The main purpose of making this Voltage Protection Alarm Project is that if a battery is discharged, then we do not know that the battery is discharged, if the battery drops below a fixed voltage, a red led will light up and a buzzer will sound at the same time. This Low/Under Voltage Protection system will work for under-voltage only, it will not work for over-voltage. Through this circuit, we can only monitor the under-voltage of 9 and 12 volt DC batteries.

This Low/Under Voltage Protection Kit is suitable for a 9V and 12V battery, when the battery voltage is normal, it will not alarm. When the battery is over-discharged (less than 10V for 12 volts battery) or (less than 8V for 9 volts battery) in that condition the led will light up and the buzzer will ring along with it. In this, we have used some simple components like LM358 IC, buzzer, led, diode and resistance.