High & Low voltage cut-off with delay& alarm

jacky March 8, 2012 101 Comments
Description. This straight forward circuit will protect electrical appliances from over voltage as well as under voltage. The circuit also produces an alarm when the power supply comes back. An ideal circuit for home to protect your valuable equipments...
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Mosquito repeller power saver

admin February 16, 2012 7 Comments
Description. Almost all liquidator type mosquito repellers are rated 5Watts. It is a pretty energy consuming game  when these repellers are operated through out the night. Even though these liquidators are switched ON and OFF in discrete intervals there...
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Cat repeller circuit

admin February 15, 2012 5 Comments
With this cool cat/dog repeller circuit you could chase the cats  off  from any where you want. In fact, I designed this circuit to chase my cat from my computer table. Most of the animals like cats respond violently...
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Infrared Motion Detector Circuit

admin August 3, 2016 255 Comments
In this tutorial, we have explained how to build a DIY (Do It Yourself) Infrared Motion Detector Circuit using 555 Timer IC, IR Diode, 2 comparator IC’s and other associated components. An Infrared Motion Detector circuit can be designed...
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Low cost fire alarm circuit.

admin January 21, 2014 89 Comments
Description. When there is a fire breakout in the room the temperature increases. This ultra compact and low cost fire alarm senses fire breakout based on this fact. Transistor BC177 (Q1) is used as the fire sensor here. When...
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Rain alarm circuit

admin January 21, 2014 64 Comments
Description. Here is a simple rain alarm circuit that produces an audible alarm when ever rain falls. The rain detector circuit is based on two transistors (Q1 & Q2) and a NE555IC (IC1). The two transistors are wired as...
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Battery Level Indicator

admin March 1, 2011 19 Comments
Simple Battery Level Indicator Description Here is a easy to build low battery level indicator circuit that produces a visible indication by flashing a LED when the battery voltage drops below a predetermined voltage.The circuit is based on Panasonic’s ...
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Light activated switch circuit

admin July 9, 2014 98 Comments
A Simple Light activated switch Description. This is the circuit diagram of a light activated switch based on National Semiconductors comparator IC LM 311 and a LDR. The circuit is based on a voltage comparator circuit wired around IC...
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Light to Frequency converter circuit

jacky February 28, 2011 1 Comment
A simple Light to Frequency Converter Introduction. Here is the circuit diagram of a effective light to frequency converter circuit that can be used for variety of applications such as light intensity measurement,fun etc. The circuit is based on...
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Audio level meter circuit

admin February 28, 2011 2 Comments
Audio Level Meter Description A simple and low cost audio level meter circuit that can be used to measure the audio level of your sound source.This circuit is a valuable tool for those who are interested in audio circuits....
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