A fire alarm system usually consists of central control panel, bells or horns and other sensors associated with the burglary functions connect to doors and windows or monitor rooms for motion or body heat. Below schematic shows the design of a Simple Fire Alarm Circuit Diagram using NE555 IC. In this circuit design, the thermistor offers a low resistance at high temperature and high resistance at low temperature. The NE555 IC is configured as a free running oscillator at audio frequency. This simple fire alarm circuit design utilizes a 6V battery or a 6V power supply.
Fire Alarm Circuit Parts List:
R1 ____ 470 Ohm
R2 ____ 33 kOhm
R3 ____ 470 Ohm
R4 ____ 560 Ohm
R5 ____ 47 kOhm
R6 ____ 2.2 kOhm
R7 ____ 470 Ohm
R8 ____ 470 Ohm
C1 ____ 10 uF
C2 ____ 0.04 uF
C3 ____ 0.01 uF
T1 ____ BC548
T2 ____ BC558
T3 ____ SL100B
Other
LED1
NE555 IC
Thermistor
Speaker 8 Ohm, 1 Watt
Power source/battery 6 Volt
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1 comment for this entry ↓
1 Ademola // Mar 23, 2011 at 2:42 am
The circuit is well desing and used it is good
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