reviewed in the Summary and Review section at the end of each chapter.
in comerting a more cump!katcd m;J.:tterm c\prcs,ion to it' m11nem1 form. twm maxt1:rm-to·111intern1 or minterm-to-ma,. lt:rmforin,u'l!co111u1onlyumkrt;ikentogc1rid of Jong in the Buoleln rhe new e:umple iJlu,trated in Fi!!. 4-46 will change the e:tprc ,ion (A+ 8 +(;}· (;r:;:s-+c)= Yto mime1m equivalent :md dim111;uethelongoverbar.Carcful!yfollow1he comer:.ion procc. , in Fi!!- The of thhcun\Cr.>itJn)iclJ,th<: iuinccnu IU1mA B C + A B - C = Y. which p.:rfonm C:.'<lt:t!y the \3mc kl\!k fm1<:uo11 the m;J.:tlt:rrn !A+B +Cl(...l.+ B +0= Y. The rnm1ermcxpres.,ioncanhewrmen inconven· t\lmJJ form B · C +A·fl. C= Yu,\n!! O\'t:r!iJr:. or in !he 'h\lftcncd kcybourd ABC+A'B·c = Yu.,ing Jt hc that the logic db· grnm< that ""ould hc wird U'>ing the maxtern1
History of Electronics
GeorgeBoole was tiom 10Lir;;:oln, Eru]!and.onNovember 2, 1815. HewasaseU-taughtmatflemaucran wtc inventedmooem symbolicklgicandpioneered thecaJculvsofaperat0<s.arounct 1850,Ge<lrge&Joiecreated Booteana!gebra,whidlunderlies thetheoryoflogrc.
The features History of Electronics and About Electronics add depth to the topics and highlight new and interesting technologies or facts.
connections encourage students to do online research on certain topics.
Chapter l Summary and Review
bouttheuthor
Over several decades, Roger L. Tokheim has published many textbooks and lab manuals in the areas of digital electronics and microprocessors. His books have xiv About the Author
been translated into nine languages. He taught technical subjects including electronics for more than 35 years in public schools.
Safety
Electric and electronic circuits can be dangerous. Safe practices are necessary to prevent electrical shock, fires, explosions, mechanical damage, and injuries resulting from the improper use of tools.
Perhaps the greatest hazard is electrical shock. A current through the human body in excess of 10 milliamperes can paralyze the victim and make it impossible to let go of a "live" conductor or component. Ten milliamperes is a rather small amount of current flow: It is only ten one-thousandths of an ampere. An ordinary flashlight can provide more than 100 times that amount of current!
Flashlight cells and batteries are safe to handle because the resistance of human skin is normally high enough to keep the current flow very small. For example, touching an ordinary 1.5- V cell produces a current flow in the microampere range (a microampere is onemillionth of an ampere). The amount of current is too small to be noticed.
High voltage, one the other hand, can force enough current through the skin to produce a shock. If the current approaches 100 milliamperes or more, the shock can be fatal. Thus, the danger of shock increases with voltage. Those who work with high voltage must be properly trained and equipped.
When human skin is moist or cut, its resistance to the flow of electricity can drop drastically. When this happens, even moderate voltages may cause a serious shock. Experienced technicians know this, and they also know that so-called low-voltage equipment may have a highvoltage section or two. In other words, they do not practice two methods of working with circuits: one for high voltage and one for low voltage. They follow safe procedures at all times. They do not assume protective devices are working. They do not assume a circuit is off even though the switch is in the OFF position. They know the switch could be defective.
Even a low-voltage, high-current-capacity system like an automotive electrical system can be quite dangerous. Short-circuiting such a system with a ring or metal watchband can cause very severe burnsespecially when the ring or band welds to the points being shorted.
As your knowledge and experience grow, you will learn many specific safe procedures for dealing with electricity and electronics. In the meantime:
1. Always follow procedures.
2. Use service manuals as often as possible. They often contain specific safety information. Read, and comply with, all appropriate material safety data sheets.
3. Investigate before you act.
4. When in doubt, do not act. Ask your instructor or supervisor.
General Safety Rules for Electricity and Electronics
Safe practices will protect you and your fellow workers. Study the following rules. Discuss them with others, and ask your instructor about any you do not understand.
1. Do not work when you are tired or taking medicine that makes you drowsy.
2. Do not work in poor light.
3. Do not work in damp areas or with wet shoes or clothing.
4. Use approved tools, equipment, and protective devices.
5. Avoid wearing rings, bracelets, and similar metal items when working around exposed electric circuits.
6. Never assume that a circuit is off. Double-check it with an instrument that you are sure is operational.
7. Some situations require a "buddy system" to guarantee that power will not be turned on while a technician is still working on a circuit.
8. Never tamper with or try to override safety devices such as an interlock (a type of switch that automatically removes power when a door is opened or a panel removed).
9. Keep tools and test equipment clean and in good working condition. Replace insulated probes and leads at the first sign of deterioration.
10. Some devices, such as capacitors, can store a lethal charge. They may store this charge for long periods
of time. You must be certain these devices are discharged before working around them.
11. Do not remove grounds and do note use adaptors that defeat the equipment ground.
12. Use only an approved fire extinguisher for electrical and electronic equipment. Water can conduct electricity and may severely damage equipment. Carbon dioxide (C0 2 ) or halogenated-type extinguishers are usually preferred. Form-type extinguishers may also be desired in some cases. Commercial fire extinguishers are rated for the type of fires for which they are effective. Use only those rated for the proper working conditions.
13. Follow directions when using solvents and other chemicals. They may be toxic, flammable, or may damage certain materials such as plastics. Always read and follow the appropriate material safety data sheets.
14. A few materials used in electronic equipment are toxic. Examples include tantalum capacitors and beryllium oxide transistor cases. These devices should not be crushed or abraded, and you should wash your hands thoroughly after handling them. Other materials (such as heat shrink tubing) may produce
irritating fumes if overheated. Always read and follow the appropriate material safety data sheets.
15. Certain circuit components affect the safe performance of equipment and systems. Use only exact or approved replacement parts.
16. Use protective clothing and safety glasses when handling high-vacuum devices such as picture tubes and cathode-ray tubes.
17. Don't work on equipment before your know proper procedures and area aware of any potential safety hazards.
18. Many accidents have been caused by people rushing and cutting corners. Take the time required to protect yourself and others. Running, horseplay, and practical jokes are strictly forbidden in shops and laboratories.
19. Never look directly into light-emitting diodes or fiber-optic cables; some light sources, although invisible, can cause serious eye damage.
Circuits and equipment must be treated with respect. Learn how they work and the proper way of working on them. Always practice safety: your health and life depend on it.
Digital Electronics
learning Outcomes
This chapter will help you to:
1-1 Identify several characteristics of digital circuits as opposed to analog circuits. Differentiate between digital and analog signals, and identify the HIGH and LOW portions of a digital waveform.
1-2 Classify the signals (analog or digital) in several application circuits. Analyze the operation of several liquid-measuring circuits. Explain why converting analog inputs (currents and voltages) from sensors to digital form can be useful.
1-3 List several common pieces of electronic gear that contain digital circuitry. Discuss the demand for computer and electronics technicians, and identify training opportunities.
1-4 List three types of multivibrators, and describe how they generate types of digital signals. Analyze several multivibrator and switch debouncing circuits.
1-5 Analyze several logic-level indicator circuits. Interpret logic probe readings during testing of a digital circuit. Understand the definitions of HIGH, LOW, and undefined when observing logic levels in both TIL and CMOS digital circuitry.
1-6 Demonstrate the use of several lab instruments.
ngineers generally classify electronic circuits as being either analog or digital in nature. Historically, most electronic products contained analog circuitry. Most newly designed electronic devices contain digital circuitry. This chapter introduces you to the world of digital electronics.
