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Useful

9 Useful LDR Circuits Explained

Last Updated on January 2, 2024 by Swagatam 43 Comments

LDR cross section view

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 […]

Filed Under: Sensors and Detectors Tagged With: Circuits, Explained, LDR, Useful

2 Useful Energy Saver Solder Iron Station Circuits

Last Updated on January 19, 2025 by Swagatam 23 Comments

In this post I have explained how to build a energy efficient soldering iron station circuit for achieving maximum power saving from the unit, by ensuring that it is automatically switched OFF when not being used for sometime. Written and Submitted By: Abu-Hafss DESIGN#1: OBJECTIVE To design a circuit for solder iron which would not […]

Filed Under: Temperature Controllers Tagged With: Energy, Iron, Saver, Solder, Station, Useful

5 Useful Motor Dry Run Protector Circuits Explained

Last Updated on September 22, 2024 by Swagatam 272 Comments

motor2Bdry2Brunning2Bpreventor2Bcircuit

The 5 simple dry run protector circuits presented here shows simple methods by which  insufficient water conditions inside an underground tank can be sensed without introducing probes inside the underground tank, and thus preventing any possibility of motor dry running. The circuit also incorporates an overhead water overflow control feature. The idea was requested by […]

Filed Under: Water Controller Tagged With: Circuits, Explained, Motor, Protector, Useful

3 Useful Electronic Mosquito Repellent Circuits Explored

Last Updated on September 25, 2026 by Swagatam 29 Comments

mos rep

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 […]

Filed Under: Pets and Pests Tagged With: Circuits, Electronic, Explored, Mosquito, Repellent, Useful

6 Useful DC Cell phone Charger Circuits Explained

Last Updated on May 17, 2026 by Swagatam 301 Comments

DCcellphonechargercircuit

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 […]

Filed Under: Battery Charger Circuits Tagged With: Cell, Charger, Circuits, DC, Phone, Useful

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