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11.8:

Half wave rectifier

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Electrical Engineering
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Half wave rectifier

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A diode rectifier circuit converts AC voltage into a unidirectional DC voltage using either half-wave or full-wave configurations. Consider a half-wave rectifier circuit consisting of a diode, resistor, and input sinusoidal signal in series combination. During the positive half-cycles of the input signal, when the voltage exceeds or equals the diode's voltage drop, it becomes forward-biased, allowing current to flow. The output voltage is then determined by subtracting the diode's voltage drop from the input voltage. Conversely, during the negative half-cycle, the input voltage is lower than the diode's voltage drop, and the diode remains non-conductive, resulting in a zero output voltage. Despite the input voltage changing polarity with an average value of zero, the output remains unidirectional with a consistent average value due to rectification. Peak inverse voltage represents the maximum reverse voltage a diode can withstand without damage. In a half-wave rectifier, this occurs during negative half-cycles when the input voltage reaches its peak in the negative direction. So, the peak inverse voltage equals the input voltage peak but with reversed polarity.

11.8:

Half wave rectifier

A half-wave rectifier is a fundamental circuit in electronics, designed to convert alternating current (AC) voltage into a unidirectional voltage. It utilizes the simplest form of diode rectification, where the circuit comprises a single diode in series with a load resistor and an AC power source.

Figure 1

The operation of a half-wave rectifier is based on the principle that diodes permit current flow in only one direction. During the positive half-cycles of the AC input, the diode is forward-biased as the input voltage exceeds the diode's threshold. Consequently, current flows through the circuit, and an output voltage develops across the load resistor. This output voltage is the input voltage minus the forward voltage drop of the diode.

On the flip side, during the negative half-cycles, the diode is reverse-biased. The input voltage doesn't suffice to overcome the diode's inherent potential barrier, rendering the diode non-conductive. Hence, there's no current flow, and the output voltage drops to zero. This rectification results in a pulsating direct current (DC) that flows only during the positive half-cycles of the input AC signal.

A crucial parameter for diodes in rectifier circuits is the peak inverse voltage (PIV). This is the maximum voltage the diode can withstand in reverse-biased conditions without undergoing breakdown. In a half-wave rectifier, the PIV is essentially the peak value of the input AC voltage but with an opposite polarity. It's vital that the chosen diode can handle the expected PIV to prevent damage and ensure the circuit's longevity.

Equation 1