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freezer alarm buzzer circuit schematic

Sensitive Freezer Alarm with Buzzer

Here is a simple freezer alarm circuit, but ultra sensitive with a buzzer. The circuit raises an audio alert when the temperature inside the freezer box goes up above a preset level. The circuit requires 9V dc supply and can power from a standard 9V alkaline battery.

A negative temperature co-efficient type (NTC type) small thermistor (R1) here works as the freezer status sensor. Related components (T1 and T2) are used to drive a 6 to 9V rated mechanical buzzer. When the sensor detects a temperature shoot, the buzzer starts beeping and remains in that condition, till power to the circuit is removed. For this on/off plus reset function any small dc toggle switch can be inserted at the positive rail.

Freezer Alarm Circuit Schematic

freezer alarm buzzer circuit schematic

2 Comments

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  • KULDEEP PATEL

    PLESE HELP ME IN THIS PROJECT

  • Navinesh

    Please can you give me the detail specification and the design for this circuit as i am doing the project on this here in Fiji. Your help and support would be greatly appreciated.

    Please provide as much as information possible or if there is any other designed circuit i would appreciate to receive.

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