[SOLVED] Op Amp for low DC amplification

[PixieBow]

I have a small DC voltage of about 10mV. I want to use an Op Amp and amplify the voltage to about 10V. Is this possible? Do we get amplifiers with gains of 1000 for, say, $5? And will I be able to utilise this voltage to run lights bulbs?? I'm guessing current would drop by a large amount? :-?
Another question, might sound silly- can I derive more voltage by amplification than what I'm providing to the OpAmp supply? I mean, if the required supply to the OpAmp is ±15v, can I amplify my 10mV to more than 30V??

 

[alexan_e]

You could use an instrumentation amplifier like AD620 www.analog.com/static/imported-files/data_sheets/AD620.pdf

The output current is limited so it can not drive lights bulbs directly but depending on what you want to do you can use transistors, relay etc.

if the required supply to the OpAmp is ±15v, can I amplify my 10mV to more than 30V??

No that is is not possible, depending on the device you can reach the supply lives voltage at best.

 

[PixieBow]

Great, thanks for the instrumentation amp link, alexan_e.

Ok, the initial 10mV that I'm getting is waste power from a device, which I want to use productively somewhere, to reduce my overall power consumption. I was thinking of using it either to drive bulbs, or to charge a mobile phone or something similar. But from your explanation, I'm gathering that I would in fact be wasting more power than I'd recover. Am I correct in my understanding? Could you suggest a model where I could utilise this power?

Cheers

 

[alexan_e]

If the point of the amplification was to utilize the 10mV source then you will waste even more power.
Maybe I misunderstood, I thought that you had a 10mv source (like from a shunt resistor) that you wanted to amplify in levels that could be measured but it was obviously not that.

Any circuit you add to amplify the 10mV you will waste more and more power, none of them will have 100% efficiency.

 

[PixieBow]

Oh :| Thanks!