Question 395: AC fundamentals

Question

In a full wave rectifier circuit without filter, the output current is

Accepted Answer

The correct answer to this question is Option D: unidirectional but not steady current.
In a full-wave rectifier circuit, the objective is to convert alternating current (AC) into direct current (DC). The fundamental characteristic of a full-wave rectifier is that it inverts the negative half-cycles of the AC input voltage so that on the output side, the current flows in only one direction for both half-cycles. This makes the output current unidirectional. However, without a filter to smooth out the ripples, the output current is not a constant direct current but a pulsating direct current that still retains the frequency of the original AC signal.
The output current of a full-wave rectifier without a filter can be represented as an absolute value of a sinusoidal wave, meaning it maintains the sinusoidal shape but with all the values above the zero line since the negative values are inverted. This waveform is not constant or steady; instead, it rises and falls with the frequency of the AC input, typically at twice the frequency in the case of a full-wave rectifier because it rectifies both halves of the input sine wave.
So, to summarize:
Option A (an eddy current) is incorrect since eddy currents are localized currents induced in conductors when they are exposed to changing magnetic fields, which is not the output of a rectifier circuit.
Option B (a constant direct current) is incorrect because without a filter (such as a capacitor or an inductor), the output is not constant but pulsating with ripples.
Option C (a sinusoidal current) is incorrect because the resulting current is not sinusoidal; it's the absolute value of a sinusoidal wave, representing both halves of the wave above zero volts.
Option D (unidirectional but not steady current) is correct as the output is indeed unidirectional due to the inversion of the negative half-cycles, but not steady due to the absence of a filter to smooth out the ripples.

Answer

an eddy current

Answer

a constant direct current

Answer

a sinusoidal current

Answer

unidirectional but not steady current

AC fundamentals

In a full wave rectifier circuit without filter, the output current is

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