What are the clues that an electronic product contains digital circuitry? Signs that a device contains digital circuitry include:
1. Does it have a display that shows numbers, letters, pictures, or video?
2. Does it have a memory or can it store information?
3. Can the device be programmed?
4. Can it be connected to the Internet?
If the answer to any one of the four questions is yes, then the product probably contains digital circuitry.
Digital circuitry is quickly becoming pervasive because of its advantages over analog including:
1. Generally, digital circuits are easier to design using modem integrated circuits (ICs).
2. Information storage is easier to implement with digital.
3. Devices can be made programmable with digital.
4. More accuracy and precision are possible.
5. Digital circuitry is less affected by unwanted electrical interference called noise.
All persons working in electronics must have knowledge of digital electronic circuits. You will use simple integrated circuits and displays to demonstrate the principles of digital electronics.
Identifying digital products
Advantages af digital
Analog signal
Volt-ohm-millimeter
HIGH and LOW signals
Digital multimeter
Digital circuits
1-1
V\Jhat IsaDigitalSignal?
In your experience with electricity and electronics you have probably used analog circuits. The circuit in Fig. 1- l(a) puts out an analog signal or voltage. As the wiper on the potentiometer is moved upward, the voltage from points A to B gradually increases. When the wiper is moved downward, the voltage gradually decreases from 5 to 0 volts (V). The waveform diagram in Fig. 1-l(b) is a graph of the analog output. On the left side the voltage from A to B is gradually increasing to 5 V; on the right side the voltacre b is gradually decreasing to 0 V. By stopping the potentiometer wiper at any midpoint, we can get an output voltage anywhere between O and 5 V. An analog device, then, is one that has a signal which varies continuously in step with the input.
A digital device operates with a digital signal. Figure 1-2(a) pictures a square-wave generator. The generator produces a square waveform that is displayed on the oscilloscope. The digital signal is only at +5 V or at 0 V, as diagrammed in Fig. l-2(b). The voltage at point A moves from 0 to 5 V. The voltage then stays at +5 V for a time. At point B the voltage drops immediately from +5 to 0 V. The voltage then stays at O V for a time. Only two voltages are present in a digital electronic circuit. In the waveform diagram in Fig. l-2(b) these voltages are labeled HIGH and LOW The HIGH voltage is +5 V; the LOW voltage is 0 V. Later we shall call the HIGH voltage (+5 V) a logical 1 and the LOW voltage (0 V) a logical 0. Circuits that handle only HIGH and LOW signals are called digital circuits.
The digital signal in Fig. 1-2(b) could also be generated by a simple on-off switch. A digital signal could also be generated by a transistor turning on and off Digital electronic signals are usually generated and processed by integrated circuits (ICs).
Both analog and digital signals are represented in graph form in Figs. 1-1 and 1-2. A signal can be defined as useful information transmitted within, to, or from electronic circuits. Signals are commonly represented as a voltage varying with time, as they are in Figs. 1-1 and 1-2. However, a signal could be an electric current that either varies continuously (analog) or has an on-off (HIGH-LOW)
Wiper moving up
(a) (b) ..
Wiper moving down
1-1 (a) Analog output from a potentiometer. (b) Analog signal waveform.
characteristic (digital). Within most digital circuits, it is customary to represent signals in the voltage versus time format. When digital circuits are interfaced with nondigital devices such as lamps and motors, then the signal can be thought of as current versus time.
The standard volt-ohm-millimeter (VOM) shown in Fig. l-3(a) is an example of an analog measuring device. As the voltage, resistance, or current being measured by the VOM increases, the needle gradually and continuously moves up the scale. A digital multimeter (DMM) is shown in Fig. 1-3(b). This is an example of a digital measuring device. As the Square-wave generator 1---_____,a (a) B
A Time (b)
·1-2 (a) Digital signal displayed on scope. (b) Digital signal waveform.
(a)(b) (a) Analog meter. (6) Digital multimeter (DMM). Courtesy Fluke Corporation. Reproduced with permission
current, resistance, or voltage being measured by the DMM increases, the display jumps upward in small steps. The DMM is an example of digital circuitry taking over tasks previously Supply the missing word in each statement.
1. Refer to Fig. 1-2. The + 5- V level of the ____ (analog, digital) signal could also be called a logical 1 or a ____ (HIGH, LOW).
2. A(n) (analog, digital) device is one that has a signal which varies continuously in step with the input.
INPUT
performed only by analog devices. This trend toward digital circuitry is growing. Currently, the modern technician's bench probably has both a VOM and a DMM.
3. Refer to Fig. 1-4. The input to the electronic block is classified as a(n) ____ (analog, digital) signal.
4. Refer to Fig. 1-4. The output from the electronic block is classified as a(n) ____ (analog, digital) signal.
5. An analog circuit is one that processes analog signals while a digital circuit processes signals.
OUTPUT
Trend toward digital circuitry
Fig. 1-4 Block diagram of electronic circuit shaping a sine wave into a square wave.
A Changing Field. Electronicsisamongthemostexciting l!1 areasoftechnicalstudy.Newdevelopmentsarereported weekly.Interestingly,mostdevelopmentsarebasedonthe fundamentalslearnedinthefirstclassesinelectricity,analog anddigitalcircuits,computertechnologyandrobotics,and communications.
1-2WhyUseDigitalCircuits'?
Electronics designers and technicians must have a working knowledge of both analog and digital systems. The designer must decide if the system will use analog or digital techniques or
a combination of both. The technicians must build a prototype or troubleshoot and repair digital, analog, and combined systems.
Analog electronic systems have been popular in the past. Older TVs, telephones, and automobiles featured analog circuits. Before modern digital computers, analog computers were used in some military applications such as fire control on ships.
Most real-world information is analog in nature. Natural phenomena, such as time, temperature, humidity, wind speed, radiation, and sound intensity, are analog in nature. You probably have already measured voltage,
current, resistance, power, capacitance, inductance, and frequency in other electricity and electronics courses. Other things to be measured include pressure, weight, oxygen (and other gases), ultrasonic sound, acceleration and tilt, vibration, direction (compass), global positioning, proximity, magnetic fields, linear distance, and angle of rotation (angular speed). They are all analog in nature. Engineers and technicians commonly use sensors to measure these things. Many sensors emit an analog signal.
A simple analog electronic system for measuring the amount of liquid in a tank is illustrated in Fig. 1-5. The input to the system is a varying resistance. The processing proceeds according to the Ohm's law formula, I = V/ R. The output indicator is an ammeter which is calibrated as a water tank gauge. In the analog system in Fig. 1-5 as the water rises, the input resistance drops. Decreasing the resistance R causes an increase in current (/). Increased current causes the ammeter (water tank gauge) to read higher.
The analog system in Fig. 1-5 is simple and efficient. The gauge in Fig. 1-5 gives an indication of the water level in the tank. If more information is required about the water level, then a digital system such as the one shown in Fig. 1-6 might be used.
Digital systems are required when data must be stored, used for calculations, or displayed as numbers and/or letters. A somewhat more complex arrangement for measuring the amount of liquid in a water tank is the digital system shown in Fig. 1-6. The input is still a variable resistance as it was in the analog system. The resistance is converted into numbers by the analog-to-digital (AID) converter. The central processing unit (CPU) of a computer can manipulate the input data, output the information, store the information, calculate things such as flow rates in and out, calculate the time until the tank is full (or empty) based on flow rates, and so forth. Digital systems are valuable when calculations, data manipulations, data storage, and alphanumeric or video outputs are required. Data transfers via the Internet are common.
Analog-ta-digital (A/D) converter
Central processing unit (CPU)
.!::'._(constant)
Watertank
Fig. 1-S Analog system used to interpret float level in water tank
Fig. Hi Digital system used to interpret float level in water tank
Application: Automobile Fuel Indicators
Older automobile circuitry was analog in nature. Consider the traditional fuel gauge system sketched in Fig. l-7(a). The fuel tank sending unit has a float that moves a wiper on a resistive material. Increasing the fuel level in the tank raises the float, causing the wiper to move left on the resistor. The resistor's value decreases. Decreased circuit resistance causes an increase in current in the series circuit (via Ohm's law, I= V/ R). The increased current causes the needle on the fuel gauge (an ammeter) to move clockwise toward F on the meter face. The older-style fuel gauge diagram in Fig. l-7(a) is an example of an analog circuit.
