With a half-wave rectified voltage across a load resistor, load current exists for what part of a cycle?
Group of answer choices
A 180 degrees
B 90 degrees
C 0 degrees
D 360 degrees
The correct answer and explanation is:
The correct answer is A 180 degrees.
In a half-wave rectifier, the input AC signal is passed through a diode, which only allows current to flow during one half of the AC cycle. This results in current flowing through the load resistor for only a portion of the input waveform.
During a full AC cycle, the input voltage alternates between positive and negative values. In a half-wave rectification process, the diode conducts only during the positive half-cycle of the input voltage. When the AC voltage is positive, the diode becomes forward-biased and allows current to flow through the load resistor. In contrast, during the negative half-cycle of the AC input, the diode becomes reverse-biased, and no current flows through the load resistor.
The current thus exists only during the positive half of the AC cycle, which corresponds to a 180-degree portion of the waveform. The negative half-cycle is blocked by the diode, and no current flows during that time. This characteristic results in a pulsating DC output from the half-wave rectifier, with the load current only being present for half of the AC input cycle.
This property is why half-wave rectifiers are less efficient than full-wave rectifiers, as they only use half of the AC waveform to produce output, leading to more ripple and lower average DC voltage across the load.