Electronic Siren Circuit using OP-Amp 741

Here is an inexpensive electronic siren circuit built around the most popular and low-cost IC 741. The circuit is basically a square wave generator that is used here to produce the tone of a siren.

Circuit Description of Electronic Siren Circuit using OP-Amp 741

The IC1 is used as a low-frequency multivibrator, the output of which modulates the high-frequency tone produced by the IC2 multivibrator. The final output is amplified and converted into a loud siren by transistor T1 and the speaker.

circuit diagram of electronics siren

Various interesting tones can be obtained by changing the values of capacitors C1 and C2 and resistors R2 and R6. If the value of C1 is increased, the siren will produce sounds like that of a fire engine.

Check out other various different sound generator posted on bestengineeringprojects.com

  1. Grasshopper Sound Generator Circuit using 555 Timer IC
  2. Multi Sound Generator Circuit
  3. Wind Sound Generator Using IC 741
  4. Rain Sound Generator
  5. Machine Sound Generator Using 555 Timer IC

PARTS LIST OF ELECTRONICS SIREN CIRCUIT USING OP-AMP 741

Resistor (all ¼-watt, ± 5% Carbon)

R1 = 10 KΩ

R2 = 1 MΩ

R3 – R9 = 100K

R10 = 1 KΩ

Capacitors

C1, C2 = 0.01 µF (Ceramic Disc)

C3 = 0.001 µF (Ceramic Disc)

Semiconductors

IC1, IC2 = 741 (General Purpose Operation Amplifier)

T1 = 2N1481 (Silicon Bipolar Power Transistor)

Miscellaneous

Output transformer

LS1 = 4Ω loudspeaker

2 Thoughts to “Electronic Siren Circuit using OP-Amp 741”

  1. Clair Morrill

    what value is the ouput transformer?

    1. The transformer should be able to drive a 4-ohm loudspeaker.

Leave a Comment