Isolation voltage simulation visual indication circuit and method based on optocoupler linear region

Abstract

The invention discloses an isolation voltage simulation visual indication circuit and method based on an optocoupler linear region. The circuit comprises an optocoupler U1, an input current-limiting resistor R1, an indication light-emitting diode LED1 and an output current-limiting resistor R2, a light-emitting diode at the input side of the optical coupler U1 is connected in series with the input current-limiting resistor R1 to form an input loop which is connected to two sides of an isolation voltage input end; the collector electrode of a photo-transistor on the output side of the optical coupler U1 is connected with the cathode of an indication light emitting diode LED1, the anode of the indication light emitting diode LED1 is connected to a working power supply VCC through an output current-limiting resistor R2, and the emitter electrode of the photo-transistor is grounded. According to the invention, the structure is simple, the cost is low, and the linear transmission characteristic of the optical coupler is utilized to carry out continuous and analog visual indication on the DC voltage value of the isolation side through the brightness of the light emitting diode.

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