current gain

[schmiddy]

the Elvis labview board outputs a max current of 500mA and I have something that needs power of 5Vdc @ 5A, How would I be able to achieve this current gain? transistors?

Thanks for all the help! 

[schmiddy]

bump

[smercurio_fc]

Confucius say: Patience is power; with time and patience the mulberry leaf becomes silk.

You could use transistors, though that would mean designing your own amplifier. Up to that? If not, you could just buy a programmable power supply, which is probably the safest route to take. 

[schmiddy]

thanks for the reply, I may have access to a programmable power supply but if not it would be costly. I am about to break out my old microelectric circuits textbook. when you say designing your own amplifier do you mean as in the resistor values connected to the transistor or what exactly?

[smercurio_fc]

Ummm.. yes, basically, but....  I don't want to be blunt, but perhaps if you don't know what I mean, and if you are going to "break out my old microelectric circuits textbook" then perhaps this is not something you should be tackling on your own. Textbooks are not good sources for practical circuits. They teach theory, not practicality. You can easily find practical current amplifier circuits on electronics websites if you really want to roll your own.

All of that said, a real note of warning: with 5A you're dealing with a current level that requires care as you can easily fry something, not the least of which would be you. 

[schmiddy]

Thanks for the reply, I understand where you are coming from. What do you think about using http://www.freepatentsonline.com/4804927.html ? or would I be better off going in the direction of opamps?

I will look around for current amplifier circuits, where do you reccommend?

Message Edited by schmiddy on 11-16-2008 06:48 AM

[schmiddy]

how about something along these lines?
http://freecircuitdiagram.com/2008/09/15/current-amplifier-using-ca3140-op-amp/

Message Edited by schmiddy on 11-16-2008 08:06 AM

[smercurio_fc]

I did not look at the circuit at freepatentsonline. That site requires registration, and I'm not going to do that. The second circuit will not work. It is clearly not designed to source 5 Amps.

Look, I know you want to try this yourself and I commend you on your drive, but as a former electrical engineering designer let me give you a word of advice: find someone who knows what they're doing and have them do it for you since you're not willing, or not capable to simply buy an off-the-shelf item. I won't be held responsible for enabling you into damaging your Elvis board because you didn't know what you were doing, or worse, causing physical harm to yourself.