Electronic – Is a switch considered an active component


Most of the definitions of "active" components that I have found define them as components able to control current flow. A switch fits this definition, but I am just curious to see opinions on this.

Best Answer

A switch is a passive component.

The main difference between active and passive, is that active components require a power source to perform their function, i.e. using electricity to control electricity as in a transistor. They can be a source of power in the circuit or provide an electrical switching function. They can provide amplification, whereas a passive component cannot.

So Valves(Tubes), Transistors, SCRs, LEDs, Diodes, ICs, etc are all active devices.

Passive devices are things like Resistors, Capacitors, Inductors, Transformers, Thermistor, Speaker, Microphone, etc.

To be honest I think the definition is a bit muddy, and I've never seen a formal definition that satisfies me completely, but the above is the usual sort of answer. For example, take the diode - this often causes a bit of debate on how it should be classified (I think it probably has to be an active device) Either way I think it doesn't really matter much as long as you get the general idea.