AC Voltage Tripler

Can someone please explain this circuit to me.

I don't get it. Should the load not be over c1 c3? (the diodes need reversing as well)

My understanding seems to end at a voltage doubler.

I'm going to try to explain how it works....

The ac signal passes through C1 and D1 clamps the most negative part of the signal to ground, so the whole of the ac signal is above ground.(+ve)

Now this signal goes through C3 which has D3 stopping the most negative part of the waveform going below the positive peak of the input signal as rectified and filtered by D2 & C2, this means the output voltage is now the ac peak to peak voltage plus itself.

As I can't see the original circuit I've had to guess at the component references but the way it works is straightforward.

Hope that helps!! - John.

I think the problem is the diode in your load which is basically a voltage clamp. Before you add the load you would have 12 X 3. = 36, but when you add the load you would have 12 X 3 / 2 = 18v

I am going to go with asking the really obvious question - "what oscillator circuit are you using to power the transformer"?

If you are just connecting a 12V DC battery up to the transformer you are not going to get anything out. You need an alternating voltage (AC) created by a transistor flip-flop circuit, 555 timer chip or one of the many other charge-pump oscillator chips designed especially for this application (many, such as the MAX1044 switched-capacitor voltage converter do not even need a transformer).

Try goggling "MAX1044" or "Voltage tripler". Other sites on the web with voltage tripler circuits include

http://www.geofex.com/

There are plenty more.

Since you are already using a transformer, why don't you just use one with three times as many turns on the secondary, and get rid of all the caps etc.?

The sad reality of a charge pump circuit, which this is, (you might think of it as successive charge pumps) is that you can't usually get a lot of power out of it due to limits in the ESR of the capacitors and the fact that you are chaining successive charge pumps. Think of a bucket brigade except that as you go along the buckets get smaller fast.

It is far more efficient to use a step up transformer.

add you score for your answer.

indeed, it depends on frequency and load. in one words. energy.

You should get more than 2V. Check your circuit. You might have a burned diode, bad connection, or reversed cap.

Good luck