Hee-haw


Posted on Apr 20, 2012

The circuit uses two gates of a 7400 IC cross-connected to form an astable multivibrator driven by the 1-pulse per second output of the digital clock IC. The hee-haw circuit has a low frequency astable modulator added to make a self-contained European-type siren. Tone and rate can be varied as desired by changing capacitor values.


Hee-haw
Click here to download the full size of the above Circuit.

If the tone is too harsh, a simple R-C filter will remove the harmonic content— the multivibrator output is almost a square wave. With the resistor values shown, no startup problems occur; but if the 2.2 k or 2.7 k resistors are changed too much, latch-up can be a problem.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    A high-performance FM receiver for audio and digital applicatons
    Transistor tester circuit
    Smoke-detector
    make this simple delay on circuit
    High Side Current Monitor
    13.8V 20A linear power supply
    Capacitive level measuring circuit
    Break burglar alarm circuit II
    Fast charging circuit TEA1102



    Top