Newer automobiles may use the information from the fuel tank sending unit for several purposes. Figure l-7(b) shows the analog voltage from the fuel tank sending unit entering the instrument panel module. The computer module converts the analog input to digital information (AID converter). The computer module also receives signals from the vehicle speed sensor, engine control module (ECM). The input information is processed by the computer module. The instrument control module will drive a traditional-looking fuel gauge located on the instrument panel. A tachometer is probably also located on the instrument panel. With the inputs
shown in Fig. l-7(b), the instrumentation computer module calculates the average-fuel-consumption and miles-to-empty data. The driver sees this information displayed on an LCD screen.
It will be noted that information from the sensors in Fig. l-7(b) comes in various forms. The fuel tank sending unit delivers a variablevoltage signal to the computer module. With higher levels of fuel in the tank the sending unit generates a higher positive voltage.
The vehicle speed sensor sends a variablefrequency signal. At lower vehicle speeds the sensor emits a low-frequency signal. At higher speeds a high-frequency signal is sent to the computer module.
The engine control module sends several digital signals to the instrument control module. The engine control module determines how much fuel is injected into the cylinders of the engine and the timing.
resistor Fueltank sendingunit 1------1
,,Fuelgauge ;(- !) Float(ammeter)
Automobilefueltank (a)
1-7 [al. fuel tank sending unit and fuel gauge. (b) Modern automobile fuel 1nd1cator system with computer module.
Digital Circuitry: Advantages and limitations
Some of the advantages for using digital circuitry instead of analog are as follows:
1. Inexpensive ICs can be used with few external components.
2. Information can be stored for short periods or indefinitely.
3. Data can be used for precise calculations.
4. Systems can be designed more easily using compatible digital logic families.
5. Systems can be programmed and show some manner of "intelligence."
6. Alphanumeric, picture, and video information can be viewed using a variety of electronic displays.
Answer the following questions.
6. Generally, electronic circuits are classified as either analog or----
7. Measurements of time, speed, weight, pressure, light intensity, and position are ____ (analog, digital) in nature.
8. Refer to Fig. 1-5. As the water level drops, the input resistance increases. This causes the current I to (decrease, increase) and the water level gauge (ammeter) will read---(higher, lower).
9. Refer to Figs. 1-5 and 1-6. If this water tank were part of the city water system, where rates of water use are important, the system in Fig. (1-5, 1-6) would be most appropriate.
7. Digital circuits are less affected by unwanted electrical interference called noise.
8. Such circuits are compatible with the Internet and computers.
The limitations of digital circuitry are as follows:
1. Most real-world events are analog in nature.
2. Analog processing is usually simpler and faster.
Digital circuits are appearing in more and more products primarily because of low-cost, reliable digital ICs. Other reasons for their growing popularity are accuracy, added stability, computer compatibility, memory, ease of use, simplicity of design, and compatibility with a variety of displays.
10. True or false. The most important reason why digital circuitry is becoming more popular is that digital circuits are usually simpler and faster than analog circuits.
11. Refer to Fig. 1-7(a). This traditional auto fuel tank gauge assembly that senses and indicates the fuel level is an example of a(n) (analog, digital) circuit.
12. Refer to Fig. l-7(b). The input voltage from the fuel tank sending unit is a digital signal before it enters the instrument panel module. (T or F)
13. Refer to Fig. l-7(b). The input from the enaine control module (ECM) having to I:> do with fuel flow and time is ____ (analog, digital) in nature.
1-3 Where Are Digital Circuits Used'?
Digital electronics is a huge and rapidly expanding field. The global system of interconnected computer networks called the Internet serves billions of users. Digital computers, in
all their forms, serve as the backbone of the Internet. The Internet consists of academic, business, private, and government networks. The Internet allows users to access huge amounts of information using the World Wide Web (WWW). The Internet also supports twoway communications with e-mail and social
Internet Connection
Search the web for the following terms: fuel tank sending unit, vehicle speed sensor. and engine control module.
networking sites including Facebook. Huge amounts of data are transferred via the Internet by banks, manufacturers, the military, medical professions, security companies, governments, and businesses. The global economy could hardly survive without the capabilities of digital computers, huge memory banks, and the Internet.
Millions of individual electronic devices must be designed, manufactured, tested, and repaired by technicians. Electronics technicians and engineers are in great demand. A few applications of digital electronics are suggested by the images on the tablet sketched in Fig. 1-8.
Jobs for technicians are available with most high-technology businesses. Many government jobs call for some skills in computer technology including electronics. Highly skilled technicians work on extremely sophisticated military electronics. It is reported that the half the cost of some military aircraft is electronics in nature. The military has many outstanding advanced electronics training programs. Ask about these when you visit a military recruiter.
The driving experience of a modern automobile has been greatly enhanced by electronics. Automobile engines have more power, run smoother, and use less fuel due to precise electronic engine control. More automobiles contain entertainment systems that are outstanding. Bluetooth for cell phones, GPS, and touch screen displays are common. Assisted parking and blind spot detection are standard on many autos. Safety features like antiskid and traction and stability control systems depend digital electronics. Ask your school counselor about opportunities in your area.
To cut down on thefts, the key to your automobile may contain a transmitter whose signal is picked up by a transponder ECM. The transponder reads the wireless signal from the key, allowing the engine to start. Some modern automobiles have more than 50 electronic control modules (computers). Auto mechanics must be trained in modern electricity and electronics. Check with your area technical college to survey training openings. Auto manufacturers also run outstanding training classes.
Most measuring instruments you may use at work in the lab will contain digital circuitry. These might include a logic probe, digital multimeter (DMM), capacitance meter, frequency counter, function generator (signal generator), and programmable power supply. Modern oscilloscopes may also feature some digital circuitry.
Many hands-on lab activities will be provided. A updated Experiments Manual for Digital Electronics is available that presents many hands-on lab activities chapter by chapter.
Answer the following questions.
14. List at least four devices that use digital circuitry.
15. Computer and electronics technicians are in great demand. (T or F)
16. The military has excellent electronics training schools. (T or F)
How Do You Generate a DigitalSignal'?
Digital signals are composed of two welldefined voltage levels. Most of the voltage levels used in this class will be about + 3 V to +5 V for HIGH and near 0 V (GND) for LOW. These are commonly called TTL voltage levels because they are used with the transistortransistor logic family of ICs.
Generating a Digital Signal
A TTL digital signal could be made manually by using a mechanical switch. Consider the simple circuit shown in Fig. l-9(a). As the blade of the single-pole, double-throw (SPOT) switch is moved up and down, it produces the digital waveform shown at the right. At time period t 1 the voltage is 0 V, or LOW. At t 2 the voltage is +5 V, or HIGH. At t 3 the voltage is again 0 V, or LOW, and at t4 , it is again +5 V, or HIGH. The action of the switch causing the LOW, HIGH, LOW, HIGH waveform in Fig. 1-9(a) is called toggling. By definition, to toggle (the verb) means to switch over to an opposite state. As an example in Fig. 1-9(a), if the switch moves from LOW to HIGH we say the output has toggled. Again if the switch moves from HIGH to LOW we say the output has again toggled. One problem with a mechanical switch is contact bounce. If we could look very carefully at a switch toggling from LOW to HIGH, it might look like the waveform in Fig. 1-9(b). The waveform first goes directly from LOW to
17. All auto mechanics that are specialists in electronics are self-taught. (T or F) 18. List at least two measuring instruments you will use as a technician and that contain digital circuitry.
