Question

In the given circuit, if the diode D2 is a Germanium diode and all other diodes are Silicon diodes, then which of the following statements is true?

(a) ID2 < ID3; ID2 = ID1

(b) ID2 > ID3; ID2 > ID1

(c) ID2 > ID3; ID2 = ID1

(d) ID2 > ID3; ID2 < ID1

The question was posed to me during an interview for a job.

My query is from Parallel and Series Configuration in chapter Diode Circuit of Analog Circuits

Answer 1

The correct option is (c) ID2 > ID3; ID2 = ID1

Easiest explanation: Voltage across the parallel diodes = 0.3 V. Hence, current through D3 = 0. Hence ID2 > ID3. Also, as both the parallel silicon diodes are in parallel and in off-state, the diodes 1 and 2 are in series and hence, current through them is same.