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Polarity Switch

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Hero999
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Electronics God

Posts: 2471

 « Reply #14 on: December 05, 2009, 05:37:22 PM »

Quote
Any Response?
Be patient, I don't sit at the computer 24/7!

If it's one of those rediculas run your car from water schemes then you've probably been told that it won't work many times before on other forums. In case you've not been told before: electrolysis can't be used for perpetual motion because, burning hydrogen releases less energy than what is required to split up water into hydrogen and oxygen.

If you just want to produce hydrogen gas then electrolysis is the easiest way for a hobbyist to do it.

Some people talk a load of rubbish about how liquid water supposedly has a resonant frequency which can be easily excited to increase the efficiency of hydrogen extraction. The truth is that liquid water has no strong resonance, any resonance is strongly damped by the hydrogen bonds holding each molecule to its neighbour. Gaseous water does exhibit a strong resonance but the lowest mode is way up in the microwave band at 22GHz which is almost ten times the frequency used in a microwave oven.

http://www.zyra.org.uk/microw.htm

DC is best for electrolysis not AC. The ions in the liquid move very slowly so changing the polarity at a high frequency would just cause the process to reverse itself as quickly as it's happening with no electrolysis actually occurring. If you used a duty cycle of 50% the water would just heat up due to Ohmic heating. Altering the duty cycles results in electrolysis occurring equivalent to the average current flow. For example a duty cycle of 25% with a current of 30A will perform electrolysis at the same rate as a current of 15A, if the duty cycle is increased to 75% the electrolysis will still be equivalent to 15A, it's just the average current will be in the reverse direction so the oxygen and hydrogen bubbles will exchange electrodes.

I think using a constant current source is your best bet. Pure water is also a very poor conductor because it doesn't have many mobile ions. Tap water isn't pure but it might not be ionic enough to work really well; to improve the efficiency of electrolysis you need to add a salt to increase the conductivity. You could use common salt (sodium chloride) but it would produce toxic chlorine gas and leave a nasty caustic solution behind.
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Please ask on the open forum if you have a question: if I know the answer, I'll be happy to help.

cbr549
Newbie

Posts: 12

 « Reply #15 on: December 05, 2009, 07:16:51 PM »

Neither do I but
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Hero999
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Electronics God

Posts: 2471

 « Reply #16 on: December 05, 2009, 08:03:05 PM »

Neither do I but
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I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question: if I know the answer, I'll be happy to help.

cbr549
Newbie

Posts: 12

 « Reply #17 on: December 06, 2009, 04:23:06 PM »

I do apologize! My comments were evidently taken the wrong way!
I should have realized that someone so obviously more knowledgeable than I would have already tried to do what I
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Hero999
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Electronics God

Posts: 2471

 « Reply #18 on: December 06, 2009, 06:11:54 PM »

I'm not going to go trough all your flamebait, I'll give you one last chance.

I've only made a load of assumptions in the absence of any concrete information.

I still don't know what your end goal is. Why haven't you told us? Is it a secret?

You'll get more help if you had just provided this information from the very beginning.

Quote

I might have seemed to be arrogant but I can assure you it isn't the case, it's something you've assumed.I think you took my comments out of context, so what I'm probably more knowledgeable when it comes to electronics? I didn't mean to imply that I'm more knowledgeable than you full stop.  You could be twice as intelligent as me for all I know.  My point was that if you're asking someone for advice with something that you're having difficulty with then you should provide them with as much information as you can and not go on the defensive when they question your existing idea.

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Do you want to do this or not?

For the final time: what is your end goal?

I am asking this question for your own good because from what you've said, it doesn't sound like you're going the correct way of doing something.

How do I know this?

I don't really know for sure but I have this feeling because as far as I'm aware there is no real world application for a 12V 30A 0-15MHz AC PWM power supply.
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I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question: if I know the answer, I'll be happy to help.

audioguru
Electronics God

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Posts: 14190

I'm a theory expert! \$crooge and I are thrifty.

 « Reply #19 on: December 06, 2009, 08:07:11 PM »

All the idiots who are trying to make HHO for their cars should be banned from electyronic chat forums.
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cbr549
Newbie

Posts: 12

 « Reply #20 on: December 07, 2009, 11:29:10 AM »

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cbr549
Newbie

Posts: 12

 « Reply #21 on: December 07, 2009, 11:33:36 AM »

Quote

For the final time: what is your end goal?

I am asking this question for your own good because from what you've said, it doesn't sound like you're going the correct way of doing something.

How do I know this?

I don't really know for sure but I have this feeling because as far as I'm aware there is no real world application for a 12V 30A 0-15MHz AC PWM power supply.

Now back to what
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Hero999
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Electronics God

Posts: 2471

 « Reply #22 on: December 07, 2009, 04:22:25 PM »

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I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question: if I know the answer, I'll be happy to help.

cbr549
Newbie

Posts: 12

 « Reply #23 on: December 07, 2009, 04:41:41 PM »

Thanks anyway, I found one one on-line and cheaper too!
Anyway, I
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Hero999
Global Moderator
Electronics God

Posts: 2471

 « Reply #24 on: December 08, 2009, 06:41:05 AM »

Thanks anyway, I found one one on-line and cheaper too!
How do you know it's cheaper than what I was going to suggest? I just gave you a worst case scenario of what it might cost.

Care to redeem yourself by posting a link to it?

Quote
Anyway, I
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I also post at:
http://www.silicontronics.com

I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question: if I know the answer, I'll be happy to help.

Riccardo
Jr. Member

Posts: 66

 « Reply #25 on: December 09, 2009, 06:08:56 PM »

Wow, Is it hot in here

I don't want to get into the argument so I'll just answer the original questions.

I was looking to use a VNH3SP30-E as is it a H-Bridge device that makes things easier but it was not powerful enough for me. I'll now be making my own h-bride. Its a lot more effort, but I'll gain good experience and it will do what I want.

Hero999 was very helpful to me in working out what to do.

I had some custom software from these guys, but they also do electronics.
http://www.rmcybernetics.com/shop/custom-electronics-programming.htm

PWM adjustable from low frequency to MHz wont be cheap though. Not sure it is even possible in any realistic way. 0Hz to 100kHz might be more reasonable.
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