So a resistor is an active device because the current is controlled by the voltage (and vice-versa, for that matter).Anything that is controlled by current or voltage is active device in my book.
If I apply more voltage I get more current.Resistor controls the current,its resistance
doesnt change if you apply more voltage to it..Its dependant on temperature.
By applying more voltage you will get more current not more resistance. So you can't change the original value of resistor to some other resistance by applying more voltage.And key purpose of resistor is to provide set resistance which wont change dependently on voltage or current.If I apply more voltage I get more current.
Since current qualifies as a subset of "anything", we have an "anything" being controlled by a voltage, which satisfies your definition of an active device.
But your definition, namely, "Anything that is controlled by current or voltage is active device," does not say that "anything" has to be restricted to the resistance of a resistor. Your definition says that it is an active device if "anything" is controlled by either current of voltage. Are you claiming that current through a resistor is not "anything"? If so, then what is and is not an "anything"?By applying more voltage you will get more current not more resistance. So you can't change the original value of resistor to some other resistance by applying more voltage.And key purpose of resistor is to provide set resistance which wont change dependently on voltage or current.
Do you change any of the junctions in a transistor from PN to NP or vice-versa if you apply more voltage across it? No. So now you would seem to be saying that a BJT is not an active component.It shouldn't be able to change the original purpose of the component. Do you change the resistance of the resistor if you apply more voltage to it?No. Do you change the diode junction from PN to NP if you apply more voltage across it?No.
I can just imagine.Wow!!! this discussion takes me back to when I was working on the engine control computers (analogue) for Concorde. I had to write a report about any failed components. A diode was leaky and I described it as active because at the time, my view was, as it was essential that it only conducted when forward biased, it was "actively" operating. However, I was reprimanded by a senior technician who claimed it was passive. This started a long and drawn out discussion amongst all of us and we eventually agreed it was dependent on its application. But then we could not agree on which applications were active or passive???? and so it was never really resolved.
Understand. Please note that I am not trying to be contrary just for contrariness sake, but rather trying to help you solidify a "fluffy" definition into something that is more defensible.I'm just not going to say anything because this discussion can go to infinity and beyond.
Cheers!
What do you mean by signal?My definition of a passive device is one that only consumes power (attenuates the signal) and doesn't alter the signal. By this definition, a diode is definitely active, since it significantly alters the signal.
That animal is a sloth.Understand. Please note that I am not trying to be contrary just for contrariness sake, but rather trying to help you solidify a "fluffy" definition into something that is more defensible.
Aside: What is the critter in your avatar? I know I've seen it before, but nothing comes to mind.
What is going into the device. Maybe I should have used "waveform".What do you mean by signal?
by Jake Hertz
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