I'm thinking of using an op-amp in a measurement circuitry. The sample will be in series with the op-amp and will be subjected to at most 50V AC (amplitude) at a maximum of 324kHz (although more likely at 60Vpp and 324kHz).
I'm not sure what to look for in my op-amp or if the fact that I'm applying such high voltages and frequencies to my sample will be a factor in choosing an op-amp.
Hope someone can point me in the right direction towards choosing the right op-amp! Thanks.
EDIT: I forgot to mention that it'll be used as current-to-voltage converter.
EDIT: Here is the circuitry that I will be building. The sample here refers to my dielectric sample.
Best Answer
You only need to be concerned about the voltage that the op-amp will actually see, both when negative feedback is intact, and when negative feedback is broken. If you use a "typical" transimpedance amplifier (i.e., current to voltage converter), shown below, for example, so long as you choose the resistor such that the output voltage never exceeds the capabilities of the op-amp, then both of the input terminals will be at zero volts (the inverting input as a "virtual ground"), and everything is OK. If your op amp needs to go above its output capabilities to keep feedback going, all bets are off about what the voltage can be at the inverting terminal, and you can damage your op amp. There are a variety of methods available to "clamp" your input to the range that won't damage your op amp should feedback failure occur, like zener diodes. Your output won't be indicative of the current input, but it won't break.
Alternatively, you might be able to find an op amp that works across the voltage you may see during open loop behavior.
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