

Fridge Alert System
Here is a simple circuit “Fridge Alert System” can be used in fridge, indicating whether the temperature is more than pre-defined temperature. The arrangement of the circuit fridge alert system showed here alert when temperature increased then 50C.
Thermistor TH1 is used as temperature sensor, change their resistance whenever changes in surrounding temperature. IC1 CL7611 combined with thermistor to complete all the process of temperature. IC2 is used here to indicate the status of battery. Glowing LED1 indicate temperature is more than 50C.
PARTS LIST
Resistors (all ¼-watt, ± 5% Carbon)
R1, R2 = 4.7 MΩ
R3 = 2.2 MΩ
R4 = 56 KΩ
R5 = 12 KΩ
R6 = 10 KΩ
R7 = 270 Ω
R8 = 390 Ω
Semiconductors
IC1 = CL7611
IC2 = 8211
T1 = 2TX300
LED1 = RED
LED2 = Green
Miscellaneous
SW1 = Push-to-on switch
TH1 = GL16 thermistor
Ect
automatic temperature control aircondition of fridge