Ever needed an application where the resistance of a resistor needed to vary proportionately in response to a PWM or a varying analog voltage? Yes, this is where an LED-LDR opto-coupler becomes so useful. The following image shows the symbol for a LED LDR opto-coupler. Any other regular opto-coupler, such as an LED/transistor, LED/FET, or […]
LED
Simple RGB LED Controller Circuit
In this post I have explained how to make a simple RGB (Red, Green, Blue) LED controller circuit which may be designated to flash a group of RGB LEDs with a particular sequencing pattern. The idea was requested by Mr. Navdeep. Technical Specifications I want to make a display board with red, green and blue […]
Christmas LED Candle Light Timer Circuit
In this post I have explained a sequentially advancing 25 LED timer circuit which may be initiated on the 1st day of December so that each LED lights up on each day until the 25th of December (on Christmas) when all the 25 LED can be seen lit up. The circuit was requested by Mr. […]
LED Meteor Shower, Rain Tube Circuit
In this post I have explained how to design an intriguing LED light effect that generates a collapsing metor shower like appearance. The idea was requetsed by Mr.Pinto Mondal. Technical Specifications I am very grateful of your work. Sir I want to make a circuit,which available in the market like 1 or 1.5ft long led […]
“WELCOME” LED Display Circuit
In this post I have explained how to make a chasing “WELCOME” display circuit sign board, which illuminates each alphabet sequentially until all the 7 alphabets are lit and then the whole display shuts off, the cycle continues permanently as long as the circuit is powered. Overview I have already discussed a similar concept explaining […]
Simple PIR LED Lamp Circuit
The following PIR LED lamp circuit was designed by me for one of the followers of this blog Mr.Deepak upon his request. The circuit is a LED driver which responds to ambient light as well as to the presence of a human, person or intruder, and varies its illumination accordingly, let’s know more. Technical Specifications “I was looking to […]





