A passive electronic component is a component that consumes but does not produce energy and is incapable of power gain and does not require electrical power to operate. They absorb energy without creating any active gain and are present in most electrical items.
Examples of passive electronic components are chassis, capacitors, resistors and enclosures. Let’s look into these a bit more.
Resistor – A resistor, as its name would suggest, resists the flow of a current through a circuit. The end result is a voltage drop with the power being absorbed within the device. Resistors help dissipate heat.
Capacitor – A capacitor is a pair of conductors which are separated by a dielectric (insulator). The voltage is applied and a field is created which stores energy between conductors. These are used for a number of reasons such as smoothing DC circuits, power storage, signal coupling, decoupling, noise filling and tuning circuits.
Transformer – Transformers are electrical devices which use electromagnetic induction to transform electrical energy from one or more circuits to one or more other circuits at the same frequency but usually a different voltage or current value.
Passive components can be divided into two types. The first is lossy or dissipative, which does not have the capacity to absorb power from an external circuit over a period of time such as a resistor. The second is lossless which does not have an input or output net power flow such as indicators, capacitors, transformers and gyrators.
Active devices meanwhile control the flow of electrons through them. Some allow voltage to control this current while other devices allow another current to do the job.