05-04-2017, 11:56 AM
Fire alarm with thermistor
Fire alarms are primary needs in modern buildings and architectures, especially in banks, data centers and gas stations. They detect fire in the environment at a very early stage by detecting smoke or heat and raise an alarm warning people about the fire and provide ample time to take preventative measures. Not only does it prevent large losses caused by a deadly fire, but sometimes it proves to be life-savers. Here we are building a simple fire alarm system with the help of 555 Timer IC, which will detect the fire (increase in temperature in the environment) and activate the alarm.
The key component of the circuit is the thermistor, which has been used as a fire detector or fire sensor. The thermistor is a temperature sensitive resistor whose resistance changes according to temperature, its resistance decreases with increasing temperature and vice versa.
Applications of thermistors
• A thermistor is used to measure the temperature.
• The thermistor is used as an electrical circuit component
• For temperature compensation
• Circuit protection
• Voltage regulation
• Time Delay, and Volume Control.
• Thermistors are used in automotive applications
• Instrumentation and Communication
• Consumer electronics
• Food handling and processing
• Industrial electronics
• Medical Electronics
• Military and aerospace