Govt. Exams
Entrance Exams
For a boost converter, Vo/Vin = 1/(1-D). With D=0.5, Vo = 12/(1-0.5) = 24V
The motor inductance tends to maintain current flow. The freewheeling diode provides a path for this current when the main switch is off, preventing voltage spikes.
Sinusoidal PWM produces a voltage waveform containing the fundamental frequency plus high-frequency harmonics that can be filtered out.
Turn-off time (tq) determines the minimum period required between successive gate pulses, thus limiting the maximum operating frequency of thyristors.
A buck converter steps down the input voltage. The output voltage Vo = D×Vin where D is the duty cycle (0 < D < 1), making output always less than input.
Threshold voltage (Vth) is the gate-source voltage required to create an inversion layer and allow current flow in MOSFET.
PIV rating defines the maximum reverse voltage a diode can withstand without breaking down. Exceeding this causes reverse breakdown and device failure.
An inverter converts DC power to AC power. Rectifiers do the opposite (AC to DC). Choppers convert DC to DC.
Silicon diodes have a typical forward voltage drop of 0.6-0.7 V at room temperature. Germanium diodes have ~0.3 V.
Both diodes and thyristors are unidirectional devices that conduct current in only one direction. MOSFETs are bidirectional.
