This circuit was based on Maxim's MAX4374. The circuit senses the current in a 0 to 20 V line and has a timed output signal, with time given by R1 and C1. Power is supplied with 5V.
The circuit shown is from the Texas Instruments optoelectronics manual, applying to low power...
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...
This filter that rejects a frequency range determined by the double-T was found in the August 1993...