This is the circuit diagram of beeper sound. The circuit will generate the sound of a beeper which similar with the one in pagers. It produces a “beep-beep” sound. The work of this circuit is simple, the circuit applied the 555 timer oscillator which is turned ON and OFF periodically.
The first 555 IC (left IC) oscillates at about 1Hz. The second IC (gight IC) is turned ON and OFF by the first IC. The first IC will decide how fast the second IC is turned ON/OFF, while the second IC determines the tone frequency of the output. By adjusting the variable resistor VR1, the changeover rate can be vary. By adjusting VR2 the tone frequency can be altered.