Construction of carbon composition resistors

The carbon composition resistor is a type of fixed resistor that reduces or restricts the electric current flow to a certain level.

carbon composition resistor

The basic construction of carbon composition resistor is shown in above figure. The resistive material is of carbon clay composition. For manufacturing the carbon composition resistor the raw material is used are carbon black, resin binder and refractory fillings. Before mixed in proper proportion to produced desired value of resistance and shifting, these raw materials are graded first. The resultant black powdered is then compressed into the shape of a resistor and then cured in an oven to solidify the units. Basically a simple rod of carbon power is the resistance element. The resistance element is enclosed in a plastic case for insulation and mechanical strength. With the leads of tined core two ends of the carbon resistance element are joined to metal caps. These two leads are provided for soldering the resistor into the circuit.