VCCS with coil dual drive?

[Robert Marks]

I am using an LM358 to apply a dual drive to a 2K solenoid at 1-100Hz.
It runs off 4 "AAA" cells.

This is a device to calibrate magnetometers, so maximum field
intensity and waveform fidelity is desirable.

As there is no load reference to earth in this configuration, what is
the simplest way to sense current in the coil and provide feedback to
each of the op amps in the dual package?

Thanks very much for any advice.

Robert

 

[Mac]

I am using an LM358 to apply a dual drive to a 2K solenoid at 1-100Hz.
It runs off 4 "AAA" cells.

This is a device to calibrate magnetometers, so maximum field
intensity and waveform fidelity is desirable.

As there is no load reference to earth in this configuration, what is
the simplest way to sense current in the coil and provide feedback to
each of the op amps in the dual package?

Thanks very much for any advice.

Robert

If you want a VCCS, maybe you should go read the recent thread in
sci.electronics design (this group) with this subject: "Bipolar current
source for muscle stimulations"

You might also appreciate the recent episode of the Bob Pease Show which
dealt with current sources:

http://www.national.com/nationaltv/

You want episode 6.

Whatever solution you use, you will probably end up needing very closely
matched resistors.

--Mac