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Re: Circuit design help - power supply - Non FIRST
the efficiency problem you are facing is using any type of amplifier.
Amps work by taking a DC power supply output and holding back the part of the voltage that does not match the input. Subtracting the AC output from the DC power input leaves about half the input power dissipated by the amp (the Mosfet driver mostly) - so you are looking at 50% efficiency or less with this approach. The only way you can get around this is to use a squarewave output. This would keep the mosfet driver out of its linear range, so its either full on or full off. In either state its power dissipation is negligible. (this is how a Victor speed controller work).
If you want to approach 90-95% efficiency with a sine wave output you are going to need something like a motor generator set: a motor that drives an AC generator. The speed of the driving motor will determine the frequency of the AC output. The output can then be full-wave rectified.
Then all you need for your application is a DC offset (DC power supply in parallel with the AC rectifier). The diodes in the rectifier will keep the DC bias supply from back-feeding the AC generator.
The biggest risk you face is having something wrong with the DC bias. The O2 and H2 form at the opposite polarity electrodes. If your bias goes negative for any reason you will have a small amount of O2 in your H2 collector. Hydrogen and oxygen mixed together is subject to spontaneous combustion.
The only way you can be sure your electrodes are properly biased is with an oscilloscope.
Last edited by KenWittlief : 23-12-2005 at 11:17.
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