•  
  •  

Factory Siren

This circuit produces a sound similar to a factory siren.
It makes use of a 555 timer Ic used as an astable multivibrator of a center frequency of about 300Hz.
The frequency is controlled by the pin 5 of the IC. When the supply is switched ON, the capacitor charges slowly and this alters the voltage at pin 5 of the IC hence the frequenct gradually increases.

After the capacitor is fully charged, the frequency no longer increases. Now when the push button siren control switch is held depressed, the capacitor discharges and the siren frequency also decreases.

The presets VR1 and VR2 should be adjusted for optimum performance.

If there are any problems please contact webmaster@electronic-circuits-diagrams.com

Please share & like

NATIONAL SEMICONDUCTOR (NSC) VOLTAGE REGULATOR LM340T-12 25 PIECES
$14.0 NATIONAL SEMICONDUCTOR (NSC) VOLTAGE REGULATOR LM340T-12 25 PIECES picture
NEW SHELF STOCK NEW BUSSMANN FWH-80B FWH-80BA 80A/AMP SEMICONDUCTOR FUSE
$24.5 NEW SHELF STOCK NEW BUSSMANN FWH-80B FWH-80BA 80A/AMP SEMICONDUCTOR FUSE picture
Lot of 2000 Fairchild Semiconductor 1011445327+001+014, 22059287, 1092_X10042A T
$649.0 Lot of 2000 Fairchild Semiconductor 1011445327+001+014, 22059287, 1092_X10042A T picture
FAIRCHILD SEMICONDUCTOR TFXPD 6000 PNEUMATIC TRANSDUCER T8631
$600.0 FAIRCHILD SEMICONDUCTOR TFXPD 6000 PNEUMATIC TRANSDUCER T8631 picture
Military Specifications JAN1N3893 Diode Semiconductor Device NSN:5961-01-033-888
$9.99 Military Specifications JAN1N3893 Diode Semiconductor Device NSN:5961-01-033-888 picture