Page 9 Light Dependent Resistor Electronic Circuits

Light Dependent Resistor Circuits / Photocell Circuits
Light Dependent Circuits: # - C D - H I- N O- Z

Last Updated: June 02, 2021 05:07 AM

Circuits Designed by Dave Johnson, P.E. :

Line-Powered Xenon Flash Transmitter - This line powered xenon flash circuit drives a small camera type flash tube. It has an optical isolator to allow the flash to be safely triggered from some remote device. A flash rate of 2Hz is possible with the circuit . . . [Circuit by David Johnson P.E., 06/03/00]
Low Power 40KHz Light Detector - This circuit is designed for detecting infrared light modulated at around 40KHz. It’s feedback scheme cancels much of the DC component from ambient light. It’s conversion factor is about 100 millivolts per microwatt of 900nm light. . . . [Circuit by David A. Johnson P.E., 07/11/06]
Low Power Amp Monitors Light - The circuit below takes advantage of a low power op amp with a “rail to rail” feature. The single resistor R1 defines the light sensitivity of the circuit. The output voltage is directly proportional to the intensity of light striking the small photodiode . . . [Circuit by David A. Johnson P.E., 08/29/10]
Low-power optical interrupter - This circuit is great for battery-powered systems that use slotted type optical interrupters. It draws only 10uA from a 3v battery that should allow up to 5 years of operation from a lithium battery . . . [Circuit by David Johnson P.E., 06/04/00]
Micro Power 40Khz Burst Laser Diode Driver - Some laser tag or simulated combat games can use this circuit to send short bursts of modulated laser light at the opponent's vest, equipped with a matching light receiver. The circuit operates from three 1. 5v cells (4. 5v) that should provide enough energy . . . [Circuit by David Johnson P.E., 06/04/00]
Modified Cheap Solar LED Path Light - Modification of a typical solar path light with a standard 1000ma-hour NiMH AAA cell. I then replaced the small 4 cell solar panel with a larger 4 cell unit, which produced 150ma in the sun. Next, I simply changed the 470uH coil on the circuit board to a 22uH coil. The lower inductance increased the battery current to 40ma when the LED light was on, which translated to about 13ma LED current. The light was much brighter . . . [Circuit by David Johnson P.E., 10/26/12]
Modified LED Night Light - I bought some night lights a few months ago from Walmart here in Denver. The devices were made by Elumina Lighting Technologies Inc. (www. eluminalighting. com) , their model LED-6200A. I think I paid about $15 for a pack of three lights. I wanted a light . . . [Hobby Circuit designed by David Johnson P.E., 05/21/07]
Modulated Light Monitor #1 - This battery powered circuit will work from DC to 500KHz. It is designed to connect to an oscilloscope to monitor the light level changes and modulated signals . . . [Circuit by David Johnson P.E., 07/09/06]
Modulated light receiver circuit - The circuit uses a very inexpensive C-MOS IC that is connected to a small photodiode. Using a unique inductive feedback network, the circuit provides high sensitivity under high ambient light conditions. It is a great circuit when you want to extend the range of an optical remote control transmitter . . . [Circuit by David Johnson P.E., 06/04/00]
Monitor Clear Fluids - This circuit detects when a clear fluid is inside a piece of clear plastic tubing. It can be used for fluid level control and monitoring . . . [Circuit by David A. Johnson P.E., 05/01/12]
Night Light from White LED - As many of you know, I have a pet peeve with poorly made LED night lights. Often, the light from the LED quickly fades, so within months, the light is useless. I have posted several versions of modified night lights using higher quality components . . . [Circuit by David A. Johnson P.E., 11/06/08]

