Voltage doubler

[Baard]

Hello
I have a pair of 1000VA 2x18volt trafos. Is it possible to increase the output via a "voltage-doubler", and if so how can I make one?

Best regards

[Evan Shultz]

check this website http://www.qsl.net/xq2fod/Electron/PS40/PS40.html under the 110V modifications section. it's really just a pair of diodes. good luck

[cunningham]

Yes a voltage doubler circuit will work, the only drawback is you will get 60Hz rectified instead of 120Hz thus leading to more ripple. If you have a large enough capacitor bank, it should work better. Kind of depends on the power vs time consumption of your circuit.

[Stocker]

Hang on a second! I was just looking at my notes about a 120Hz output voltage doubler... let me see if I can find the website. Later tonight if nobody beats me to it...

[Stocker]

Here it is!

I haven't thought about this enough (yet) to get what he is saying about leaving the negaive ground floating or BOOM; but I am about to build a pretty hefty current, low voltage supply and any commentary that will help me avoid the BOOM would be greatly appreciated.

Anyhow, If this can be made to work, it looks like a far superior approach to the standard 2-diode doubler

[Greg Erskine]

Hi Baard,

I just checked my text book "Understanding DC Power Supplies" by Barry Davis and here is a quote:

"These circuits can double, triple, or quadruple the input voltage is desired, but they are only able to supply a small amount of current."

This is referring to simple diode/capacitor circuit so I'm not sure if they are suitable for audio amplifiers.

WARNING: I have no experience with multipliers and am only quoting a text.

[savenger]

Hi, Baard.

Where do you need it for???

Those doublers are no good in power amps, my opinion. You can allways apply those 2 trafos series, getting 2x36v 2000VA.

Edit:
And if that's not enough you can allways make two amps and bridge them and get even more power.

[Stocker]

Guys, if you follow that link the example it gives is 2800V 1A out... And from the layout, I can't see why it wouldn't support a low voltage high current output as well.

Series secondaries would be my first choice (didn't notice that they were 2x each) BUT what if he wants more than the voltage he'll get out of that...

[sam9]

I think of them as a "make-do" solution for audio diy so that you can utilize an existing transformer. A few months ago, however, I found a web site that discussed a more practicle application. Practical in the sense that finding an equivalent tranformer was dubious -- generating very, I mean VERY, high voltage for a VanDeGraf apparatus.

[savenger]

Originally posted by Stocker
BUT what if he wants more than the voltage he'll get out of that...

Then i suggest to sell those trafos and buy new ones with appropriate voltages, but like i edited, bridging 2 amp gives guite a lots of power, but who knows, maybe he want's to make a "ozonator" instead of power amp...

Edit: Depending on trafo you can allways wind more secondary wire, not pretty, but works.