An ideal diode is a two terminal device with symbol
and characteristics as shown below.
Ideal
diode will conduct current from A to K and acts like an
open circuit to any attempt to establish current from K to A.
As shown in characteristics
(red) ,when diode conducts from A to K, the voltage drop (VD) across
it is zero i.e the diode acts like a short circuit. The magnitude of current is
limited by the circuit resistance. diode
resistance = 0 in this mode of
operation.
If a negative voltage is applied across an ideal
diode, it acts like an open circuit i.e ID =0 , evident from the black
colored characteristics. diode resistance = ∞
in this mode of operation.
Both the above conclusions from characteristics are illustrated
below.
Power Loss (zero)
:-
Ideal devices does not dissipate energy. The property
is satisfied by an ideal diode also.
Power loss = voltage × current = VD × ID
In first quadrant operation, VD = 0 and ID ≠ 0 , therefore, power loss = 0
In third quadrant operation, VD ≠ 0 and ID = 0 , therefore,
power loss = 0
So, an ideal diode does not consume any power in both
forward conduction and reverse blocking mode.
