A Handful of Information About the CCR or Carbon Composition Resistor Do you know what is a CCR or Carbon Composition Resistor? CCR or carbon composition resistor encompasses a solid rod of conductive composition materials that could be changed to generate different resistance values. The general composition contains these elements: -
1 Conductor - Carbon
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1 Filler - Ceramic
By modifying the ratio of filler to conductor it is easy to change the resistance value. There are interference-fit end caps that are connected to the rods, leads are welded onto the said caps and then a specially formulated epoxy covering will be used to protect the resistor body. Then lastly; the resistors will be color code marked. Generally, the CCR already has been around hundred years ago. Through the beginning of the 20th century, resistors were being created without the presence of coating. The lead wires were directly soldered to the resistor’s body. Till the 1960’s, there have been only two kinds of resistors available, namely: wire-wound and carbon composition resistors. In the 1960s and 70s there seemed to be a shift in the use of carbon composition resistors to other forms just like the carbon film or metal film resistor. Advantages and Disadvantages Their capability to withstand high energy pulses is the most essential benefit from carbon composition resistors. Once the current passes through the resistor, the carbon composition body can actually dissolve the energy. Let’s take the Wirewound resistors as an example. This resistor has a much smaller volume of wire to dissipate the energy. Therefore, the thermal mass of the CCR is a lot greater, producing a greater energy pulse capability. On the other hand, carbon composition resistors are created with a much higher resistance than wire wound. This type is likewise less expensive as compared to the other. However like in all kinds of resistors, CCR have its own drawbacks. Its properties, for example, aren’t so good when it comes to temperature coefficient, noise and voltage dependency and load. Furthermore, the carbon composition resistors have the capacity to resist high energy pulses despite of its small size. For the very same reason the carbon composition resistor remains to be used in numerous modern day applications. Applications range from the proper protection of circuits (surge or discharge protection), current restricting, high voltage power supplies, high power or strobe lighting, and welding. More Applications CCR are suitable for any application concerning high-energy pulses, where small size is important. These are generally a viable alternative to hot moulded carbon resistors. Even though many carbon composition resistors have now been replaced by other technologies (carbon-film, metal-film and
wirewound in particular), these solutions aren't always suitable, and there continue to be applications where carbon composition resistors are utilized, normally when there are high pulse performance specifications. You'll also find applications in which there is a need for resistors with very low inductance. The most effective way to acquire this is to determine a carbon composition type, in which the resistive component is a homogeneous block of carbon, to ensure that component inductance is principally due to the leads. Presently, there are already ceramic-carbon types that outdated the carbon compositions that uses a carbon conductor mixed with ceramic filler instead of a hot-molded solid carbon block. Then again, the resistance value could be modified by altering the ratio of filler to conductor. Additionally, a special non-inductive metal film or foil resistors can be used for more demanding requirements. Source: http://www.resistorguide.com/carbon-composition-resistor