kemo-kojak siren

Apr 25, 2008 1 Replies
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I have found ,for bicycles of my niece , schematic of a typical kojak siren but without list of components . I thought of finding , by experiment , the close frequency and getting the just values of resistences and capacitors but I cannot well get them ; does anyone , that bought the kit kemo or similar one , know them ? The scheme is here :



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These are my tried values :



R1=R4=R7=R10=R5== 560 OHM R2=r3=R8= R6=r9= 22000 , 2200 ,33000 ,68000



c5=c6 = 22 nano F



C2=C3= 47 micro F



Transistors =bc547 c & bd242


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B

R1 12k R2 100k R3 100k R4 10k R5 47k R6 100k R7 10k R8 100k R9 100k R10 10k

C1 22uF C2 0.47uF C3 0.47uF C4 0.1uF C5 0.01uF C6 0.01uF

Instead of using R11 into T5, you need more drive. Use another npn in a darlington configuration:

View in fixed-width font:

12 o----------------------o------. | | | | | | | | __ /| | '--| | | | .--|__| | R11 | | \\| ___ |/ | From -----|___|------| | Oscillator |> | 100k | | | |/ '----| | |>

.-. | 10k | | | | | | '-' | | | | | 0 o-----------------------o------' (created by AACircuit v1.28.6 beta 04/19/05

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That should scream pretty annoyingly.

Regards, Bob Monsen

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