Light sensor circuit diagrams

LED Photo Sensor.
January 16, 2011

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... [more]

Light/Dark Detector
December 2, 2010

This handy little circuit can tell the difference between darkness and light, making it very useful for switching on and off signs, porch lights or other things when it gets dark or light. [more]

Simple optical switch
November 30, 2010

The 555 is proved to be the most versatile and ubiquitous IC all over the world.This is a possible use: simple inverting schmitt trigger. [more]

Photo Electric Street Light
October 4, 2010

This is basically a Schmitt Trigger circuit which receives input from a cadmium sulfide photo cell and controls a relay that can be used to switch off and on a street lamp at dawn and... [more]

Pinewood Derby Finish Line Lamps
October 4, 2010

The finish line circuit detects the first of three cars to cross the line and illuminates a 25 watt 120 VAC lamp indicating the winning lane. Three photo transistors are used which can be embedded... [more]

Automatic Light Controller Using 7806
October 3, 2010

Voltage regulator ICs (78xx series) provide a steady output voltage, as against a widely fluctuating input supply, when the common terminal is grounded. Any voltage about zero volt (ground) connected in the common terminal is... [more]

circuit from:http://www.extremecircuits.net/2010/05/automatic-light-controller-using-7806.html

Fully Automatic Emergency Light
October 3, 2010

The circuit can be divided into inverter and charger sections. The inverter section is built around timer NE555, while the charger section is built around 3-terminal adjustable regulator LM317. In the inverter section, NE555 is... [more]

circuit from:http://www.extremecircuits.net/2010/05/fully-automatic-emergency-light.html

Using LED As A Light Sensor
October 2, 2010

This circuit shows how to use an ordinary LED as a light sensor. It makes use of the photovoltaic voltage developed across the LED when it is exposed to light. LEDs are cheaper than photodiodes... [more]

circuit from:http://www.extremecircuits.net/2010/05/using-led-as-light-sensor.html

Dark Activated Terrace Lamp
September 27, 2010

This device allows one or more lamps to illuminate at sunset and turn off at dawn.Q1 and Q2 form a trigger device for the SCR, providing short pulses at 100Hz frequency. Pulse duration is set... [more]

circuit from:http://www.extremecircuits.net/2009/06/dark-activated-terrace-lamp_19.html

Light switch

June 23, 2010

This project will let you make a switch that will be activated by light falling on a sensor. It is a very useful device and can be used in automatism’s, security systems, counters, remote controls... [more]