Choose the incorrect statement with respect to the use of FD in half-w...
PIV is unaffected with the use of FD (freewheeling diodes).
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Choose the incorrect statement with respect to the use of FD in half-w...
Incorrect Statement: Reduces the reverse voltage (PIV) faced by the SCR
Explanation:
To understand why option D is incorrect, let's first understand the concept of forward voltage drop (FD) in half-wave circuits and its impact on various parameters.
1. Forward Voltage Drop (FD):
In a half-wave rectifier circuit, a diode is used to convert alternating current (AC) into direct current (DC). The diode has a forward voltage drop (FD) associated with it, which is the voltage across the diode when it is forward-biased and conducting current. This forward voltage drop depends on the type of diode used.
2. Impact on Parameters:
a) Input Power Factor (PF):
The forward voltage drop (FD) in a diode causes a phase shift between the input voltage and current. This phase shift leads to a lower input power factor. However, the FD does not improve the power factor; it actually degrades it. Therefore, option A is incorrect.
b) Load Current Waveform:
The FD in a diode causes a voltage drop across it, resulting in a non-linear load current waveform. This waveform is characterized by a short conduction time during the positive half-cycle of the input voltage. As a result, the load current waveform is not improved but rather distorted. Therefore, option B is incorrect.
c) Preventing Load Voltage from Becoming Negative:
During the negative half-cycle of the input voltage, the diode is reverse-biased and does not conduct current. This prevents the load voltage from becoming negative and ensures that only the positive half-cycle of the input voltage is rectified. Therefore, option C is correct.
d) Reverse Voltage (PIV) Faced by the SCR:
The reverse voltage (Peak Inverse Voltage or PIV) faced by the silicon-controlled rectifier (SCR) is determined by the peak voltage of the input waveform. The FD in the diode does not affect the reverse voltage faced by the SCR. Therefore, option D is incorrect.
Conclusion:
The correct statement with respect to the use of FD in half-wave circuits is that it prevents the load voltage from becoming negative. The other statements provided in the options are either incorrect or unrelated to the FD in half-wave circuits.
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