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Alarm

Make this Simple Refrigerator Door Open Alarm Circuit

Last Updated on January 3, 2024 by Swagatam 25 Comments

This presented refrigerator door open alarm circuit which alerts you after a period of time whenever your refrigerator door is left open. This circuit becomes very handy, because in case the door is left due to carelessness may cause significant increase in the consumption and affect the life of the fridge. Circuit Operation This circuit […]

Filed Under: Security and Alarm Tagged With: Alarm, Door, Open, Refrigerator, Simple

Power Switch ON Alarm with Auto OFF Circuit

Last Updated on July 6, 2019 by Swagatam 17 Comments

In this post I have explained a simple monostable based power switch ON alarm circuit which automatically switches OFF after an adjustable preset delay. The idea was requested by Mr. Will Boswell. Technical Specifications Hi there, my name is Will Boswell. I am currently working on a project that involves adding an alarm sounder to […]

Filed Under: Security and Alarm Tagged With: Alarm, Auto, OFF, ON, Power, Switch

Laptop Anti-theft Security Alarm Circuit

Last Updated on July 7, 2019 by Swagatam Leave a Comment

antitheftcircuit

In this post I have explained a simple laptop anti-theft alarm circuit which can used with any concerned object such as a laptop which needs to be protected, when an intruder tries to approach the unit or makes an attempt to steal it the connected alarm is instantly raised. The idea was requested by one […]

Filed Under: Security and Alarm Tagged With: Alarm, Anti, Laptop, Security, Theft

Simple Water Heater Alarm Circuit

Last Updated on January 2, 2024 by Swagatam 1 Comment

buzzer with timer circuit

In this post I have explained a simple water heater alarm circuit which may be used as a safety device for getting indications regarding the switched position of a water heater or a geyser through intermittent buzzer actuation. The idea was requested by Mr. Mathew. Technical Specifications To be frank i am new to your […]

Filed Under: Security and Alarm Tagged With: Alarm, Heater, Simple, Water

Alarm Signal Generator IC ZSD100 Datasheet, Application

Last Updated on May 18, 2026 by Swagatam 10 Comments

speaker alarm circuit

The ZSD100 is an alarm frequency generator IC which incorporates a frequency swept alarm signal generator designed solely for fixed and vehicle protection alarm systems. Circuit Operation For acquiring the specified alarm sound from this IC, just a single ZSD100, two timing capacitors, an in-expensive TO92 darlington, piezo transducer and coupling transformer is everything that […]

Filed Under: Datasheets and Components Tagged With: Alarm, Application, Datasheet, Generator, Signal, ZSD100

Vehicle Speed Limit Alarm Circuit

Last Updated on May 16, 2026 by Swagatam 20 Comments

In our previous articles we have learned comprehensively regarding the ICs LM2907/LM2917 which are fundamentally frequency to voltage converter ICs, and are ideally applicable in all such relevant fields. Here we see how the same chip can be applied for making a vehicle speed limit alarm circuit. Using a Single IC for Speed Detection As […]

Filed Under: Automobile Electronics Tagged With: Alarm, Limit, Speed, Vehicle

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