Choose the incorrect statements from the options given below:
(A) In making a full wave rectifier, the two diodes are connected, with one in forward bias and the second in reverse bias.
(B) In a full wave rectifier, the output frequency is twice the input frequency.
(C) In a full wave rectifier, the current through the load resistance flows in one direction for half cycle and in the reverse direction for the other half cycle.
(D) In a full wave rectifier having two diodes and a resistance, the output voltage is uniform.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (C) and (D) only
In a centre-tap full wave rectifier the two diodes conduct in alternate half cycles, and both send current through the load in the same direction.
(A) In making a full wave rectifier, the two diodes are connected, with one in forward bias and the second in reverse bias. — Correct. At any instant one diode is forward biased and the other reverse biased.
(B) In a full wave rectifier, the output frequency is twice the input frequency. — Correct. There is one output pulse in every half cycle, so the pulses repeat at \( 2f \).
(C) In a full wave rectifier, the current through the load resistance flows in one direction for half cycle and in the reverse direction for the other half cycle. — Incorrect. The load current flows in the same direction in both half cycles; that is what rectification means.
(D) In a full wave rectifier having two diodes and a resistance, the output voltage is uniform. — Incorrect. The output is pulsating dc; a filter (a capacitor across the load) is needed to make it nearly steady.
NCERT (2026-27):
Application of Junction Diode as a Rectifier – “… Each diode rectifies only for half the cycle, but the two do so for alternate cycles.”
Application of Junction Diode as a Rectifier – “… So, diode D1 gets forward biased and conducts (while D2 being reverse biased is not conducting). … Thus, we get output voltage during both the positive as well as the negative half of the cycle. … The rectified voltage is in the form of pulses of the shape of half sinusoids. Though it is unidirectional it does not have a steady value.”