Toy siren


Posted on Mar 25, 2013

This circuit can be built small enough to frt inside a toy. The circuit consists of a relaxation oscillator utilizing one unijunction transistor (2N2646, MU10, TIS43). R2 and C2 determine the frequency of the tone. Pushing the button, SW1 charges up the capacitor and the potential at the junction of R2 and C2 rises, causing an upswing in the frequency of oscillation.


Toy siren
Click here to download the full size of the above Circuit.

On releasing the pushbutton the charge on C2 will drop slowly with a proportional reduction in the frequency of oscillation. Manual operation of the button at intervals of approximately 2 seconds will produce a siren sound.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

PC terminal using a TV
Adjustable sine-wave audio oscillator
Video-signal-clamp
1296Mhz Rf Amplifier
Digital Radar Speedometer
8 Channel software controlled fanbus with PWM
Headphone Audio Amplifier with Balance Control
Simple home audio power amplifier circuit schematic
Digital Slave Flash Trigger PIC 12F675
Electronics as a Hobby
V3.0 MS Build With Pics
Optional Flip inverter circuit
TV by the photosensitive resistor circuit diagram automatic brightness adjustment



Top