I need to increase the voltage of a signal (little current here as the voltage is just being recorded) from around 70mv to around 1 or 2 volts. I see there is a ton of op-amps at digikey - but I have no idea which one to use. Of course it must amplify DC - any suggestions would be helpful. If it helps, my application follows.
I'm monitoring all three phases of an electrical service (maybe even the neutral - so that would be four). I want to monitor current in the range of 5a - 100a. I'm using current clamps that I purchased on eBay. I want to read it with a small device (DataQ DI-149) that connects to my computer so that I have a constant log - but the DataQ reads only from 0 to 10 volts. I would change the signal from the clamp to DC (via bridge) so that it is easier to read with my Dataq voltage reader. The problem is that the current clamp only outputs a maximum of 10mv per amp and that will barely register on a device designed for 0-10 volts. If I'm reading say 8 amps with the clamp then the clamp output is only 80mv - less than a tenth of a volt. I would also like to vary the gain so that I can more accurately monitor higher or lower current (so the display in my monitoring graph doesn't top-out or bottom out.
I know there are very popular versions of certain products (ie 555 timer) that people have used for years - maybe that's what I'm looking for... but of course the op-amp standard of the same idea? Some product or circuit where I can get started...
I'm monitoring all three phases of an electrical service (maybe even the neutral - so that would be four). I want to monitor current in the range of 5a - 100a. I'm using current clamps that I purchased on eBay. I want to read it with a small device (DataQ DI-149) that connects to my computer so that I have a constant log - but the DataQ reads only from 0 to 10 volts. I would change the signal from the clamp to DC (via bridge) so that it is easier to read with my Dataq voltage reader. The problem is that the current clamp only outputs a maximum of 10mv per amp and that will barely register on a device designed for 0-10 volts. If I'm reading say 8 amps with the clamp then the clamp output is only 80mv - less than a tenth of a volt. I would also like to vary the gain so that I can more accurately monitor higher or lower current (so the display in my monitoring graph doesn't top-out or bottom out.
I know there are very popular versions of certain products (ie 555 timer) that people have used for years - maybe that's what I'm looking for... but of course the op-amp standard of the same idea? Some product or circuit where I can get started...