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High Voltage Circuit trouble

by IEEE1394
Tags: circuit, trouble, voltage
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Dec28-08, 08:29 PM
P: 1
I'm working on building an electrolysis device in hopes of creating a healthy supply of hydrogen.

I tried building a high voltage DC to DC upcoverter based on a tutorial found on instructables. The tutorial made use of the flash circuitry found in disposible kodak cameras. The only problem with this circuit was that it was rated for 3v input otherwise the transistor would burn out. I replaced the transistor with a c2236 transistor I obtained elsewhere. Here is the datasheet for the replacement transistor: With the new transistor, I was able to feed 5v from a computer psu without problem. This produced an output of 1000+ V. The power supply said the 5v lines were good for upto 29 A.

Just when I thought I was in the clear, another problem occurs. When I hook up the circuit to electrodes (stainless steel forks) in a vat of vinegar/water electrolyte, the voltage between the forks read only 4V!

I'm not sure what the problem is so this is where you come in, Physics Forums. My guess is that the electrolyte has too high of a resistance and the circuit is not allowing enough amperage to pass through the electrodes. Please pardon my lack of knowledge as I'm just a high school student working on this project with a friend.

Below is the link to the circuit that was constructed.

And this is the circuit diagram.

Thanks for looking.
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Dec28-08, 08:54 PM
P: 143
Typically, flash circuitry like that in a camera isn't made to sustain high voltage while deliverying a steady current (just a short burst of low current at high voltage) nor are they intended to deliver high or decent levels of steady current. Chances are, the high voltage circuit simply cannot deliver the amount of current that the electrolysis process requires and is simply being loaded down, as expected.
Proton Soup
Dec28-08, 09:28 PM
P: 1,070
um... why high voltage? you trying to get killed? i used to electrolyze water when i was a kid, and i don't remember the voltage needing to be that high at all. i wouldn't go anywhere near water with voltage any higher than about 24VDC myself.

bigger problem may be that unless you've got a decent electrode material, it'll corrode very fast.

Dec29-08, 11:59 AM
P: 1
High Voltage Circuit trouble

I agreed with Proton Soup that high voltage is very dangerous.

Why did you settle on this particular electrolysis design?
Jan1-09, 12:22 AM
P: 303
the current running through the water is loading down your output.
Jan1-09, 02:44 AM
P: 4,512
Electrolysis is a Low Voltage process. It's something like a battery in reverse. The electrochemical reaction requires somewhere less than ~5 volts. The rate of hydrogen production is proportional to the current.

Required is high current, low voltage.

To discover the required voltage, one could reference oxidation/reduction potentials, if one knew the reactions going on. Even with carbon electrodes, you have to add a salt to the water, so things get complicated.

I'm in no way a chemist. I'd use a variable power supply to discover empirically what voltage was required, and get better numbers too.

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