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Question
What are the readings of the ammeters A1 and A2 shown in figure. Neglect the resistance of the meters.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
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Solution
From the circuit diagram, we can see that one diode (the upper one) is reverse biassed.
We know that when a diode is forward biassed, it has zero resistance ideally. So, it can be replaced by a short circuit. When a diode is reverse biassed, it has infinite resistance ideally. So, it can be replaced by an open circuit.
Thus,
In the given circuit, one diode is reverse biassed. So, it can be replaced by an open circuit. Hence, the current in this branch will be zero.
So, the current through A1 is zero.
For A2,
Current = \[\frac{2}{10}\] = 0.2 A
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