which is wired as an astable multivibrator here. The piezo buzzer and LED are derived from the ICs pin 3, which is the output pin of the IC. The output of the IC goes high and low continuously due to which the LED and buzzer goes continuously ON and OFF. You can control this ON OFF rate with the 100K variable resistor used in the circuit.
You can operate the circuit with any voltage from 5 to 15 volt DC. If you are using the circuit with the voltage around 6 volts then use a lower value current limiting resistor with LED and change 470 Ohms resistor to 330 Ohms.
Here is a schematic of a beeper circuit. The circuit will generate a continuous beep-beep sound signal with flashing an LED. You can use this simple beeping circuit with any of your electronic project or appliance in which you want the beep-beep sound signal. The circuit is build around a 555 timer IC