british police siren | Electronic Schematic Diagram https://electronicscheme.net Schematic Diagram & PCB Design Wed, 24 Sep 2014 08:48:52 +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 british police siren | Electronic Schematic Diagram https://electronicscheme.net 32 32 129969089 British Police Car Siren https://electronicscheme.net/british-police-car-siren/?utm_source=rss&utm_medium=rss&utm_campaign=british-police-car-siren https://electronicscheme.net/british-police-car-siren/#comments Mon, 30 Nov 2009 16:57:27 +0000 http://electronicscheme.net/?p=328 This is the sound generator which will simulate British police car siren. The circuit is built using 2 pieces of timer IC 555 to generate […]

The post British Police Car Siren first appeared on Electronic Schematic Diagram.]]> This is the sound generator which will simulate British police car siren. The circuit is built using 2 pieces of timer IC 555 to generate sound frequency.

British Police Car Siren

How the circuit work:

The 555 on the right is wired as an alarm sound generator and the second 555 timer on the left is a 1 Hz astable multivibrator. The output of the left timer is to modulate the frequency of the right timer. This process will cause the right timers frequency to alternate between 440Hz and 550Hz at a 1 Hz cyclic rate. The transistor 2N3055 is used to amplify the sound signal to the loudspeaker, with transistor type of?2N3055, this circuit should be loudy 🙂 . This circuit should be nice for newbie hobbysts. This circuit works with 12VDC power supply or battery.

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