My electronic component availability is stuck in the 80's. Surely there must be some cheap few pin ic to do the following.
I want to measure the difference between two points, like between a resistor on the board of an instrument. A multimeter does the job. But I want instead to measure the voltage and send it to a pc voltage logger. The problem is that the resistor could be at 100s of volts above earth and the pc is earthed and so is the voltage logger. How do I add an isolator of some kind? This must be a very common problem.
Cheers