Simple Siren

Simple Siren

The circuit for this project is relatively difficult for beginners as the number of components used is close to about 25. If you are able to assemble this correctly on the breadboard this works perfectly and gives very good siren sound. Watch the video to how the sound can be changed by controlling the Pot.

The circuit assembled on a breadboard.

Please note that the capacitors (white square shaped) C1 and C2 used on the board are with value 33n instead of 22n.

you can watch this video........

REF PART TYPE PART NAME VALUE COUNT  Bat1 BATTERYPACK Battery Pack 3V AA -- 1  C1,2 CAPACITOR Capacitor 22n 22n 2  C3,7 ELECCAPACITOR Electrolytic Capacitor 100uF 100uF 2  C4,5 ELECCAPACITOR Electrolytic Capacitor 22uF 22uF 2  C6 ELECCAPACITOR Electrolytic Capacitor 1uF 1uF 1  LS1 SPEAKER Speaker 8 Ohm 8Ohm 1  R1,3 RESISTOR Resistor 18K 18K 2  R10 RESISTOR Resistor 22K 22K 1  R2 RESISTOR Resistor 39K 39K 1  R4 RESISTOR Resistor 1.2K 1.2K 1  R5 POT Pot Meter 50K 50K 1  R6 RESISTOR Resistor 470Ohm 470Ohm 1  R7 RESISTOR Resistor 6.8K 6.8K 1  R8 RESISTOR Resistor 15K 15K 1  R9 RESISTOR Resistor 2.2K 2.2K 1  TR1,2,4,5 TRANSISTOR Transistor BC547 547BC 4  TR3 TRANSISTOR Transistor BC557 557BC 1

Approximate cost for building this project is Rs 173.00

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Diodes

Diodes

Diodes are components which are polarized. They only allow electrical current to pass through them in one direction. This is useful in that it can be placed in a circuit to prevent electricity from flowing in the wrong direction.

Another thing to keep in mind is that it requires energy to pass through a diode and this results in a drop of voltage. This is typically a loss of about 0.7V. This is important to keep in mind for later when we talk about a special form of diodes called LEDs.

The ring found on one end of the diode indicates the side of the diode which connects to ground. This is the cathode. It then follows that the other side connects to power. This side is the anode.

The part number of the diode is typically written on it, and you can find out its various electrical properties by looking up its datasheet.

They are represented in schematic as a line with a triangle pointing at it. The line is that side which connected to ground and the bottom of the triangle connects to power.

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