diodes works both on ac and dc.
ex.
1.
it is used in polarity sensitive dc circuits for protection -
it means, some dc circuits needs to connect positive dc supply to positive terminal of the circuit and negative to negative.
if you interchange the polarity, the circuit will be damaged.
here, if you connect DC supply through a diode, it will only conduct current when it is forward biased - means, when you connect the polarities correctly to the circuit.
otherwise it will block the current, protecting the circuit from reverse polarity connection.
2.
using zener diodes as a voltage referance -
by placing a zener diode parallel to the circuit, you can get a reference voltage.
3.
and of course LED (light emitting diodes)
hope this helped you
Diodes will work in either AC or DC circuits.
NO, DIODE CAN BE USED ON BOTH DC OR AC .
