App note: Precision current-transmitter/source-sink calibrator with wide range

Posted on Saturday, June 23rd, 2012 in app notes by Ian

rsdio writes:  In conjunction with the recent discussion of how difficult it is to control current draw (in a USB Device), here is an example of a circuit that sinks (draws) a precise current, rather than creating a specific voltage.

Precision Current-Transmitter/Source-Sink Calibrator Has Wide Compliance Range

Based on a precision op amp (MAX4236), this loop-powered, high-compliance, precision current sink (or source) can be modified for use as a 4–20mA sink transmitter.

A similar version of this article appeared in the March 24, 2009 issue of ED magazine.

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