1)What is the advantage of a Voltage Doubler over a half Wave Rectifier?
For the same size and rating of the Transformer, Voltage Doublers produce two times the voltage as that produced by half wave rectification.
2)How is the Voltage Doubling achieved?
As both the capacitors are in series with each other and the load, the opposite voltages generated in both of them will add up and get discharged to the load. Thus a doubling effect will be produced, delivering a voltage which is twice the input. However, it is to be noted that the system will work only if the load is very small.
3)Are the two capcitors used in the Voltage Doubler identically rated?
C1 is often greater than C2 because, with the charge being conserved, C1 gets charged to a voltage of V whereas C2 gets charged to 2V.
4)What is the range of load currents that can be handled by Doubler?
As pointed out earlier, the doubling effect is produced only if the load is small. Load currents are typically in the range of 1-100µA.
5)On what parameters does the Voltage Ripple depend?
Ripple=I/2f[1/C2+2/C1];
Ripple increases with increase in current and decreases with increase in frequency.
Higher values of C1 & C2 can also reduce the ripple. However, pratical constraints limit the size of the capacitors due to which large values, especially at high voltages can not be easily achieved.