A Complete Guide on Carbon Composition Resistors, Fixed Value Resistors

There are two major types of resistors, linear and nonlinear. The current production is linearly proportional to the applied voltage in linear resistance. As voltage changes, the current also changes. Nonlinear resistors are those where there is no effect of any change in applied voltage on the producing current. In variable resistors, the resistance value may change according to requirements, whereas in fixed value resistors, the value of resistance remains constant as per the manufacturer’s end. Carbon Composition Resistors are fixed value resistors that carry a specific weight that you can not change anywhere in the circuit operations. More examples of fixed value resistors are wire wound resistors , thick and thin-film resistors.

Negative Temperature Coefficient

Carbon composites have a significant negative temperature coefficient, making them highly temperature-sensitive. Carbon compounds with high resistance values (1 Megohm and more significant) can shift by up to 20% at -55 °C and -14% at +105 °C. Due to instability, carbon composites are inappropriate for many of today’s precise electronics.

Carbon Composition Resistors

Carbon Composition Resistors are fixed value resistors containing a cylindrical resistive substance. Both ends have embedded metal wires or lead attached with metal caps. The body has a coated shelter of paint or plastic. It is to protect the device from external moisture and other damages.

Carbon composite, or carbon comp, is a fixed resistor that opposes or interrupts the electricity flow to a fixed point. The resistance of this resistor is primarily determined by three factors: the amount of carbon present, length and cross-sectional area of a solid cylindrical rod.

Resistor Design Based on Carbon Composition

A mixture of powder carbon and ceramic in a certain ratio is meant to be the best resistive compound. To construct a Carbon Composition Resistor, take this mixture and bake it into a cylindrical form. Put meta caps on both ends. Connect metal leads to these on both metal caps. Paint the middle body or wrap it with plastic to keep it safe from external damage. This resistor may be colour-coded using paint.

To count the resistance value on a specific Carbon Composition Resistor, you can use the ratio between the filling material and the used carbon. It is an excellent conductor when high carbon concentrations result in lower resistance. When these resistors are exposed to high voltages, their value will alter. The heat produced during soldering will likely alter the resistance value that can not be reversed. To avoid this flip in resistance value exposure, Internal content in a moist environment, for instance, is quite essential. The resistance values for Carbon Composition Resistors are fixed by the manufacturers’ end during the designing of the resistors. Hence you can say that Carbon Composition Resistors are fixed value resistors.

The Purpose of Using Carbon

You can use different materials for Carbon Composition Resistor fabrication, but carbon is a versatile component and has been used for several years. Carbon resistors are robust; they do not damage so frequently. Alternatively, you can say these are long-lasting. Moreover, they efficiently work in high energy states.

Carbon resistors come in two different types: carbon composition and carbon film. To make them more durable, you could use graphite and clay additives in their construction. These are now employed in relatively few applications due to their high cost and lack of reliability in high moisture environments.

Carbon film resistors have been popular among electronics consumers in the past few years. A layer of the carbon film is imposed on an insulating substance. Ceramic is the most common insulating material best suited for this resistor’s making. Carbon film resistors are not an excellent choice for high voltage uses. These are cheaper in comparison to carbon composition resistors. The major disadvantage of carbon is its strong negative temperature coefficient.

Meaning of Fixed Value Resistors

Fixed resistors are resistors that have a predetermined resistance value. Set resistors have a fixed resistance that will not change. This resistance is unaffected by voltage or temperature. Wire wound resistors, thick film resistors, thin-film resistors and Carbon Composition Resistors are fixed value resistors.

Conclusion

Because of the features described above, resistors such as carbon-film resistors and carbon composition based resistors are excellent for appropriate applications in electrical circuits. Since electronic circuits employ shallow currents, such resistors are safe and worth it. However, you cannot use these resistors for every circuit due to limitations, such as the negative temperature coefficient. However, they are well-known for their tiny size and low cost. As Carbon Composition Resistors are fixed value resistors, they carry a non-adjustable fixed value of resistance