Hi,am a college student doing a project on fire alarm using a thermistor. i humbly need your help in my project and your help will be much appreciated. i need advantages of using this kind of fire alarm. ....etc

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simple touch alarm circuit using ic 555 ppt

Touch the sensor of the alarm with your finger and it starts beeping, goes on for some time and then stops. Touching it again, and it goes again! This little and flexible circuit consists of a touch sensor and a directly coupled transistor amplifier with a small loudspeaker as the output load. Two sensor strips of metal are mounted side by side on a 1 1 cm size micasheet and connected to the input of the circuit.

How the touch alarm works

Under normal conditions no current flows through switching ....etc

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Many fire alarm circuits are presented here,but this time a new circuit using a thermistor and a timer to do the trick. The circuit is as simple and straight forward so that, it can be easily implemented. The thermistor offers a low resistance at high temperature and high resistance at low temperature. This phenomenon is employed here for sensing the fire.

The IC1 (NE555) is configured as a free running oscillator at audio frequency. The transistors T1 and T2 drive IC1. The output (pin 3) of IC1 is couples to base of transistor T3 (SL100), w ....etc

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I urgently need a fire alarm circuit that detects heat using lm35 sensor(using adc to convert analog to digital) and after the temperature exceeds a said limit (say 50deg) the buzzer starts to buzz..please help urgently!! ....etc

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Simple Fire Alarm Circuit
Here is a simple fire alarm circuit based on a LDR and lamp pair for sensing the fire.The alarm works by sensing the smoke produced during fire.The circuit produces an audible alarm when the fire breaks out with smoke.
When there is no smoke the light from the bulb will be directly falling on the LDR.The LDR resistance will be low and so the voltage across it (below .6V).The transistor will be OFF and nothing happens.When there is sufficient smoke to mask the light from falling on LDR, the ....etc

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i need a document about the fire alarm circuit using thermister and ic555
[email protected]
no registration only i need document of fire alarm circuit ....etc

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zigbee based remote controlled robot with wireless video camera abstract
zigbee based remote controlled robot with wireless video camera ....etc

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To get full information or details of circuit diagram of fire alarm using microcontroller 8051 please have a look on the pages

http://circuitstodaywp-content/uploads/2012/10/thermometer-using-8051.png

https://myclassbook.files.wordpress2014/01/digital-voltmeter-using-8051-micrcontroller.jpg

http://electronicshubwp-content/uploads/2013/10/Fire-Alarm-Circuit-Using-Germanium-Diode.jpg

https://myclassbook.files.wordpress2014/04/digital-clock-using-8051-microcontroller-and-lcd-display.jpg?w=490

http://kavediasir.yolasiteresources/Circuit%20to ....etc

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project file content needed for FIRE ALARM CIRCUIT

Working of fire alarm circuit
Working is based on the switching property of transistor.
The thermistor and R1 forms a potential divider network which drives the transistor.
The heart of this circuit is a thermistor. Thermistors are low-cost, easily-available temperature sensors widely used for uncomplicated temperature measurements.
Thermistors are temperature sensitive resistors. When temperature increases resistance offered by the thermistor decreases and vice versa. At normal temperature, t ....etc

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To get full information or details of simple touch alarm circuit please have a look on the pages

http://seminarsprojects.net/Thread-touch-sensitive-alarm

if you again feel trouble on simple touch alarm circuit please reply in that page and ask specific fields in simple touch alarm circuit ....etc

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