This is a simple voltage doubler circuit which has the output voltage is 2xVin
The above circuit is cascade type voltage doubler circuit.
Note : both type of the above voltage doubler circuit must have rated voltage of capacitor and diode greater than 2 times of Vin.
This circuit will give the output voltage 3 times of input voltage.
The rated voltage of all capacitors and diodes must be greater than 2 times of Vin.
The above circuit is a voltage quadrupler circuit which have the output voltage is 4 times of Vin.The rated voltage for all capacitor and diode must be ggreater than 2 times of Vin.