Fridge Alarm with 4060


Posted on Apr 5, 2012

This circuit, enclosed into a small box, is placed in the fridge near the lamp (if any) or the opening. With the door closed the interior of the fridge is in the dark, the photo resistor R2 presents a high resistance (>200K) thus clamping IC1 by holding pin 12 high.


Fridge Alarm with 4060
Click here to download the full size of the above Circuit.

When a beam of light enters from the opening, or the fridge lamp illuminates, the photo resistor lowers its resistance (<2K), pin 12 goes low, IC1 starts counting and, after a preset delay (20 seconds in this case) the piezo sounder beeps for 20 sec. t




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Amplified Noise Limiter For Sw Receivers Circuit
12V voltage doubler circuit
LED Emergency Light Circuit With Battery Over Charge Protection
Fire Fighting Robot
One light emitting diode display circuit
UGN-3501T counter circuit diagram of a Hall sensor
Infrared remote control dimmer light circuit diagram



Top