HIGH (see point A) but then, because of contact bounce, drops to LOW (see point B) and then back to HIGH again. Although this happens in a very short time, digital circuits are fast enough to see this as a LOW, HIGH, LOW, HIGH waveform. Note that Fig. 1-9(b) shows that there is actually a range of voltages that are defined HIGH and LOW. The undefined region between HIGH and LOW may cause trouble in digital circuits and should be avoided.
To cure the problem illustrated in Fig. l-9(b), mechanical switches are sometimes debounced. A block diagram of a debounced logic switch is shown in Fig. 1-9(c). Note the use of the debouncing circuit, or latch. Some of the mechanical logic switches you will use on laboratory equipment will have been debounced with latch circuits. Latches are sometimes called flip-flops. Notice in Fig. 1-9(c) that the output of the latch during time period t 1 is LOW but not quite 0 V. During t 2 the output of the latch is HIGH even though it is something less than a full +5 V. Likewise t 3 is LOW and t4 is HIGH in Fig. 1-9(c).
It might be suggested that a push-button switch be used to make a digital signal. If the button is pressed, a HIGH should be generated. If the push button is released, a LOW should be generated. Consider the simple circuit in Fig. 1- IO(a). When the push button is pressed, a HIGH of about +5 V is generated at the output. When the push button is released, however, the voltage at the output is undefined. There is an open circuit between the power supply and the output. This would not work properly as a logic switch.
TTL voltage levels
Transistor· transistor lagic
Debaunced lagic switch
Digital waveform Latch (flip-flap)
Contact bounce
One-shat multivibratar
Multivibratar types: astable, bistable, and monostable
Free-running MV (clack)
1HIGH -_L (a) A HIGH Undefinedregion LOW (b)
(c)
Fig. 1-9 (a) Generating a digital signal with a switch. (b) Waveform of contact bounce caused by a mechanical switch. (c) Adding a debouncing latch to a simple switch to condition the digital signal. ___l__ Pressed=HIGH n------+-OUTPUT Released=? One-shot multivibrator
5V-=-
5V-=-
Fig. 1-10 (a) Push button will not generate a digital signal. (b) Push button used to trigger a one-shot multivibrator for a singlepulse digital signal.
A normally open push-button switch can be used with a special circuit to generate a digital pulse. Figure 1-lO(b) shows the push button connected to a one-shot multivibrator circuit. Now for each press of the push button, a single short, positive pulse is output from the one-shot circuit. The pulse width of the output is determined by the design of the multivibrator and not by how long you hold down the push button.
Multivibrator ·Circuits
Both the latch circuit and the one-shot circuit were used earlier. Both are classified as multivibrator (MV) circuits. The latch is also called a flip-flop or a bistable multivibrator. The oneshot is also called the monostable multivibrator. A third type of MV circuit is the astable multivibrator. This is also called a free-running
multivibrator. In many digital circuits it may be referred to simply as the clock.
The free-running MV oscillates by itself without the need for external switching or an external signal. A block diagram of a free-running MV is shown in Fig. 1-11. The free-running MV generates a continuous series of TTL level pulses. The output in Fig. 1-11 alternately toggles from LOW to HIGH, HIGH to LOW, etc.
In the laboratory, you will need to generate digital signals. The equipment you will use will have slide switches, push buttons, and freerunning clocks that will generate TTL level signals similar to those shown in Figs. 1-9, 1-10, and 1-11. In the laboratory, you will use logic switches which will have been debounced using a latch circuit as in Fig. l-9(c). You will also use a singlepulse clock triggered by a push-button switch.
Free-running multivibrator
Fig. 1-11 Free-running multivibrator generates a string of digital pulses.
The single-pulse clock push button will be connected to a one-shot multivibrator as shown in Fig. 1-lO(b). Finally, your equipment will have a free-running clock. It will generate a continuous series of pulses, as shown in Fig. 1-11.
Wiring a Multivibrator
Astable, monostable, and bistable MVs can all be wired using discrete components (individual resistors, capacitors, and transistors) or purchased in IC form. Because of their superior performance, ease of use, and low cost, the IC forms of these circuits will be used in this course. A schematic diagram for a practical free-running clock circuit is shown in Fig. l-12(a). This clock circuit produces a low-frequency (1- to 2-Hz) TTL level output. The heart of the free-running clock circuit is a common 555 timer IC. Note that several resistors, a capacitor, and a power supply must also be used in the circuit.
A typical breadboard wiring of this freerunning clock is sketched in Fig. l-12(b). Notice the use of a solderless breadboard. Also note that pin 1 on the IC is immediately counterclockwise from the notch or dot near the end of the eightpin IC. The wiring diagram in Fig. l-12(b) is shown for your convenience. You will normally
have to wire circuits on solderless breadboards directly from the schematic diagram.
Wiring a Debounced Switch
Simple mechanical switches introduce problems when used as input devices to digital circuits. The push-button switch (SW) shown in Fig. 1-13(a) is being pressed or closed at point A (see output waveform). Because of switch bounce the output signal goes HIGH, LOW, and then HIGH again. Likewise when the push-button switch is released (opened) at point B, more bouncing occurs. Switch bounce from input switches must be eliminated.
To solve the problem of switch bounce, a debouncing circuit has been added in Fig. l-13(b). Now when the push-button switch is closed at point C (see output waveform), no bouncing occurs and the output toggles from LOW to HIGH. Likewise when SW 1 is opened at point D, no bouncing is observed on the waveform and the output toggles from HIGH to LOW.
An input switch with a debouncing circuit attached is drawn in Fig. 1-14. Observe that the 555 timer IC is at the heart of the debouncing circuit. When push-button switch SW1 is closed (see point E on waveform), the output toggles from LOW to HIGH. Later when SW1 is opened
OUTPUT
(a)
Fig. 1-12(a) Schematic diagram of a Free-running clock using a 555 timer IC.
Fig. 1-12[b) Wiring the free-running clock circuit on a solderless breadboard. Open B SW I 1
Debouncing circuit
Cl:se \ SW 1 \"-- Problem-switch bounce (a)
Close SW 1 (b)
Fig. ·1-13 (a) Switch bounce caused by a mechanical switch. (b) Debouncing circuit eliminates switch bounce.
(see point Fon wave-form), the output of the 555 timer IC remains HIGH for a delay period. After the delay period (about 1 second for this circuit) the output toggles from HIGH to LOW. The delay period can be adjusted by changing the capacitance value of capacitor C2 • Decreasing the capacitance
value of C2 will decrease the delay time at the output, while increasing c2 will increase the delay.
Wiring a One-Shot Multivibrator
A one-shot multivibrator (MV) is also called a monostable multivibrator. The one-shot circuit
Switch debouncing circuit.
responds to an input trigger pulse with an output pulse of a given width or time duration. A one-shot MV circuit that can be wired in the lab is drawn in Fig. 1-15. The 74121 oneshot multivibrator IC uses a simple push-button switch to raise the voltage at input B from GND to about + 3 V. This is the trigger voltage. When triggered, the one-shot MV outputs a short pulse at the two outputs. The normal output Q (pin 6) emits a short positive pulse about 2 to 3 ms
Timedelayrelated tovalueofC2 in duration. The complementary output Q emits the opposite output, or a short negative pulse. On digital devices called flip-flops the outputs are commonly labeled Q and Q (say not Q), and their outputs are always opposite or complementary. On complementary outputs, if Q is HIGH then Q is LOW but if Q is LOW then Q is HIGH. The outputs of the 74121 one-shot multivibrator IC come directly from an internal flip-flop and are therefore labeled Q and Q.
Pulsewidth (=2-3 msec)
One-shotMV (74121) Q
RExT/CExT 11 B Input CEXT
4 3 ns One-shot multivibrator circuit using the 74121 TTL IC.
