The I – V characteristics of the zener diodes D1 and D2 are shown in Figure I. These diodes are used in the circuit given in Figure II. If the supply voltage is varied from 0 to 100 V, then breakdown occurs in.

The I – V characteristics of the zener diodes D1 and D2 are shown in Figure I. These diodes are used in the circuit given in Figure II. If the supply voltage is varied from 0 to 100 V, then breakdown occurs in. Correct Answer D1 only

Breakdown voltage of D₁ = 80V

Breakdown voltage of D₂ = 70V

When V_in exceeds 80V then D₁ is in breakdown region, then circuit becomes

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∴ D₂ never get a chance to enter into breakdown region

(∴ V_inmax = 100V then V_D2 = 100 – 80 = 20 < V_breakdown)

∴ so only D₁ enters into Breakdown region.