In this post I have explained 9 LDR circuit projects that uses LDR light sensor to trigger a load ON/OFF through a relay. These circuits are mostly triggered by the absence or the presence of light on the LDR. The circuits are built using transistors, op amps and LDR along with a switching relay. Let’s […]
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3 Useful Electronic Mosquito Repellent Circuits Explored
In this post I have explained the construction of 3 simple electronic high frequency mosquito repellent circuits, which are specially designed to drive away mosquitoes through their tuned high frequency pulses. Design#1: Using a Single CMOS IC Mosquitoes are definitely a nuisance for your summer nights, especially when humidity prevails. Electronic mosquito repellent techniques can […]
3 Useful Temperature Alarm Circuits Explained
In this post I have explained the working of 3 interesting and useful temperature alarm circuits through detailed circuit diagrams. A temperature alarm circuit is basically a device which is designed to detect a temperature threshold and sound an alarm as soon the temperature exceeds over, or drops below the desired temperature detection threshold. 1) […]
6 Useful Voltage Controlled Oscillator Circuit Explored
In this post I have explained how to build 6 useful voltage controlled oscillator circuits, using various op amps and integrated circuits. As the name suggests, a voltage controlled oscillator or a VCO circuit is an oscillator circuit whose output frequency can be controlled or varied through an adjustable control voltage input. This means, if […]
6 Useful DC Cell phone Charger Circuits Explained
A DC cell phone or mobile phone charger is a device which charges a cellphone from an available DC supply source. The device converts the unregulated DC source into a constant current and constant voltage output which becomes safe for any mobile phone charging. In this article I have explained how to build DC to […]