0.1 µ,F
NOTE:Pulsewidthcanbeincreased C1
byincreasingvalueofeitherC1or R 3
Tciggec point (SW1closes)
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Ostiaks and Samoyedes, settle disputes, and deal out justice generally; the Russian merchants are on the outlook for buyers and sellers, the dishonest ones among them, and the swindling Syryani, for thoughtless drunkards, and the clergy for heathen to be converted. Among the Ostiaks and Samoyedes all sorts of agreements are made, weddings arranged, enemies reconciled, friends gained, compacts with the Russians formed, debts paid and new ones contracted. From all sides appear long trains of sledges drawn by reindeer, and one tshum after another grows up beside the market-place, each tshum surrounded by heavily-laden sledges containing the saleable acquisitions of the year. Every morning the owner, with his favourite wife in gala attire, proceeds to the booths to sell his skins and buy other commodities. They bargain, haggle, and attempt to cheat, and Mercury, as powerful as of yore, shows his might not only as the god of merchants but of thieves. Alcohol, though its retail sale is forbidden by the government, is to be had not only at every merchant’s, but in almost every house in Obdorsk, and it blunts the senses and dulls the intelligence of Ostiak and Samoyede, and impoverishes them even more than the muchdreaded reindeer plague. Brandy rouses all the passions in the ordinarily calm, good-tempered, inoffensive Ostiak, and transforms the peaceable, friendly, honest fellows into raging, senseless animals. Man and wife alike long for brandy; the father pours it down his boy’s throat, the mother forces it on her daughter, should they begin by rebelling against the destructive poison. For brandy the Ostiak squanders his laboriously-gained treasures, his whole possessions; for it he binds himself as a slave, or at least as a servant; for it he sells his soul, and denies the faith of his fathers. Brandy is an indispensable accompaniment to the conclusion of every business, even to conversion to the orthodox church. With the help of brandy a dishonest merchant can get possession of all an Ostiak’s skins, and without these, with empty purse and confused head, the man who arrived in Obdorsk full of hope and pride, returns to his tshum cheated, not to say plundered. He repents his folly and weakness, makes the best of resolutions, becomes tranquil in doing so, and soon remembers nothing except that he enjoyed himself excellently with his fellow tribesmen. First they had drunk together;
then men and women had kissed each other, then the men had beaten their wives, had tried their strength on each other, had even drawn their sharp knives, and, with flashing eyes, had threatened each other with death; but no blood had been shed; there had been a reconciliation; the women who had fallen on the ground, stupefied with blows and brandy, were lifted up tenderly, and were tended by other women; to celebrate the reconciliation an important compact had been made, a bridegroom was sought for the daughter, a little bride for the son; even a widow had been married, and they drank again to the occasion; in short, they had had a splendid time. That the government officials had shut up all those who were dead drunk, that all, all their money had gone the way of things perishable, had certainly been disagreeable, very disagreeable. However, the prison had opened again; after a time, the loss of the money had been got over, and only the golden recollection, over which they could gloat for a whole year, and the betrothal, so satisfactory to all parties, remained as permanent gain from the delightful festival.
The bridegroom and bride had also been at the fair, had drunk with the rest, and thus made each other’s acquaintance, and the bridegroom had agreed with his parents to choose the maiden as his wife, or rather had agreed to receive her. For it is the parents’ decision, not the consent of the couple themselves, that concludes a marriage among the Ostiaks. They may perhaps have some regard for the bridegroom’s wishes, may allow him to cast his affections on one or other of the daughters of his people, but they only send an agent to treat with the girl’s father if their own circumstances correspond with his. The maiden herself is not consulted, perhaps because, at the time of her betrothal, she is much too young to be able to decide upon her own future with discretion. Even the future husband has not reached his fifteenth year when the agent begins to treat for the twelve-year-old bride. In this case the general exhilaration of fair-time had considerably hastened the course of proceedings. The matrimonial agent had gained an immediate consent; the negotiations, often very protracted, had been at once begun, and thanks to brandy, which usually proves an evil demon, but in this case expedited matters, they were brought to a speedy conclusion. It had been agreed that Sandor, the young bridegroom,
should pay for his little bride, Malla, sixty reindeer, twenty skins of the white and ten of the red fox, a piece of coloured cloth, and various trifles such as rings, buttons, glass beads, head-dresses, and the like. That was little, much less than the district governor, Mamru, who was scarcely better off, had to give for his wife; for his payment consisted of a hundred and fifty reindeer, sixty skins of the Arctic and twenty of the red fox, a large piece of stuff for clothes, several head-dresses, and the customary trifles. But times were better then, and Mamru might well pay what was equivalent to more than a thousand silver roubles for his wife, who was stately, rich, and of good family.
The amount agreed on is paid; the nuptials of the young couple are celebrated. The relatives of the bride’s family come to her father’s tent to bring presents and to receive others from the bridegroom’s gift, which is laid out for everyone to see. The bride is arrayed in festive garments, and she and her friends prepare for the drive to the tshum of the bridegroom or of his father. Beforehand they have eaten abundantly of the flesh of a reindeer, fresh killed, according to custom. Only a few fish caught under the ice have been cooked today; the flesh of the reindeer was eaten raw, and when one began to grow cold a second was slaughtered. The bride weeps, as becomes departing brides, and refuses to leave the tshum in which she was brought up, but she is consoled and coaxed by all, and at last she is ready. A prayer before the domestic idol solicits the blessing of the heavenly Ohrt, whose sign, the divine fire Sornidud—in our eyes only the flaming northern light—had shone blood-red in the sky the evening before. The daughter is accompanied by her mother, who keeps close by her side, and even remains near her during the night. Mother and daughter mount one sledge, the rest of the invited kinsfolk mount theirs, and, in festive pomp, to the sound of the bells which all the reindeer wear on their harness, the wedding procession sets forth.
In his father’s tent the bridegroom awaits the bride, who modestly veils her face with her head-dress in the presence of her future father and brothers-in-law. This she continues to do after the marriage is consummated. A new banquet begins, and the guests,
who have been joined by the bridegroom’s relatives, do not disperse till late at night. But the next day the mother brings the young wife back to her father’s tent. A day later all the bridegroom’s relatives appear to demand her back again for him. Once more the low hut is filled with festive sounds; then the bride leaves it for ever, and is again conducted with pomp to the tshum which she is thenceforward to share with her husband, or with him and his father and brothers and sisters, or later on with another wife.
The sons of poor people pay at most ten reindeer for their brides; those of the fisher-folk only the most necessary furnishings of the tshum, and even these are often shared among several families; but their weddings, too, are made the occasion of a joyful festival, and there is as much banqueting as circumstances will allow.
The poorer Ostiaks marry only one wife, but the rich look upon it as one of the rights of their position to have two or more. But the first wife always retains her privileges, and the others appear to be rather her servants than her equals. It is otherwise, however, if she should have no children; for childlessness is a disgrace to the man, and a childless wife in the tshum, as elsewhere, is much to be pitied.
The parents are proud of their children, and treat them with great tenderness. It is with unmistakable happiness in look and gesture that the young mother lays her first-born in her bosom, or on the soft moss in the neat birch-bark cradle with its lining of mouldered willowwood and shavings; carefully she fastens the cover to both sides of the cradle, and envelops the head-end of the little bed with the mosquito curtain; but her ideal of cleanliness leaves much to be desired. As long as the baby is small and helpless she washes and cleanses it when she thinks it absolutely necessary. But when it grows bigger she only washes its face and hands once a day, using a handful of fine willow fibres as sponge, and a dry handful as towel, and afterwards looks on quite complacently when the little creature, who finds many opportunities for soiling itself, goes about in a state of dirt, to us almost inconceivable. This state of things comes gradually to an end when the young Ostiak is able to take care of himself; but even then, hardly anyone considers it necessary to wash after every meal, even should it have left stains of blood. The
children are as much attached, and as faithful to their parents as these are to them, and their obedience and submission is worthy of mention. To reverence parents is the first and chief commandment among the Ostiaks, to reverence their god is only the second. When we advised Mamru, the district governor already mentioned, to have his children taught the Russian language and writing, he replied that he saw the advantage of such knowledge, but feared that his children might forget the respect due to their father and mother, and thus break the most important commandment of their religion. This may be the reason why no Ostiak, who clings to the faith of his fathers, learns to do more than make his mark, a sort of scrawl binding on him and others, drawn upon paper, or cut in wood or reindeer-skin. Yet the Ostiak is capable and dexterous, able to learn whatever he is taught so quickly and easily that, at the early age at which he marries, he understands everything connected with the establishment and maintenance of his household. It is only in religious matters that he seems unwilling to trust to his own judgment, and on this account he, in most cases, shows unmerited respect for the shamans,[85] who profess to know more about religion than he does.
