Simple Electronic Horn Circuit using IC 555

Using the well known IC 555, an electronic horn circuit may produce a range of tones for bicycle horns, alarms or even for pranks.

This simple circuit, which is made up of two IC 555 and an 8Ω loud speaker, generates a louder horn sound for cars or alarm systems.

As an astable multivibrator, the circuit makes use of a 555 IC.

This indicates that a square wave oscillation is produced by the constant switching of the output voltage between high and low.

Pitch and loudness are determined by the oscillations frequency and duty cycle, which are essentially its on/off time ratio.

The electrical impulses in the circuit are converted into audible sound waves via a speaker that is linked to the output.

Circuit Working:

Parts List:

The first 555 IC1 chip acts as an oscillator, generating a series of electrical pulses.

These pulses determine the basic rhythm or repetition rate of the sound.

A resistor R3 and a variable resistor VR2 are connected to the first timer chip.

By adjusting the variable resistor VR2, you can change the duration of these pulses, affecting the perceived pitch of the sound.

The second 555 IC2 chip is configured to produce a much higher frequency oscillation.

This high frequency signal is fed directly to the speaker.

In simpler terms, the first IC1 sets the speed pulse duration of the on and off switch, while the second IC2 provides the rapid switching that creates the actual sound waves the speaker can reproduce.

By adjusting the resistors, you control the rhythm and pitch of the resulting sound.

Formulas:

Use the following formulas to create an astable multivibrator circuit for an electronic horn using the IC 555:

Calculating Frequency and Duty Cycle:

The astable multivibratos oscillation frequency (f) may be found using the following formula:

f = 1.44 / ​(R1 + 2 × R2) ×C

• This formula establishes the frequency or tone of the horn sound by calculating the speed at which the 555 oscillates.

The duty cycle, or the ratio of high to low output times, is roughly:

Duty Cycle = R1 + R2​ / R1 + 2 × R2 × 100%

The duration of the outputs high and low states is determined by this formula which has an impact on the horns sound qualities.

You may efficiently create an astable multivibrator circuit utilizing the IC 555 for an electronic horn application by following these calculations and suggestions.

Based on your unique needs for frequency, duty cycle, and sound qualities, change the component values.

How to Build:

To build a Simple Electronic Horn Circuit using IC 555 you need to follow the below mentioned steps for connections:

• Assemble all the components as shown in diagram above.
• Connect pin 1 of IC1 555 to ground.
• Connect pin 2 to pin 6 of IC1 555.
• Connect pin 3 of IC1 555 to pin 7 of IC2 555 through resistor R2
• Connect pin 4 of IC1 555 to positive supply of +9V.
• Connect pin 6 to pin 2 of IC1 555.
• Connect pin 7 of IC1 555 to positive supply through resistor R3.
• Connect pin 8 of IC1 555 to positive supply.
• Connect VR2 preset first leg to pin 7 of IC1 555 and second leg from pin 2 and 6 of IC1 555.
• Connect capacitor C3 from pin 2 and 6 of IC1 555.
• Connect pin 1 of IC2 555 to ground.
• Connect pin 2 to pin 6 of IC2 555.
• Connect pin 3 of IC2 555 to one end 8 ohm speaker through capacitor C1 and other end of speaker to ground.
• Connect pin 4 of IC2 555 to positive supply of +9V.
• Connect pin 6 to pin 2 of IC2 555 through capacitor C2 to ground.
• Connect pin 7 of IC2 555 to positive supply through resistor R1.
• Connect pin 8 of IC2 555 to positive supply.

Conclusion:

To conclude, this article shows how to build a controlled electronic horn circuit using a popular integrated circuit the 555 IC.

The rhythm and pitch of the sound that is produced may be altered by adjusting the timing components resistors, providing a basic and adaptable solution for a range of applications.

References:

Datasheet IC 555