Alarm Circuits

Posted on Feb 7, 2014

High Power Siren Circuit This article is all about a comparatively strong siren circuit useful for any purpose. 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 P1 is pressed, C2 discharges through R8 and

Alarm Circuits
Click here to download the full size of the above Circuit.

the circuit starts oscillating at a low frequency that increases slowly until a high frequency steady tone is reached and it is kept. When P2 is released C2 starts discharging and and output frequency slowly decreases. When C2 is charged fully the circuit stops oscillations. Tips. Adjust the

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    traffic light circuit diagram
    Pulse Generator using Op-Amp
    TDA7541 AM/FM Car Radio Tuner IC With Stereo Decoder And Intelligent Selectivity System
    amplifier circuit
    DIY TCI + CDI Trigger
    The local oscillator for 10.7 to 2.5MHz conversion