3.1 Design an unregulated power supply that uses two silicon diodes, which will deliver
an average current of 200mA to a dc motor having a resistance of 60 ohms. The
applied voltage is 220V(RMS) at 50 Hz. NOTE:- Show all calculations and draw the
circuit diagram. Give the appropriate minimum power ratings of the diodes and the
motor used in the circuit. TAKE the voltdrop across any diode to be 0,7V. (16)
3.2 Calculate the RMS voltage and current rating of a fuse that is placed in the primary
winding of the transformer, that would prevent the secondary circuit from drawing
more than an average current of 250mA. (4)
3.3 An oscilloscope has the following settings:timebase = 2mS/div
amplitude = 5V/div
With reference to question 3.2, draw the voltage waveforms, on the graticules
provided on figure 1 (to be handed in with your answer script), that would be
measured by an oscilloscope when connected across:
3.3.1 the secondary winding of the transformer.
3.3.2 the dc motor.
3.3.3 one of the diodes
3.1 Design an unregulated power supply that uses two silicon diodes, which will deliver
an average current of 200mA to a dc motor having a resistance of 60 ohms. The
applied voltage is 220V(RMS) at 50 Hz. NOTE:- Show all calculations and draw the
circuit diagram. Give the appropriate minimum power ratings of the diodes and the
motor used in the circuit. TAKE the voltdrop across any diode to be 0,7V. (16)
3.2 Calculate the RMS voltage and current rating of a fuse that is placed in the primary
winding of the transformer, that would prevent the secondary circuit from drawing
more than an average current of 250mA. (4)
3.3 An oscilloscope has the following settings:timebase = 2mS/div
amplitude = 5V/div
With reference to question 3.2, draw the voltage waveforms, on the graticules
provided on figure 1 (to be handed in with your answer script), that would be
measured by an oscilloscope when connected across:
3.3.1 the secondary winding of the transformer.
3.3.2 the dc motor.
3.3.3 one of the diodes
