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An RC circuit (see figure) is driven by an a.c. source generating a square wave. The output waveform seen on a CRO would look closest to
Asked in JEE Main 16th March 1st Shift 2021 · Behaviour of R, L and C separately
- (1) sharp triangular spikes at each edge
- (2) exponential charge-and-discharge (rounded) curves
- (3) the input square wave, unchanged
- (4) linear ramps (a sawtooth)
Answer: (2) exponential charge-and-discharge (rounded) curves
Step-by-step solution
With a square-wave input the capacitor charges toward the high level and discharges toward the low level each half cycle.
Charging/discharging follow 1-e^-t/RC and e^-t/RC, giving rounded exponential curves.
Why the other options are wrong
- (1) Spikes come from the differentiated output across R, not the capacitor output.
- (3) An RC circuit reshapes the square wave; it does not pass unchanged.
- (4) The charging of a capacitor is exponential, not linear.
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