The current supervision circuit of photocoupler

Published:2011/5/26 22:25:00 Author:Borg | Keyword: supervision circuit, photocoupler | From:SeekIC

This is a current supervision circuit of photocoupler. In the tested current wires, we put in a resistance of Rs to the test, when the current reaches the regulated value, the voltage on Rs is dropping and the diode in the photocoupler is passable, so the transistor is on, then we cut it offby keeping the grounded potential of VT1 under 0.4V, so the LED is off. When the tested current is dropping, the currents in the diode and transistor of the photocouplerare dropping, so the potential of VT1 rises and it is passable, then the LED is glowing.



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