Got Designs?
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Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:
	Light-Operated Doorbell - Light-dependent switches are used in automatic hand-dryers and flushers in toilets. Here is a simple light-operated switch that works in normal light also. You can affix it on the main door of your house to work as an automatic doorbell or a thief alarm. The bell rings as soon as someone’s shadow falls on the sensor of this device. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved] Light-Operated Internal Door Latch - Using this light-operated circuit, you can close or open the door of your room remotely from your bed. You just have to focus the torchlight on the light-dependent resistor of the circuit, which you can install inside your room at a suitable position. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved]
Light-Sensitive Alarm - The circuit detects a sudden shadow falling on a light-sensor and sounds a bleeper for a short time (adjustable). Normal lighting can be used, but the circuit will work best if a beam of light is arranged to fall on the light-sensor. Breaking this beam will then cause the bleeper to sound. . . [Designed by John Hewes] Line-Powered Xenon Flash Transmitter - This line powered xenon flash circuit drives a small camera type flash tube. It has an optical isolator to allow the flash to be safely triggered from some remote device. A flash rate of 2Hz is possible with the circuit . . . [Circuit by David Johnson P.E., 06/03/00] Low Power 40KHz Light Detector - This circuit is designed for detecting infrared light modulated at around 40KHz. It’s feedback scheme cancels much of the DC component from ambient light. It’s conversion factor is about 100 millivolts per microwatt of 900nm light. . . . [Circuit by David A. Johnson P.E., 07/11/06] Low Power Amp Monitors Light - The circuit below takes advantage of a low power op amp with a “rail to rail” feature. The single resistor R1 defines the light sensitivity of the circuit. The output voltage is directly proportional to the intensity of light striking the small photodiode . . . [Circuit by David A. Johnson P.E., 08/29/10] Low-power optical interrupter - This circuit is great for battery-powered systems that use slotted type optical interrupters. It draws only 10uA from a 3v battery that should allow up to 5 years of operation from a lithium battery . . . [Circuit by David Johnson P.E., 06/04/00] Micro Power 40Khz Burst Laser Diode Driver - Some laser tag or simulated combat games can use this circuit to send short bursts of modulated laser light at the opponent's vest, equipped with a matching light receiver. The circuit operates from three 1. 5v cells (4. 5v) that should provide enough energy . . . [Circuit by David Johnson P.E., 06/04/00] Modified Cheap Solar LED Path Light - Modification of a typical solar path light with a standard 1000ma-hour NiMH AAA cell. I then replaced the small 4 cell solar panel with a larger 4 cell unit, which produced 150ma in the sun. Next, I simply changed the 470uH coil on the circuit board to a 22uH coil. The lower inductance increased the battery current to 40ma when the LED light was on, which translated to about 13ma LED current. The light was much brighter . . . [Circuit by David Johnson P.E., 10/26/12] Modified LED Night Light - I bought some night lights a few months ago from Walmart here in Denver. The devices were made by Elumina Lighting Technologies Inc. (www. eluminalighting. com) , their model LED-6200A. I think I paid about $15 for a pack of three lights. I wanted a light . . . [Hobby Circuit designed by David Johnson P.E., 05/21/07] Modulated Light Monitor #1 - This battery powered circuit will work from DC to 500KHz. It is designed to connect to an oscilloscope to monitor the light level changes and modulated signals . . . [Circuit by David Johnson P.E., 07/09/06] Modulated light receiver circuit - The circuit uses a very inexpensive C-MOS IC that is connected to a small photodiode. Using a unique inductive feedback network, the circuit provides high sensitivity under high ambient light conditions. It is a great circuit when you want to extend the range of an optical remote control transmitter . . . [Circuit by David Johnson P.E., 06/04/00] Monitor Clear Fluids - This circuit detects when a clear fluid is inside a piece of clear plastic tubing. It can be used for fluid level control and monitoring . . . [Circuit by David A. Johnson P.E., 05/01/12] New Lightning Detector - Especially built for the beginner. . . [Charles Wenzel (unless otherwise noted)] Night Light - The two transistors are used as a direct coupled switch, Adam used 2SC711 but any general purpose transistor will do e. g. 2N3904, BC109C. The CDS photocell, type ORP12 is normally illuminated, therefore its resistance is low. The 50k control, the 1k resistor and the photocell form a potential divider which biases the first transistor. This transistor is on, its collector being held low, turns the last transistor and hence lamp and relay off. . . [Andy Collison's website] Night Light from White LED - As many of you know, I have a pet peeve with poorly made LED night lights. Often, the light from the LED quickly fades, so within months, the light is useless. I have posted several versions of modified night lights using higher quality components . . . [Circuit by David A. Johnson P.E., 11/06/08] Night Vision Enhancer - Here is a simple green LED flashlight built around 555 timer IC (IC1) and powered from a 3V battery pack. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved] Night-Light Uses A Photoresistor to Detect Dusk - 12/15/11 EDN Design Idea You can adjust this battery-powered circuit for different levels. . . [by Chau Tran, Analog Devices, Malden, MA] Night-Vision Digital Goggle - By wearing this digital goggle, light vehicle drivers can drive the vehicle easily without any glare problem. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved] <<<<Previous PAGE

Light Dependent Resistor Circuits / Photocell Circuits
Light Dependent Circuits: # - C D - H I- N O- Z