A 3V battery may be connected across the point A and B as shown in Fig. Assume that the resistance of each diode is zero in the forward bias and infinity in the reverse bias. Find the current supplied by the battery if the positive terminal of the battery is connected to the point A the point B.

Explanation

When the positive terminal of battery is connected to the point A, the diode `J_(1)` is forward biased and `J_(2)` is reversed biased. Therefore the resistance of diode `J_(1)` is zero and that of `J_(2)` is infinity. No current flows through `J_(2)`. Thus, `J_(1)` can be replaced by resistanceless wire and `J_(2)` can be replaced by broken wire. The equivalent circuit will be as shown in Fig. The current in the circuit,

`i=3/10=0.3A`
When positive terminal of the battery is connected to terminal B, the diode `J_(1)` is reverse biased and `J_(2)` is forward biased. The equivalent circuit will be as shown in Fig. The current in the circuit is, `i=3//30=0.1A`.