Measuring Electricity Master

Measuring Electricity

Multimeters are tools used to measure electricity. The multimeter allows you to measure current, resistance, and voltage, and displays the reading numerically. When using a multimeter it should be noted that some measurements will never “stay still” at a single repeatable value. This is the nature of the variables being monitored in some circumstances. For example, if you were to measure the resistance between your two hands with the ohmmeter setting on the multimeter (megohm range—millions of ohms), you would find that the values would continuously change. How tightly you squeeze the metal probes and how “wet” or “dry” your skin might be can have a sizable effect on the reading that you obtain. In this situation you need a protocol or standardized method to allow you to record data. We recommend that you discuss with your class the variability of measurement and let them come up with a standard for collecting data. They may decide to go with the lowest reading, the highest reading, or the reading that appears most frequently in a certain time period.

Digital Multimeter

(NOT USED)

Directions

DC VOLTAGE

1. Connect RED lead to VΩmA jack and BLACK to COM. 2. Set ROTARY SWITCH to the highest setting on the DC VOLTAGE scale (1000). 3. Connect leads to the device to be tested using the alligator clips provided. 4. Adjust ROTARY SWITCH to lower settings until a satisfactory reading is obtained. 5. With the water turbine, usually the 20 DCV setting provides the best reading.

DC CURRENT MUST INCLUDE A LOAD IN THE CIRCUIT - NOT NECESSARY FOR THESE ACTIVITIES 1. Connect RED lead to VΩmA jack and BLACK to COM. 2. Set ROTARY SWITCH to 10 ADC setting. 3. Connect leads to the device to be tested using the alligator clips provided.

Note: The reading indicates DC AMPS; a reading of 0.25 amps equals 250 ma (milliamps).

YOUR MULTIMETER MIGHT BE SLIGHTLY DIFFERENT FROM THE ONE SHOWN. BEFORE USING THE MULTIMETER, READ THE OPERATOR’S INSTRUCTION MANUAL INCLUDED IN THE BOX FOR SAFETY INFORMATION AND COMPLETE OPERATING INSTRUCTIONS.