In this mode of operation, the capacitor C1 charges through the resistors R2 and R3 up to the 2/3 value of VCC, and during this time the Pin3 remains high while the capacitor discharges up to 1/3 of the VCC through the resistor R3 and the Pin3, during this time remains low. In this circuit, 555 IC is configured in the astable mode for a buzzer to generate sound oscillations. Here we have built a circuit using a thermistor, 555 timer IC, NPN transistor, and a few other components to operate. The resistance is inversely proportional to the temperature. The major component of the circuit is the temperature sensing element such as a thermistor which is a temperature sensing resistor and changes resistance according to the temperature. The fire alarm system is one of the crucial needs in these kinds of industrial sector, but the residential and commercial sector also utilizes such systems to ensure safety.Ī fire alarm system is designed to aware people of fire, smoke, carbon monoxide, or any other emergency so that necessary action can be taken. These types of industries or gas stations use proper alarm systems for emergencies.

Almost all the industrial sector works with heavy machinery and crucial mechanical and electrical devices which are sensitive to be handled and a minor mishandling or technical issue can cost several lives and a severe loss of money.

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