In this modern era, the Fire Alarm circuit has great importance in different places. This includes banks, architecture, modern buildings, data centers, and even homes, and warehouses where storage and protection of various types of goods are the main concern for security.
The Fire Alarm Circuit is the most efficient, simple, and less complex circuit. As it requires less equipment for its design. The fire alarm circuit produces a sound when firing attacks industries. So that preventive measures can be taken. The fire alarm circuit acts as a lifesaver. The simple Fire alarm circuit uses 555 Timer IC to sense the fire or any kind of rise in temperature. And triggers an alarm.
Hardware Components
The following components are required to make a Fire Alarm Circuit
| S. NO | Component | Value | Qty |
|---|---|---|---|
| 1. | Battery | 9v | 1 |
| 2. | IC | NE555 Timer | 1 |
| 3. | NPN Transistor | BC547 | 1 |
| 4. | Thermistor | 10K | 1 |
| 5. | Resistors | 1k, 100k, 4.7k | 1, 2, 1 |
| 6. | Variable Resistor | 1M | 1 |
| 7. | Electrolytic Capacitor | 10uF | 1 |
| 8. | Buzzer | – | 1 |
555 IC Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer
Circuit Diagram
Working Explanation
The working of the Fire Alarm circuit is very simple and easily understandable. The 555 Timer IC operates in an astable mode in the Fire Alarm circuit. With the help of this, the buzzer at the output should produce an oscillating sound. The Thermistor has a maximum resistance when there is no fire which keeps the transistor ON. But due to low voltages, the transistor remains unable to drive 555 Timer IC. So the buzzer remains in OFF condition. In another case when there is a fire or any kind of increment in the temperature the resistance of a thermistor decreases. This decreases the voltages of the base terminal of the transistor and it turns OFF. As the reset pin of 555 Timer IC receives the positive voltage it drives the buzzer and it starts beeping.
Application
- Banks
- Modern Buildings
- Data Centers
