## Thursday, July 18, 2013

### Electronic Circuit Schematic of Fire Detection and Indicator using Thermistor and IC NE555

Robometricschool. - As we know there are many fire that cause casualties and property. Minimum in fire indicator can causes many people not ready to save their possessions and even their lives. So in here we think to give solution with indicator when on fire.

So in here we will give you simple electronic circuit of fire detection and indicator using thermistor as fire detection and IC NE555 as oscillator to make fire indicator. And this electronic circuit schematic can work effective when fire occur in your place.

Electronic Schematic of Fire Detection and Indicator

 Figure 1. Electronic Circuit of Fire Detection and Indicator

Component Lists

1. R1 -------------- 470
2. R2 -------------- 33K
3. R3 -------------- 470
4. R4 -------------- 560
5. R5 -------------- 47K
6. R6 -------------- 2K2
7. R7 -------------- 470
8. VR1 ------------ 100K
9. D1 -------------- LED
10. D2 -------------- IN 4002
11. C1 -------------- 10uF/16V
12. C2 -------------- 0.01uF
13. C3 -------------- 0.01uF
14. T1 --------------- C828
15. T2 --------------- A733
16. T3 --------------- D400
17. U1 -------------- NE555
18. S1 -------------- SPEAKER 2.5"
19. RT1 ------------ Thermistor

Circuit Performance

To know how are electronic circuit schematic of Fire Detection and Indicator work, we will description as follow:
1. As the fire detection component in electronic circuit schematic of Fire Detection and Indicator is Thermistor RT1. Thermistor is heat detection that also can be used to detect on fire. Thermistor will change their resistance when this component detect heat on fire. And the changing of this resistance we will use to find changing of voltage divider after connected with VR1 100K ohm.
2. When thermistor detect heat on fire it will make active voltage to trigger T1. T1 will active and work like close switching. And the T2 will get low voltage that will make T2 active because T2 is PNP transistor.
3. With T2 active, it will make IC1 NE555 triggered and also active to give signal to output in pin 3. And then it will make T3 will closed and will make speaker is active to give us sound as fire indicator. So it is very simple work of Fire Detection and Indicator.