[sdiy] OT: High voltage diff amp

[Paul Perry]

I believe this can be done with a LM3900.
I seem to remember somethng about this
from reading the application notes years ago.
(not that the LM3900 is an ordinary op amp, of course).

paul perry Melbourne Australia
----- Original Message ----- 

> I have a signal (few volts) riding on top of high common mode voltage (few
> hundreds of volts). I need to isolate only the differential signal. Any
> advice on how I should approach this?
> It's relatively low frequency (basically pulsed DC). Super-low cost is not
> a requirement but I'd prefer to keep the unit affordable.