Author – Arpita Kashyap


A machine gun is a fully automatic mounted or a portable firearm   to fire bullets in quick succession from magazine, typically at a rate of 300 to 1800 rounds per minutes. Here the main aim of project to produce the sound just similar to machine gun. When there is triggering it will produce sound just in a way like machine gun.

Block diagram of Machine Gun

When power supply is switched on. PNP Transistor will start work, and power supply will reach to pin no 8 or pin 4 of 555 Timer IC through transistor. Then through bypass capacitors, sound waves of same frequency passed and sound will be produced on speaker.

Components used

  1. Capacitor -10µF (C1,C2,C3,C4)
  2. Capacitor-100µF (C5)
  3. 555 Timer IC
  4. Resistors- 100K, 33K (R1,R2)
  5. PNP Transistor – BC557(Q1)
  6. Speaker

Circuit diagram Description of Machine Gun

In below circuit diagram, 555 timer is used. Battery of 6V is connected to speaker as well as PNP transistor BC557. Supply of 6V is given to pin no 8 and pin no 4 of 555 timer IC which are internally connected to each other. Here 555 timer IC work in astable mode. At pin no 5 and pin no 2 , capacitor of 10µF is attached.  3 electrolyte capacitors are also used of 10µF. Two resistors are used of 100K and 33K. In which one resistor is attached between transistor and pin no 1 while other is connected between pin no 2 and output pin no 3.  The one end of speaker is connected to capacitor C4 while other end is connected to capacitor C5.

Circuit Diagram of Machine Gun


When the power supply is on, the circuit start working, means transistor will start work but since it is PNP transistor it will work only when it gain low pulses. When it gain low pulses, the supply is reached to pin 8 of 555 timer IC which work in astable mode. Capacitor C5 act as bypass capacitor which allows only the same frequency sound which leads to produce a sound on speaker. The sound produce on speaker is just like the sound produced by the machine gun.


Machine guns are commonly mounted in one of four ways.

  1. Bipod – common in light machine guns and some medium machine guns.
  2. Tripod – common in heavy machine guns.