Naked Science Forum

On the Lighter Side => Science Experiments => Topic started by: dvijay on 07/08/2009 10:36:56

Title: Want to make 12v dc current to turn into 1v ac
Post by: dvijay on 07/08/2009 10:36:56: I want to turn a 12v dc current from a battery to 1v ac having 300 hertz cycle.The device should withstand 10 ampere current.

Can anybody guide me about this circuit.It should be light weight. [:o]
Title: Want to make 12v dc current to turn into 1v ac
Post by: daveshorts on 11/08/2009 13:12:13: 10 amps on the input or output and does the ac have to be sinusoidal or can it be a square wave?
Title: Want to make 12v dc current to turn into 1v ac
Post by: dvijay on 12/08/2009 04:32:38: Thanks for the interest.
The a/c current may be sine wave or square wave dosent matter(what difference it will be in the cost)and output is max 10amps.For aircraft 400 hertz is used,so it will be ok.
I am not good at electronics.Please explain as if I am a new lerner.
Thanks,and waiting for your reply.
Title: Want to make 12v dc current to turn into 1v ac
Post by: techmind on 15/08/2009 00:01:19: Square wave will be cheaper and easier... but what on earth do you want 10A at one volt for?

Realistically you'd use a DC-DC converter to get you 1V (ish) at DC, then use 4 heavy-duty transistors (probably MOSFET) to give you switched square-wave ac.
If it's going to be lightweight, you'll use the DC-DC converter running at several tens of kilohertz, and it'll use a ferrite-cored transformer internally.

Rectifying the ac in the output of the DC-DC converter (1volt-ish) will be horribly inefficient because you'll be dropping half a volt (ie half your final power) in the diodes. Euurrrghhh! I guess you get special low-drop diodes - they must use them in computer power supplies since modern microprocessors use many amps at around 1V. You could probably learn some relevant tricks from looking at modern computer PSUs.

You won't be able to make efficient use of this 1volt with electronics, so I guess you want to use it for a motor or tungsten bulb or something?
But a bulb wouldn't need AC, and an AC motor powered by a square wave would judder like crazy, sound ghastly, and possibly shake apart its bearings and anything mechanically coupled to it.

If there's some connection to aircraft, why use 300Hz instead of 400Hz? They'll be no cost or complexity difference.

If you are new to electronics then this will be a very ambitious project. You might be able to get a 12V to 1V DC converter "off the shelf" (probably from a Chinese supplier), but I reckon the 300Hz AC bit is non-standard enough that you'll have to roll your own there.
Title: Want to make 12v dc current to turn into 1v ac
Post by: RD on 15/08/2009 20:53:53: Dvijay may be looking for PWM (http://en.wikipedia.org/wiki/Pulse-width_modulation) to control the motor powering a model aircraft propeller, (which can draw a high current).
Title: Want to make 12v dc current to turn into 1v ac
Post by: dvijay on 18/08/2009 11:10:28: Ok,Just I thought 300hz is less than 400hz so it will be easy.Something like that.But 400hz is ok because I am not going to use on any motor or any electronic device.My need is low voltage,high frequency and also the current consumption will be high also.

Conversion from dc to ac as well as greating the high frequency is the problem for me.
Title: Want to make 12v dc current to turn into 1v ac
Post by: dvijay on 18/08/2009 11:14:27: Just I want to try a thing which came to mind.If it works well I will publish it here itself.
Title: Want to make 12v dc current to turn into 1v ac
Post by: FuzzyUK on 25/11/2009 22:41:42: Quote from: dvijay on 18/08/2009 11:14:27
Just I want to try a thing which came to mind.If it works well I will publish it here itself.

What possible device would run off a 1v AC supply and draw 10A ?
Title: Want to make 12v dc current to turn into 1v ac
Post by: Geezer on 26/11/2009 03:18:55: Degausser perhaps? Maybe he's doing a bit of welding. [???]

Anyway, one way to do it is to convert to AC at 300Hz first, then push it through a transformer. The transformer won't need to be all that large, but the secondary winding will need some hefty wire [:)]
Title: Want to make 12v dc current to turn into 1v ac
Post by: FuzzyUK on 26/11/2009 18:29:48: Quote from: Geezer on 26/11/2009 03:18:55
Degausser perhaps? Maybe he's doing a bit of welding. [???]

dvijay is being vague and not specifying what his application is. We don't know whether he really needs a 1v AC 300Hz supply capable of delivering 10A. He also says he is a beginner at electronics so I'm afraid I can't help him given lack of information on his project.
Title: Want to make 12v dc current to turn into 1v ac
Post by: Geezer on 26/11/2009 20:01:26: I remember once being assigned the task of winding a few turns of really heavy wire on to a big torroid to produce a really high current output. I had to beat the wire with a rawhide mallet to form it!

If I remember, the application was manufacturing permanent magnets, so I suppose there must have been a rectifier involved.
Title: Want to make 12v dc current to turn into 1v ac
Post by: dvijay on 13/04/2010 09:38:00: I got the circuit now.It is just a basic inverter circuit.now I have changed my mind to have 12v dc to 12v ac,square wave and around 24a.