active devices and passive devices

i'm looking at the definition for active device

"active device: A device that requires a source of energy for its operation and has an output that is a function of present and past input signals. Note: Examples of active devices include controlled power supplies, transistors, LEDs, amplifiers, and transmitters."

what active device has a power source but its output is not a function of its input signals? Also. An LED doesn't even have input signals does it???!!! I can't see why it fits into that definition of active device.


Reply to
James Hanley
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An active device is any type of circuit component with the ability to electrically control electron flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device. Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices. Active devices include, but are not limited to, vacuum tubes, transistors, silicon-controlled rectifiers (SCRs), and TRIACs.

H> i'm looking at the definition for active device


Reply to

On 2 Mar 2005 10:58:24 -0800 in sci.electronics.basics, (James Hanley) wrote msg :

You've stumbled into an ongoing debate. I agree (as I think most in the industry do) with "aman"'s description, but you'll find other sources that will group diodes as active devices. Don't worry too much about it.

Al Brennan
Reply to
Kitchen Man

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