Basic simple fire alarm circuit diagram. When there is no smoke the light from the bulb will be directly falling on the ldr. The simple fire alarm system is one of the innovative solderless breadboard projects. Each new head possesses an address which conveys its exact location.
Typically installers must put in new heads pull some extra wire and insert new printed circuit cards into the existing control panel. First connect the 10 kw potentiometer to the inverting terminal of the lm358 op amp. Simple fire alarm thermistor circuit diagram.
Fire alarm system block diagram. The design of the fire alarm circuit with siren sound is very simple. This simple fire alarm circuit can be used as a indicator or warning circuit for excessive fire.
Working of fire alarm circuit. Consider the temperature of the atmosphere is around 250c and then the resistance of thermistor is high so the voltage across the thermistor is also high according to the basic ohms law vir. This phenomenon is employed here for sensing the fire.
One end of the pot is connected to 5v other end is connected to gnd and the wiper terminal is connected to pin 2 of op amp. This fire alarm project block diagram consists of thermistor transistor indicator and battery. The block diagram of fire alarm circuit block diagram can be estimated based on the requirement and application of project.
The alarm works by sensing the smoke produced during fire. Here is a simple fire alarm circuit based on a light dependent resistor ldr and lamp pair for sensing the fire. Understanding basic fire alarm systems.
The circuit produces an audible alarm when the fire breaks out with smoke. Home security alarm system circuit diagram gallery of electronic circuits and projects providing lot of diy circuit diagrams robotics microcontroller projects electronic development tools. Basic electronics engineering circuits labs theories etc join us categories.
The outputpin 3 of ic1 is couples to base of transistor t3sl100 which drives the speaker to generate alarm sound. The alarm works by sensing the smoke produced during fire. The key component of the circuit is thermistor which has been used as fire detector or fire sensor.
Share on tumblr simple fire alarm circuit designed by using 10k ntc negative temperature coefficient thermistor and timer ic 555 this circuit will produce buzzer sound when the temperature near thermistor raises beyond threshold and this threshold limit can be varied by using variable resistor. The ic1 is configured as a free running oscillator at audio frequencythe transistors t1 and t2 drive ic1. You may be asking yourself if this means a spare head has to be kept in inventory for each.
The transistor is turned on by the voltage drop across the resistor r1.