A 2V battery may be connected across the points A and B as shown in figure. Assume that the resistance of each diode is zero in forward bias and infinity in reverse bias.Find the current supplied by the battery if the positive terminal of the battery is connected to (a) the point A (b)the point B.

Explanation

(a). When the positive terminal of the battery is connected to the point A, the diode `D_(1)` is forward-biased and `D_(2)` is reverse-biased. The resistance of the diode `D_(1)` is zero, and it can be replaced by resistanceless wire. Similarly the resistance of the diode `D_(2)` is infinity and it can be replaced by a broken wire. The equibalent circuit is shown in the figure. The current supplied by the battery is `2 V//10 Omega=0.2A`
(b). When the positive terminal of the battery is connected to the point B, the diode `D_(2)` is forward-biased and `D_(1)` is reverse blased. The equivalent circuit is shown in figure (b). The current through the battery is `2 V//20 Omega=0.1A`