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I think diode is a passive device because it always dissipated power. The current-voltage characteristics of the diode are always on the 1st and 3rd quadrant so that that the instantaneous power dissipation (i*v) is always positive.
Diode is consider as active component because it requires supply to voltage to be forward biased and perform its function as a switch or as a rectifier unlike resistor/capacitor/inductor which do not need any voltage to turn on/off. We defined active component when it require external supply voltage to perform function while passive component do not need supply voltage
Diode does not consume any power? Are you kidding?
The diode has a forward voltage when you forward bias it and that produces a power loss -- that is why it is a passive device. The current-voltage product of a diode is always positive -- it always dissipates power.
Take a look at a simple diode, it will have a forward voltage of 0.7-1.0V. Let's say you are putting 1A through it. Everytime you do this you have an instantaneous power dissipation of 0.7-1.0W. Now usually diodes are used in circuits where they are not always passing current. In that case, you can take the power dissipation versus time and calculate the average power dissipation.