Very Sensitive Fire Alarm Circuit Using Relay

by Utsource123 in Circuits > Sensors

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Very Sensitive Fire Alarm Circuit Using Relay

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Hii friend,

Today I am going to make a circuit of Fire Alarm which is very sensitive.Today I will make this circuit using Relay and Transistor BC547.

Let's get started,

Components Required -

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(1.) Photodiode x1

(2.) Buzzer x1

(3.) Relay - 6V x1

(4.) Transistor - BC547 x1

(5.) Battery clipper x2

(6.) Battery - 9V x2

Transistor - BC547

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This is the pins of this transistor.

C - Collector,

B - Base and

E - Emmiter.

Connect Transistor to Relay

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Firstly we have to connect transistor to the relay.

Solder Collector pin of transistor to coil-1 pin of the Relay as you can see in the picture.

Connect Photodiode

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Next we have to connect Photodiode to the relay.

Solder Cathode leg of Photodiode to Coil-2 pin of Relay and

Anode leg of Photodiode to Base pin of the Relay as solder in the picture.

Connect Battery Clipper Wire

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Next solder +ve wire of battery clipper to Coil-2 of Relay and

Solder -ve wire of battery clipper to emmiter pin of the transistor as you can see in the picture.

Next Connect Buzzer

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Solder -ve pin of buzzer to common pin of the Relay.

Connect Second Battery Clipper

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Now we have to connect second battery clipper wire to the circuit.

Solder +ve wire of battery clipper to +ve pin of buzzer and

solder -ve wire of battery clipper to NO (Normally Open) pin of the Relay as you can see in the picture.

Connect Batteries to Battery Clipper

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How It Works

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When fire will burn around this circuit with distance approx 5Cm then Buzzer will give sound automatically.

NOTE : We can also connect 3V LED to this circuit.Connect 3V LED with 220 ohm resistor in the parallel of Buzzer.

Thank you