For our part, we regard the shaman, who claims the status of a priest among the Ostiaks as among the other Mongolian peoples of Siberia, as nothing short of an impostor. The sole member of the precious brotherhood with whom we came in contact, a baptized Samoyede, bore the sign of Christianity on his breast; according to report he had even been a deacon in the orthodox church, and yet he did duty as a shaman among the heathen Ostiaks. I learned later, on good authority, that he was no exception to the general rule; for all the shamans met with by my informant, Herr von Middendorf, during years of travel in Siberia, were Christians. I have already mentioned in the report of my travels that the shaman whom we met took us also for believers; but I have reserved my account of his performances and prophecies for to-day, as this description seems to me a fitting frame for such a picture.
To begin with, he demanded brandy as a fee, but was satisfied with the promise of a gift, and retired into a tent, saying that he would let
us know when his preparations were finished. Among these preparations, apparently, was the muffled beating of a drum which we heard after a considerable time; of other arrangements we discovered nothing. On a given signal we entered the tshum.
The whole space within the birch-bark hut was filled with people, who sat round in a circle pressing closely against the walls. Among the Ostiaks and Samoyedes, who were there with wives and children, there were also Russians with their families. On a raised seat to the left of the entrance sat the shaman Vidli; at his right, crouching on the floor, was an Ostiak, the master’s disciple at the time. Vidli wore a brown upper garment, and over it a kind of robe, originally white, but soiled and shabbily trimmed with gold braid; in his left hand he held a little tambour-like drum, in such a way that it shaded his face; in his right hand was a drum-stick; his head was uncovered, his tonsured hair freshly oiled. In the middle of the tshum a fire was burning, and now and again it blazed up and shed bright light on the motley throng, in the midst of which we sat down in the places reserved for us. A thrice-repeated, long-drawn cry, like a song from many voices, preluded by beating of the drum, greeted our entrance, and marked the beginning of the proceedings.
“That you may see that I am a man of truth,” said the master’s voice, “I shall now adjure the messenger of the heavenly will, who is at my behest, to appear among us and communicate to me what the gods have determined concerning your future. Later, you yourselves will be able to determine whether I have told you the truth or not.”
After this introduction, which was translated to us by two interpreters, the favourite of the gods struck the calf-skin, or rather reindeer-skin of his drum, with quick strokes which followed one another at equal intervals, but were indefinitely grouped, and accompanied his drumming with a song which, in the usual Samoyede fashion, was half-spoken, or rather muttered, and half-sung, and was faithfully repeated by the youth, whom we may call the clerk. The master held the drum so as to keep his face in shadow, and he also shut his eyes that nothing might distract his inward vision; the clerk, on the other hand, smoked even while he sang, and spat from time to time, just
as he had been doing before. Three slow, decided strokes brought the drumming and the song to an end.
“I have now,” said the master with dignity, “adjured Yamaul, the heavenly messenger, to appear among us, but I cannot say how much time must pass before he arrives, for he may be far off.”
And again he beat his drum and sang his incantation, concluding both song and accompaniment as before.
“I see two emperors before me; they will send you a writing,” spoke the messenger of the gods through his lips.
So Yamaul had been kind enough to appear in the tshum to oblige his favourite. Then the individual sentences of the heavenly message, with the invariable prelude of drumming and song, were uttered as follows:—
“Once again, next summer, you will traverse the same route as this year.”
“Then you will visit the summit of the Ural, where the rivers Ussa, Bodarata, and Shtchutshya begin their course.”
“On this journey something will befall you, whether good or evil I cannot tell.”
“Nothing is to be achieved at the Bodarata, for wood and pasture are lacking; here something might be accomplished.”
“You will have to render an account to your superiors; they will examine you and will be satisfied.”
“You will also have to answer to the three elders of your tribe; they also will examine your writings, and then come to a decision about the new journey.”
“The course of your journey will henceforward be happy and without accident; and you will find your loved ones at home in the best of health.”
“If the statements of the Russians who are still at Bodarata corroborate yours, two emperors will reward you.”
“I see no other face.”
The performance was at an end. On the Ural Mountains lay the last glow of midnight. Everyone left the tent, the faces of the Russians showing the same credulity as those of the Ostiaks and Samoyedes. But we invited the shaman to accompany us to our boat, loosened his tongue and that of his disciple with brandy, and plied him with all manner of cross-questions, some of them of the subtlest kind. He answered them all, without exception, without ever getting into a difficulty, without hesitation, without even reflection; he answered them full of conviction, and convincingly, clearly, definitely, tersely, and to the point, so that we recognized more clearly than before the extreme craftiness of the man with whom we had to deal.
He described to us how, even in his boyhood, the spirit had come upon him and had tortured him till he became the disciple of a shaman; how he had become more and more intimate with Yamaul, the messenger of the gods, who appears to him as a friendly man, riding on a swift horse, and carrying a staff in his hand; how Yamaul hastened to his help, and even, if need were, called down aid from heaven when he, the shaman, was struggling with evil spirits often for several days at a time; how the messenger of the gods must always communicate the message to him just as he received it, for that otherwise he felt every drum-beat as a painful stroke; how Yamaul, even to-day, though visible to him only, sat behind him in the tshum and whispered the words in his ear. He also informed us that, by his own art, or by the grace bestowed upon him, which even his conversion to Christianity could not weaken, he could reveal what was hidden, find what was stolen, recognize diseases, prophesy the death or recovery of the sick, see and banish the ghosts of the dead, work much evil, and prevent much evil, but that he did nothing but good, because he feared the gods; he gave us a clear and detailed, if not quite correct picture of the religion of the Ostiaks and Samoyedes; he assured us that all his people, as well as the Ostiaks, came to him in their troubles to ask advice, or to have the future unveiled, and that they did not doubt, but trusted in him and believed him.
The last statement is not correct. The great mass of the people may regard the shaman as a wise man, perhaps even as an intermediary between men and the gods, and possibly as the possessor of mysterious power; but many believe his words and works as little as other races do those of their priests. The real faith of the people is simpler and more child-like than the shaman approves of. It is here as elsewhere; the priest, or whoever acts as such, peoples heaven with gods, and councillors and servants of the gods, but the people know nothing of this celestial court.
According to the belief of the people there is enthroned in heaven Ohrt, whose name signifies “the end of the world”. He is an allpowerful spirit, who rules over everything but Death, and he is benevolently inclined towards men. He is the giver of all good, the bestower of reindeer, fish, and furred animals, the preventer of evil, and the avenger of lies, severe only when promises made to him are not fulfilled. Feasts are held in his honour, sacrifices and prayers are offered to him; the suppliant who prostrates himself before a sacred symbol thinks of him. The symbol, called a longch, may be of carved wood, a bundle of cloth, a stone, a skin, or anything else: it possesses no powers, affords no protection, it is in no sense a fetish! People assemble before a longch, place it in front of the tshum, lay dishes of fish, reindeer flesh, or other offering before it, place valuables before it, or even pack them inside it; but they always look up to heaven, and both their offerings and their prayers are intended for their god. Evil spirits dwell in heaven as on earth; but Ohrt is more powerful than they all; only Death is mightier than he. There is no everlasting life after death, and no resurrection; but the dead still wander as ghosts over the face of the earth, and have still power to do good or evil.
