Single phase uncontrolled half wave rectifier with capacitive Load - Circuit Diagram & Wave forms
Single phase uncontrolled half wave rectifier with capacitive Load -Circuit Diagram & Wave forms:
- The problem of poor form factor (ripple factor) of the output voltage can be solved to some extent by connecting a capacitor across the load resistance. If the capacitor was initially discharged the diode “D” is forward biased when the switch S is turned on at ωt = 0.
- The output voltage follows the input voltage. The diode D carries both the capacitor charging current and the load current.
- At ωt = β the sum of these two currents becomes zero and tends to grow in the negative direction. At this point the diode becomes reverse biased and disconnects the load (along with the capacitor) from the supply. The capacitor then discharges with the load current. Diode D does not become forward biased till the input supply voltage becomes equal to the capacitor voltage in the next cycle at ωt = (2π φ).
- We have,
- A very large capacitor helps to improve the ripple factor of the output voltage of this rectifier. However the peak current through the diode increases proportionately.
- The peak reverse voltage appearing across D is given by:
This is also known as the peak inverse voltage rating (PIV) of the diode.