Resistors(194141)

Definition:

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of electrical power as heat may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.

Types of Resistor:

Fixed resistors are designed to set the right conditions in a circuit. Their values should never be changed to adjust the circuit since those were determined during the design phase. It can have a carbon composition or chip-and-wire wound type. It can also be made with a mixture of finely ground carbon or be very small in size and for high power rating.

Variable resistors have fixed resistor elements plus a slider. The slider taps onto the main resistor element so there will be three connections; two are connected to the third element and one to the slider. Examples of this are potentiometers, rheostats, trimmers, and so on.