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Converts an AC to a greater DC. During the negative half of the sinus wave, the capacitors are charged almost like in parallel and during the positive halve wave, they add up their voltage as if connected in series.
You can use it to generate positiv or negative voltages as seen in this example. Using a 9VAC "wall wart" you can have 5V, +15V and -15V for mixed analogue and digital circuits.
This circuit used to be used in early TV sets to generate the HV for the picture tube. Any load reduces the performance of the circuit dramatically but this is OK for the tiny anode current of a black and white picture tube.
In those "ancient" TV sets, a lot of stages were used to generate between 10 and 18kV. In this simple example, only 2 stages are used. You should be able to see thr pattern to add as many stages as you like. Also you can crank up the input voltage, a TV set had driven their cascades with up to 300V AC!
The beauty of this concept is that all parts are driven with equal or less voltage than the input voltage. When the first TV sets were made, silicon diodes were very weak and couln't resit more than a few hundred volts in reverse. So this was the method of choice to generate HV with low voltage parts.
I used 9V in this example since the Commodore 64 has a 9VAC output on its user port I often used to generate the +/- 15V for various analogue circuits using this circuit and Z-diodes.
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