Fig. 65. The Burial of an Ostiak. When an Ostiak dies his spirit-life begins at once; so his friends proceed immediately to arrange for his burial. They had all assembled before his death, and as soon as life is extinct they kindle
a fire in the tshum in which the body lies, and keep it burning until they set out for the burial-place. A shaman is called to ask the dead where he wishes to lie. This is done by naming a place, and attempting to raise the head of the corpse. If the dead man approves he lets his head be raised; if he does not, three men cannot move it. Then the question must be repeated until the man gives his consent. Skilled persons are despatched to the chosen spot to prepare the grave, for this work often requires several days.
The burial-places are always in the tundra, on elevated spots, usually on a long ridge; the coffins are more or less artistically wrought chests, which are placed above the ground. Failing solid planks to construct the coffin, a boat is cut up and the corpse is laid in that; only the very poor people dig in the ground a shallow hollow in which to bury their dead.
The corpse is not washed, but is arrayed in festive garments, the hair anointed, and the face covered with a cloth. All the rest of the deceased’s clothing is given to the poor. The Ostiaks never touch the dead body of a stranger with their hands, but they do not hesitate to touch a loved relative, and even to kiss his cold face with tears in their eyes. The corpse is brought to the burial-place on a sledge, or in a boat, and is accompanied by all the relatives and friends. A reindeer-skin, on which the dead is to rest, is laid in the chest or coffin. At the head and sides are placed tobacco, pipes, and all manner of implements which the dead man was wont to use in his lifetime. Then the corpse is lifted with cords, carried to the chest, and laid on the bed thus prepared; the face is covered for the last time, a piece of birch-bark is spread over the open top of the chest, which, if the family be a rich one, is perhaps first covered with costly skins and cloths, the lid of the chest is put on above the sheet of bark, or at least heavy branches are laid close together upon it. Around and under the chest are laid such implements as could not be placed within it, but they are first broken up and thus rendered useless for the living, or, according to Ostiak ideas, made the ghosts of what they were.
Meanwhile, a fire has been kindled in the neighbourhood of the grave, and one or more reindeer slaughtered, and now the flesh is
eaten, raw or cooked, by the funeral company After the meal, the skulls of the slaughtered reindeer are fixed upon a pole, their harness is hung on the pole or on a tree, the bells they have worn on this, as on all solemn occasions, are hung on the top of the coffin itself, the sledge is broken to pieces and thrown beside the grave as its last ornament. Then the company travels homewards. Mourning is now silenced, and the daily round of life begins again.
But in the shades of night the ghost of the dead, equipped with his ghostly tools, begins his mysterious spirit-life. What he did while he walked among the living, he continues to do. Invisible to all he leads his reindeer to pasture, guides his boat through the waves, buckles on his snow-shoes, draws his bow, spreads his net, shoots the ghosts of former game, catches the ghosts of former fishes. During night he visits the tshum of his wife and children, causing them joy or sorrow. His reward is to be able to show beneficence to his own flesh and blood; his punishment, to be obliged continually to do them injury.
Such in outline is the religion of the Ostiaks, whom the Greek Catholics despise as heathen. But a just estimate of these honest people, with their child-like nature, inclines us rather to wish that they may ever remain heathen, or at least may never be other than they are.
THE NOMAD HERDSMEN AND HERDS OF THE STEPPES.
Though the steppe of Central Asia is really rich, and may even seem gay to one who visits it in spring, and though it contains much fruitful land, it is nevertheless only its most favoured portions which admit of a settled life, of a continued residence on any one particular spot. Constant wandering, coming and going, appearing and disappearing, is the lot of all the children of the steppe, men and animals alike. Certain portions submit to the labours of the husbandman; in others, towns and villages may be established, but the steppe as a whole must for ever remain the possession of the nomadic herdsman, who knows how to adapt himself to all its conditions of life.
Among these nomadic herdsmen the Kirghiz take the first rank, by virtue both of numbers and of civilization. Their domain extends from the Don and the Volga to the mountains of Thianshan, and from the middle Irtish to south of the Balkhash Lake, indeed, almost to Khiva and Bokhara; they are divided into tribes and hordes, into steppe and mountain herdsmen, but they are one in descent, in language and religion, in manners and customs, however much the various tribes may appear to differ. The smallest or youngest horde wanders throughout the steppe of Orenburg; a branch of the same, calling itself the Buka tribe, traverses the steppe between the Volga and Ural rivers, especially in the governments of Turgai and Ural; the middle or elder horde inhabits the steppes and mountains of the Irtish and Balkhash regions; and finally, extending from beyond the river Ili towards Khiva and Bokhara are to be found the everchanging dwelling-places of the mountain Kirghiz, who describe themselves as the great, or eldest horde. No branch of these people applies the name Kirgis or Kirghiz to itself, for that is a term of infamy
equivalent to “freebooters”. The proper designation of our people is Kaisak, Kasak, or, as we should read it, Cossack, although even the Russians apply the name Cossack to a people quite distinct from the inhabitants of the steppe.
The Kirghiz, as I shall call them nevertheless, are a Turkish people, about whose racial affinities different opinions are held. Many, if not most, travellers look upon them as true Mongolians, while others regard them, probably more correctly, as a mixed race, suggestive of the Mongolians in some particulars, but, on the whole, exhibiting the characteristics of Indo-Germans, and especially resembling the Turkomans. All the Kirghiz I saw belonged to the middle horde, and were well-built people, small, or of medium height, with faces, not beautiful indeed, but not of the caricature-like Mongolian type, neat hands and feet, clear or transparent light-brown or yellowish complexions, brown eyes, and black hair. The cheek-bones are seldom so prominent, or the chin so pointed, as to give an angular or cat-faced appearance; the eye, of medium size, is usually most arched centrally, and drawn out horizontally at the outer angle; it is thus almond-shaped, but not obliquely set; the nose is usually straight, more rarely hooked; the mouth moderate in size and sharply cut, the beard thin, without being actually scanty. True Mongolian features are certainly to be met with also, more especially among the women and children of the poorer class; but, though I have seen very few really beautiful Kirghiz women, I have met with quite as few of the grotesque faces so common among other undoubted Mongols. The characteristics are unmistakably more suggestive of a mixed race than of any one sharply defined stock. I have seen men whom I should unhesitatingly have pronounced to belong to the nobler Indo-Germans if I had known nothing of their kinship, and I have become acquainted with others about the Mongolian cut of whose faces there could be no possible doubt. The members of the older families usually possess all the essential marks of the IndoGermans, while men of lower descent and meaner extraction often remind one of the Mongols in many details, and may sometimes resemble them completely The power of Islam, which permits to slaves who have become converts all the rights of the tribe, may in the course of time have made Kirghiz out of many heathen Mongols,
and thus not only have influenced, but actually destroyed the racial characteristics of the Kirghiz.
Although the chief features of the Kirghiz dress are Turkish, it is, as a whole, by no means suited for displaying their figure to advantage. In winter the fur cap, fur coat, and thick-legged boots hide all the details of the figure, and even in summer these do not come into prominence. The poorer Kirghiz, in addition to his fur coat and the inevitable fur cap, wears a shirt, kaftan, and wide trousers; the higher class rich man, on the other hand, wears a great many articles of dress one above the other, like the Oriental; but he stuffs all those which envelop the lower part of his body, with the exception of his fur coat, into his wide trousers, so that he may not be impeded in riding. Consequently, the more richly attired he is the more grotesque he looks. They prefer dark colours to light or bright ones, though they do not despise these, and they are fond of decorations of gay embroideries or braiding. Nearly every Kirghiz wears at his girdle a dainty little pocket, richly decorated with iron or silver mountings, and a similarly ornamented knife; beyond these, and the indispensable signet-ring, he wears no decoration unless the Emperor has bestowed one upon him, in the shape of a commemorative medal.
