Topic summary
Passive filter
Extracted from the Wikipedia article Passivity (engineering).
Passive filter
A passive filter is a kind of electronic filter that is made only from passive components – in contrast to an active filter, it does not require an external power source (beyond the signal). Since most filters are linear, in most cases, passive filters are composed of just the four basic linear elements – resistors, capacitors, inductors, and transformers. More complex passive filters may involve nonlinear elements or more complex linear elements, such as transmission lines.