Diodes and their applications

Explanation of question 5

In the circuit in Fig. 13.1, the ammeter indicates a current starting to flow when the voltmeter reads 0.6V. The junction diode will be

1. germanium, forward-biased
2. germanium, reverse-biased
3. silicon, forward-biased
4. silicon, reverse-biased

The answer is :- 3 With the polarity given, the junction diode is forward-biased. A voltmeter reading of 0.6 V would indicate a silicon diode. The reading for a germanium diode would be about 0.1 V.