active & passive device

Why inductor, capacitor and resistor are called passive device, while transistor, diode and FET are call active device!!

any response will be highly appreciated! thanx!

Reply to
Te-Jung Lo
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A diode is not an active device. It does not perform any active function.

Reply to
Gym Bob

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Transistors and FET's require a source of energy for thier operation and have outputs that are a function of input signals.

Resistors, capacitors, inductors and diodes are devices that do not require a source of energy for thier operation.

Dave M.

Reply to
Dave M.

in article snipped-for-privacy@free.teranews.com, Gym Bob at snipped-for-privacy@nospam.com wrote on 6/27/03 7:30 PM:

The distinction between passive and active devices is not always that simple.

Consider a tunnel diode or certain thermionic diodes. Under certain conditions, they can be turned into oscillators. What about an SCR? Once turned on it is about as active as any other switch. Even passive componets such as resistors and inductor do their work only if supplied with power.

Bill

Reply to
Repeating Decimal

I don't know that I agree with that. An LED is a diode with an active state and an inactive state. There are cases that a standard diode performs the same faction under control. I really believe that circuit level should decide active components vs. passive components. Not the components them selves.

Reply to
Mark

When a diode is considered "inactive", does that make it a passive device? If that were the case, would that not mean that every xsistor when turned off becomes a passive device?

Passive devices are things such as coils, resistor, capacitors. I have never personally heard of anyone calling a diode passive.

Reply to
C What I Mean

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