Tuesday, September 01, 2009

Difference Amplifier Forms Heart of Precision Current Source

Precision current sources are used to provide excitation for RTDs in process-control systems; to measure unknown elements in digital multimeters; and to drive 4 mA to 20 mA current loops, which are widely used to transmit information over long distances. This article shows how a difference amplifier can be used to implement a precision current source.


At 3:33 AM, Anonymous BMDMAN said...

Great article, very well laid out. I shall be filing this away in my library. I'm sure this will find its way into one of my designs.


At 6:17 AM, Anonymous Anonymous said...

Thanks for your article!

I am going to use this schematic to drive a HGT-3030 Hall sensor which requires a bit of more stabilized current with respect to the 4 / 20 mA.

Here's some specs:
Input/Output resistance ~ 2 ohm
Nominal control current = 100mA
Maximum continuous current = 300mA

What kind of modifications do you suggest to the basic circuit to drive high currents?

Thank you


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