Hi, I'm trying to build what a biologist would call a "stimulus isolator". That is, I have a voltage follower connected to a system that I want to zap with 0-100V, so that the voltage follower doesn't see the voltage (much). I have an A/D board that can put out 0 to 5 Volts. I want this converted to 0-100 V. The thing that vaguely complicates matter, is I that the resistance of the output (the input impedance of the system this is driving) will be variable. I keep thinking op-amps, but then I get confused about how the earth would be connected so that the output was isolated. Previously I've used a photovoltaic relay (PVA1354) to do similar things, but now instead of gating the voltage, I want to control it. Does anyone have any thoughts. I apologize if this is monstrously retarded, I'm just a humble biologist.