For an active magnetic field compensator for an electron microscope, needs to build V to I converter

Thread Starter


Joined Aug 31, 2018
Hey Guys,

I have a question concerning a project i am doing for University: I am supposed to help build an active magnetic field compensator for an electron microscope.

For that i need a current driver (I'm not even sure if that's the right word) that can convert a small voltage (tens of mV) from the sensor into a large current (1+ A). It should also be quite fast and accurate between DC and about 1kHz.

I have tried to build a circuit but it's not working so far (i'll try to upload a picture later) and i don't really find a lot of helpful stuff on google neither.

I hope you guys can help me out or maybe tell me what to search for.

Many thanks in advance.



Joined Mar 14, 2008
That likely could be done with an opamp and a transistor configured as a constant current drive.

Does the current need to go in both directions or only one direction through the coil?
Can you use a low-side drive to the field coil?
What is the coil voltage and maximum current?