How to build Ambulance siren circuit

Ambulance Siren

You are familiar with the siren attached to various ambulance vehicles. There are various siren sounds attached to different types of vehicles such as medical ambulances, fire ambulances and police ambulances. They produce different varieties of siren sounds to distinguish which vehicle is running on the roads. Here is a simple circuit designed to produce a pleasing siren sound that can be fixed according to the taste of the user.  

Ambulance circuit design

This circuit design employs IC 556. It is a 14 pin dual timer IC. Yes, two IC 555s are combined in a single package.  The first part acts as a frequency generator and the second part functions as a tone generator and amplifier.  It works on a wide voltage source from 6 to 12 V DC. Hence a general-purpose power supply can be used for this gadget. It is a simple circuit and assembling costs are as low as very few components are used. 

The circuit schematic

The circuit is self-explanatory as no complicated designs are involved. VR1 can be adjusted for the required frequency generation. VR1 and C1 are frequency-determining components. VR2 can be adjusted for tone setting and sound output. 8 ohms speaker delivers the amplified audio output. 

Assembling tips and tricks

The circuit can be easily assembled with a general-purpose PCB or Vero board. Proper metal enclosures to the circuit avoid hum pick-ups and external disturbances. 

To sum up

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