I need some help! Detecting DC voltage circuit diagram

Hi everyone,

Im an electronics newby but I'm very keen to learn.. I have some basic knowledge from school/college but nothing too fancy. It's a start though eh!

Anyway, I have a requirement to detect up to 2.3v p-p DC without draining or effecting the original supply. I.e a passive DC power supply detector I guess!? Im thinking the circuit will need its own power supply and Id also like to display the presence of power with the use of an LED if possible? The most important thing is to keep things low cost and low power consuming.

I'm hoping one of you experts can help me out? Is it even possible??

Thanks in advance.

Matt

If you're trying to detect 2.3VDC, apply that DC voltage to the gate of a MOSFET with a low threshold voltage or to the input of an op amp. Those will tell you if a DC voltage is present.

Thanks for the great advice ). I've taken a look online at rswww.com.. There are a lot of op-amps and mosfets! Could you possibly recommend some for me as a starting point? Perhaps if its not to much trouble post a link for me? Im sorry to be a complete numpty. For now im going to power the circuit with a 9v battery fyi..

Also, Will I be able to get an LED to light on power detection using an op-amp? I think it looks like I can but I just wanted to check?

Thanks a lot

Matt