Optical communication system

Posted on Nov 4, 2012

The simple modulator stage will accommodate most common LEDs. By adjusting the potentiometer, the bias of the transistor is varied until the LED is at its half output point. Then, audio will cause it to vary above and below this point

Optical communication system
Click here to download the full size of the above Circuit.

The purpose of Rl is to limit the current through the LED to a safe level and the purpose of the 10 ohm resistor is to allow a portion of the modulating signal to be observed on a scope.

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