ES-03       Mini Siren    (DC 9V)     150 ~ 200mA @ 9V


This kit produces a warble siren sound when connected to a 9V battery.  No IC were used in  the circuit.   Only 5 transistors & some passive components.  Transistors Q3 & Q4 are configured as a  astable flip-flop which generates a fixed tone. Transistors Q1 & Q2 form a saw-tooth wave generator which modulates the frequency of the tone generated by Q3 & Q4 thereby creating a warble siren sound.  Ideal for used as sound indicator or audible warning device 

 
( 2 1/4 in speaker & 9V battery clip included )

 

 

   
     PCB size : 50 x 35mm