Modulated light-beam circuit

Posted on Jul 26, 2012

Feedback control of the phototransistor in this optical detector helps negate the effects of varying ambient light sources. The output of a modulated visible-light LED is detected, amplified, buffered, and fed through a low-pass filter.

Modulated light-beam circuit
Click here to download the full size of the above Circuit.

Ambient light signals below the LED's 10-kHz modulating rate reach the detector's base out of phase with incoming ambient light and cancel the undesired effects.

Leave Comment

characters left:

New Circuits



Popular Circuits

Rc Decade Box Circuit
20 Watts Car Stereo Amplifier Using TDA2004
Drive relay with AVR microcontroller
Reading a voltage divider schematic
An Ionisation Chamber Shield for OpenRelief
4KHz-170MHz Wide Band RF Signal Generator I
Frequency Modulated Sound Card Capture
Blanket internal measurement circuit disconnection
CF1 CF2 main circuit