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MODIFICATIONS
• HIGHER VOLUME: To increase the volume level, we add a resistor in series with C1 (that's why we
have the holes spaced farther apart!) Simply unsolder one end of C1 and connect to R3, 1.5K (brown-
green-red) as shown:
YELPING SIREN: To make your siren sound like the yelping type (and get a tired pushbutton finger, too!),
change C2 from 47 uF to a smaller value such as 5 or 10 uF. Experiment with different values for the right
rate. You may find extra capacitors in old radios or other devices. If need be, you can even buy them new at
Radio Shack for about 69 cents a pair!
C1
TO HOLES
FOR C1
SM3—6
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