Security Alarm Circuit With High Power Siren

admin October 23, 2018 10 Comments

High Power Siren Security Alarm Circuit


In this article, we have designed a transistor based security alarm circuit with a high power siren that can be used to provide security for homes or as a warning for intruders trespassing. Only the basic design is provided in the circuit. You can check for advanced security alarm circuits using Arduino and Micro-controllers in the links given below.

Related Topics

Sensitive Intruder Alarm Circuit

Burglar Alarm Using 8051 With SMS Alert

Burglar Alarm using Arduino and PIR Sensor

Infrared Motion Detector Circuit

A complementary transistor pair (BC 557 & 337) is arranged as an oscillator, directly drives the speaker. Transistor Q1 (BC 557) is used to provide full charging of capacitor C2. When the push button switch P1 is pressed, capacitor C2 discharges through R8 and the circuit starts oscillating at a low frequency that increases slowly until a high frequency steady tone is reached and it is kept. When P1 is released C2 starts discharging and and output frequency slowly decreases. When C2 is charged fully the circuit stops oscillations. Please note that the pressing of the push button P1 denotes the cause of the siren alarm circuit to activate. This could be interpreted as the presence of a burglar or someone unwanted.


Adjust the values of C2 & R6 to vary the tune. To get a better result for the security alarm circuit, it is highly recommended that you wire the circuit on a good quality PCB. A good quality common board may also do the trick.

Parts List

Component Specification
Resistors, R1 & R31/4W
Resistors, R2 & R51/4W
Resistors, R41/4W
Resistors, R61/4W
Resistors, R7 1/4W
Resistors, R81/4W
Electrolytic Capacitors, C1 & C225V
Polyester or Ceramic Capacitor, C363V
Electrolytic Capacitor, C425V
Transistors, Q1, Q2BC557  
Transistor, Q3BC337  
Toggle or Slide  Switch, SW1SPST 
Pushbutton  Switch, P1SPST 
Speaker, SPKR8 Ohms
Battery, B112V

Siren Circuit Diagram

Security Alarm Circuit With High Power Siren

Security Alarm Circuit With High Power Siren

We have more sound and alarm related circuits in our website,take a look below:

1. Police Siren using NE555

2. Canary Chirp Generator

3. Whistle to Beep Circuit

4. Metronome Generator Circuit

5.  Door Bell Circuit

  • kishore
    February 25, 2017

    do you have the readily available PCB for high power police siren? What is the sound level in dB?

  • Bob Owen
    October 15, 2012

    Hi, I am looking for a high power alarm for my extruder low vacuum alarm. As long as SW1 is lcosed does this alarm repeat until the circuit is re-set?
    Also can i use something different then an 8 ohm speaker?
    What would i need to change to make it a 24 VDC circuit?
    Thanks, Bob

  • Gabor
    July 25, 2011

    Its powerfull, circuit is good 😉

  • DIRK
    June 23, 2011

    high power siren
    wehn pus the button and hold on the bc337 very hot or melting ???

    • Alvin
      November 15, 2016

      Do you have a diagram of super siren using a timer MB544?

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