Of the dress of the women I can say little, first, because modesty forbade me to ask about more than I could see, and secondly, because I did not see the women of the upper class at all, and never saw the others in their gala attire. In addition to the fur coat, boots and shoes, which are exactly like those of the men, the women wear trousers which differ very slightly, a shift, and over it a robe-like upper garment, falling below the knee and clasped in the middle; on the head they wear either a cloth wound in turban-fashion, or a nunlike hood which covers head, neck, shoulders, and breast.
The clothing of both sexes is coarse, except the riding-boots and shoes, which are always well made. Very characteristic, and obviously adapted to the climatic conditions, are the extraordinarily long sleeves which both men and women wear on their upper garment; these fall far beyond the hands, and cover them almost completely.
Fig. 66. The Home of a Wealthy Kirghiz.
The roving life to which the Kirghiz are compelled by the necessity of finding sufficient pasturage for their numerous herds, involves a style of dwelling which is easily constructed, can be taken down at one spot and erected again at another without special difficulty, and which must yet afford a sufficient protection against the hardness and inclemency of the climate. These requirements are fulfilled more thoroughly by the yurt than by any other movable dwelling, and it is not too much to say that this is the most perfect of all tents. Thousands of years of experience has made the yurt what it is—a home for the nomadic herdsman, or any other wanderer,—which, in its own way, cannot be surpassed. Light and easily moved, readily closed against storms, or thrown open to admit air and sunshine, comfortable and commodious, simple, yet admitting of rich decoration without and within, it unites in itself so many excellent qualities that one appreciates it ever more highly as time goes on, and finds it more and more habitable the longer one lives in it. It consists of a movable lattice-work which can be extended or contracted, and which forms the lower upright circular walls of the framework, a coupling ring which forms the arch at the top, spars
inserted into both these, and a door in the lattice-work; light mats of tschi-grass, and large wads or sheets of felt, cut to shape, and most ingeniously laid on, compose the outer covering of the whole framework, and thick carpets of felt cover the floor. With the exception of the door-frames, which are mortised together, and of the spars, the upper ends of which are inserted into holes in the coupling-ring, the whole structure is held together simply by means of cords and bands; and it is thus easily taken to pieces, while its form—circular in cross section, and cupola-like longitudinally— renders it capable of great resistance to violent storms and bad weather of all sorts. The work of putting it up scarcely requires more than half an hour, that of taking it down even less; the strength of a single camel conveys it from place to place, but its construction and decoration take up much of the time and all the ingenuity of the housewife, to whose share falls the chief work of making it, and the whole labour of setting it up.
The yurt forms an important part of the movable property of a Kirghiz. A rich man owns six or eight, but he spends money rather on the decoration of a few than on the construction of many, for he is assessed and taxed not according to the size of his herds but the number of his yurts. The high-class Kirghiz certainly shows his wealth through his yurt, by fitting it up as richly as possible, making it out of the most valuable felt, and decorating it without and within with coloured pieces of cloth; but he sets store rather by the possession of costly rugs, and beautifully sewn and embroidered silken coverlets, with which he decorates the interior of the living-room on festive occasions. Such rugs are handed down from father to son, and the possession of them ranks scarcely below that of uncoined silver.
The real wealth of the nomadic herdsman cannot, however, be estimated by such secondary things; it must be calculated by his herds. Even the poorest owner of a yurt must possess numerous beasts to enable him to live, or survive in the struggle for existence; for the herds he tends form the one indispensable condition of life; they alone stand between him and ruin. The rich man’s herds may number thousands upon thousands, those of the poor man at least
hundreds; but the richest may become poor, if disease breaks out among his herds, and the poor man may starve if death visits his beasts. Wide-spreading murrain reduces whole tribes to destitution, causes thousands of human beings literally to die of starvation. Little wonder, then, that every thought and aspiration of the Kirghiz is bound up with his herds, that his manners and customs correspond to this intimate connection between man and beast, that the man is, in short, dependent on the animal.
Not the most useful, but the noblest and the most highly prized of all the domesticated animals of the Kirghiz is the horse, which in the eyes of its owner represents the sum and essence of domestication, and the climax of all beauty; it is a standard by which to reckon, according to which wealth or poverty is determined. He does not call it a horse, but simply the domestic animal; instead of the words “left and right” he uses the expressions, “the side on which one mounts a horse”, and “the side on which one carries the knout”. The horse is the pride of youth and maiden, of man and woman, whether young or old; to praise or find fault with a horse is to praise or blame its rider, a blow given to a horse one is not riding is aimed not at the horse but at its owner.
A large number of the Kirghiz songs refer to the horse; it is used as a standard of comparison to give an estimate of the worth of men and women, or to describe human beauty.
“Little bride, little bride, Dear foal of the dark brood-mare!”
the singer calls to the bride who is being led into the bridegroom’s yurt;
“Say where is the play of the white locks And where the play of the foals, For kind as is the new father, He is not the old father to me,”
the bride answers to the youths who sing the “Jarjar”, the song of consolation to the departing bride, referring by the words “Foal-play” to the time of her first love.
The wealth of a man is expressed in the number of horses he possesses; payment for a bride is made in the value of so many horses; the maiden who is offered as a prize to the winner in a race is held as being worth a hundred mares; horses are given as mutual presents; with horses atonement is made for assassination or murder, limbs broken in a struggle, an eye knocked out, or for any crime or misdemeanour; one hundred horses release from ban and outlawry the assassin or murderer of a man, fifty, of a woman, thirty, of a child. The fine imposed by the tribe for injuring any one’s person or property is paid in horses; for the sake of a horse even a respectable man becomes a thief. The horse carries the lover to his loved one, the bridegroom to the bride, the hero to battle, the saddle and clothing of the dead from one camping-place to another; the horse carries man and woman from yurt to yurt, the aged man as well as the child firmly bound to his saddle, or the youthful rider who sits for the first time free. The rich man estimates his herds as equivalent to so many horses; without a horse a Kirghiz is what a man without a home is among us; without a horse he deems himself the poorest under the sun.
The Kirghiz has thoroughly studied the horse, he knows all its habits, its merits and defects, its virtues and vices, knows what benefits and what injures it; sometimes, indeed, he expects an incredible amount from it, but he never exacts it unless necessity compels him. He does not treat it with the affectionate care of the Arab, but neither does he ever show the want of consideration of many other peoples. One does not see anything of that careful and intelligent breeding of horses which is practised by Arabs and Persians, English and Germans, but he does constantly endeavour to secure the improvement of his favourite breeds by only placing the best stallions with the mares, and castrating the rest. Unfortunately his choice of breeding-horses is determined solely by form, and does not take colour into consideration at all, the consequence being that many of his horses are exceedingly ugly, because their colouring is so irregular and unequal. The training of the horse leaves much to be desired; our wandering herdsman is much too rich in horses for this to be otherwise.
We found the Kirghiz horse a pleasant and good-natured creature, although it by no means fulfilled our ideal of beauty in all respects. It is of medium size and slender build, with a head not ugly though rather large, decidedly ram-nosed, and noticeably thickened by the prominent lower jaw-bones, a moderately long and powerful neck, a long body, fine limbs, and soft hair. Its eyes are large and fiery, its ears somewhat large, but well-shaped. Mane and tail have fine, long hair, always abundant, the hair of the tail growing so luxuriantly that it sweeps the ground; the legs are well formed, but rather slim, the hoofs are upright, but often rather too high. Light colours prevail and very ugly piebalds often offend the eye. The commonest colours are brown, light-brown, fox-coloured, dun, and bay, more rare are darkbrown and black, and one only occasionally sees a gray. The mane and tail greatly increase the beauty of all the light-coloured horses, because they are either black or much lighter than the body hairs.
The temper of the animal is worthy of all praise. The Kirghiz horse is fiery, yet extremely good-natured, courageous in the presence of all known dangers, and only nervous, skittish, and timid when it is bewildered for a moment by something unusual; it is spirited and eager in its work, obedient, docile, willing, energetic, and very enduring, but it is chiefly valuable for riding, and requires long breaking-in to make it of use as a draught animal, in which capacity it is much less valuable than as a riding-horse.
