2N3702 | Electronic Schematic Diagram https://electronicscheme.net Schematic Diagram & PCB Design Tue, 30 Sep 2014 05:14:33 +0000 en-US hourly 1 https://i0.wp.com/electronicscheme.net/wp-content/uploads/2017/05/cropped-transparent_text_effect.png?fit=32%2C32&ssl=1 2N3702 | Electronic Schematic Diagram https://electronicscheme.net 32 32 129969089 Wailing Alarm Siren https://electronicscheme.net/wailing-alarm-siren/?utm_source=rss&utm_medium=rss&utm_campaign=wailing-alarm-siren https://electronicscheme.net/wailing-alarm-siren/#comments Tue, 29 Dec 2009 12:23:42 +0000 http://electronicscheme.net/?p=362 Here is the wailing alarm siren circuit diagram: Components List: R1,R5___________ 4.7K R2______________ 47K R3______________ 10K R4______________ 100K Rx______________ *see text C1,C4__________ 100uF/25V, electrolytic C2,C3__________ […]

The post Wailing Alarm Siren first appeared on Electronic Schematic Diagram.]]> Here is the wailing alarm siren circuit diagram:

Wailing Alarm Siren circuit diagram

Components List:

R1,R5___________ 4.7K
R2______________ 47K
R3______________ 10K
R4______________ 100K
Rx______________ *see text
 
C1,C4__________ 100uF/25V, electrolytic
C2,C3__________ 0.01uF (10nF), ceramic
T1_____________ 2N3702 (NTE159, TUP, etc.)
IC1,IC2________ LM/NE555, MC1455P, etc
LS_____________ Loudspeaker


This alarm circuit uses timer IC to generate frequency. The circuit has wide range supply voltage 5V to 15V DC.

*The Loudspeaker LS and the resistor marked “Rx” should be together 75 ohms. If you have a standard 8-ohm speaker then Rx is 67 ohms. The nearest value is 68 ohms. So for a 8 ohm loudspeaker Rx is 68 ohms. For a 4 ohm loudspeaker Rx is 71 ohms, for a 25 ohm loudspeaker Rx is 50 ohms, etc.

circuit diagram by Tony van Roon,
source: http://www.sentex.ca/~mec1995/circ/wailing.htm

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