A full-wave centre-tapped rectifier with diodes D₁ and D₂ is shown. Its input voltage is Vᵢₙ = 220 sin(100πt) V. At t = 15 ms, which diode is forward biased? Image
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Question

A full-wave centre-tapped rectifier with diodes D₁ and D₂ is shown. Its input voltage is Vᵢₙ = 220 sin(100πt) V. At t = 15 ms, which diode is forward biased? Image

G1 Physics · Accepted Answer

Step 1: Substitute t = 15 ms = 0.015 s into the applied sinusoid. Step 2: Phase = 100π × 0.015 = 1.5π = 3π/2. Step 3: Vᵢₙ = 220sin(3π/2) = −220 V, i.e. the transformer secondary polarity reverses relative to the positive half-cycle. Step 4: With the diode orientations in the centre-tapped rectifier diagram, negative input makes D₁ reverse biased and D₂ forward biased. Final answer: D₁ reverse and D₂ forward, Option B.