infrared detector circuit schematic

Infrared Detector Circuit with PID20

This infrared detector circuit uses a passive IR-detector component PID20. It converts heat radiation into electrical impulses. The output voltage of the PID20 increases when an object comes close to it, this object must be warmer than the surroundings.

The voltage changes at the output of the IR sensor are sensed by the comparators IC2a and IC2b. Once the sensor detects an object (independent of the object’s actual temperature), one of the comparators will turn on the transistor T1. This transistor then closes the relay connected to it. A separate transistor for each comparator can be used so that the sensor will be able to determine whether the object is warmer or colder than the surroundings. The IR detector circuit consumes around 1 mA and the sensor consumes 0.2 mA.

IR detector circuit diagram

infrared detector circuit schematic


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  • nyaonge massinde

    nice project


    I m in EC 5 th sem. i ve selected this circcuit as a part of my project ….
    my problem is that i cuold not get datasheet of pid20 frm any website and in our STATE i have asked to every electronics shop no one having such ic…. so is there any optional ic that can i use in the place of pid20….
    Waiting for reply…
    as my project is not going futher because of this detector part…please try to reply me soon…

    highly greatfull to you….

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