LED Photo Sensor
Here's a circuit that takes advantage of the photo-voltaic voltage of an ordinary LED. The LED voltage is buffered by a junction FET transistor and then applied to the inverting input of an op-amp with a gain of about 20. This produces a change of about 5 volts at the output from darkness to bright light. The 100K potentiometer can be set so that the output is around 7 volts in darkness and falls to about 2 volts in bright light.
LED Photo Sensor circuit
Title: LED Photo Sensor
electronic circuit
Source: unknown
Published on: 2007-07-21
Reads: 3728
Print version: 
Other electronic circuits and schematics from Motor, light and power control
-
Interfacing 5 volt CMOS to 12 volt/ 25 Watt Loads
-
Sunrise Lamp
-
TRIAC Light Dimmer
-
Optical toggle switch using a single Chip
-
Courtesy Light
-
1.5 Hour Lamp Fader (Sunset Lamp)
-
Automatic Speed Controller for fans & Coolers
-
25 Light Sequencer using Xmas lamps
-
High And Low Voltage Cut Off With Time Delay
-
LASER Transmitter/Receiver