•  
  •  

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


Vintage Tecumseh Ignition Systems Troubleshooting Booklet #694903 picture

Vintage Tecumseh Ignition Systems Troubleshooting Booklet #694903

$8.99



VINTAGE PALMGREN NO.30 2 1/2

VINTAGE PALMGREN NO.30 2 1/2" INCH DRILL PRESS MACHINIST VISE

$44.50



Vintage Letterpress Steel Galley Trays - 9

Vintage Letterpress Steel Galley Trays - 9" x 13"

$9.00



Sanfords King Size Permanent Marker Metal Vtg Nos Old School Smell Lot Orange picture

Sanfords King Size Permanent Marker Metal Vtg Nos Old School Smell Lot Orange

$20.00



Vintage Mitutoyo Outside Micrometer No. 103-262 M120-2

Vintage Mitutoyo Outside Micrometer No. 103-262 M120-2" Made in Japan w/ Case

$35.00



Carbon Composition Resistors – USA Manufactured – NOS – Vintage picture

Carbon Composition Resistors – USA Manufactured – NOS – Vintage

$1.00



Vintage NOS Smith Corona Lift-Rite Typewriter Ribbon Cartridge for Coronamatic. picture

Vintage NOS Smith Corona Lift-Rite Typewriter Ribbon Cartridge for Coronamatic.

$12.95



Colorful Owl Vintage 70's Roach Iron on T-Shirt transfer NOS picture

Colorful Owl Vintage 70's Roach Iron on T-Shirt transfer NOS

$19.95



Ed Hardy Hat, Vintage/ Y2K picture

Ed Hardy Hat, Vintage/ Y2K

$25.00



OHAUS Cent-O-Gram 311 g. Quad Beam Scale In Wooden Box - Portable Rare Vintage picture

OHAUS Cent-O-Gram 311 g. Quad Beam Scale In Wooden Box - Portable Rare Vintage

$225.00