LED turn ON by LDR when dark and LDR and resistor connect in voltage divider circuit. During bright light transistor base get low voltage so transistor stay OFF and during dark come LDR resistance goes down and base voltage goes up with transistor turn ON and LED light up. Hence, this Simple Darkness Detector Circuit […]
Sensors and Detectors
Motion Detector Circuit using IC 555
This easy Motion Detector Circuit uses IC 555 to find human from far, as circuit have two parts: Transmitter: IC 555 work like astable multivibrator and it make square wave signal and this signal goes out through IR sensor (infrared). Receiver: Phototransistor see IR beam and if someone moves and block the beam then phototransistor […]
Simple Non-Contact 220V AC Detector Circuit using IC 555
Playing with electric wire is risky especially if we do not know electronics, also wrong use of electricity can be dangerous. So better to be safe before touching wire and first check if some electricity with leakage voltage is still there. This article for Simple Non-Contact 220V AC Detector Circuit using IC 555 show how […]
Broken Cable Detector Circuit using IC CD 4069
This post is for Broken Cable Detector Circuit using IC CD 4069. In this circuit there is no need to open wire to check, it work like metal finder but find AC current in wire but not in metal. Furthermore, it uses chip CD 4069 and this chip has small switches to turn ON light […]
Touch Alarm Circuit using IC 555
Touch metal part and buzzer makes sound and this uses IC 555 in monostable mode. IC 555 is good for learning in simple circuits and in this Touch Alarm Circuit using IC 555 when someone touches the metal plate then buzzer makes loud alarm. Circuit Working: Parts List: Components Values Quantity Resistors 1M 1/4 watt […]
Tachometer Circuit
This easy to build Tachometer Circuit is a small DIY tool to check speed of rotating shaft or disc; we used tachometer to know how fast shaft or wheel spin in RPS (revolutions per second). Furthermore, this simple circuit uses two 7-segment displays and one slotted opto sensor MOC7811 where all parts are easy to […]