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Sci.Electronics.Basics -> kemo-kojak siren
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Author: *paolino Q*Date: 09:27 25-04-08
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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 :
http://attach.mynl.it/img?id=NzQ0Ng
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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Author: Bob MonsenDate: 13:36 25-04-08
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"*paolino Q*" <senzaparole@tiscali.it> wrote in message
news:4811dc53$0$29973$5fc30a8@news.tiscali.it...
>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 :
>
> http://attach.mynl.it/img?id=NzQ0Ng
>
> 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
>
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------.
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| | __ /|
| '--| | |
| .--|__| |
R11 | | \|
___ |/ |
From -----|___|------| |
Oscillator |> |
100k | |
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'----|
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.-. |
10k | | |
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'-' |
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0 o-----------------------o------'
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
That should scream pretty annoyingly.
Regards,
Bob Monsen
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