Battery charger with alarm application

摘要

Unlike any other battery charger, this project is about the combination of battery charger circuit with alarm circuit. The main objective of this project is the alarm will send signal to the user. Thus, the user will know that the batteries are already fully charged. It consists of 3 segments, the power supply, charging circuit and alarm circuit. In this project, the charging process is focus more on AA batteries. The heart of the circuit located at LM324. It is the segment that controlling the charging process of the whole circuit. 2 pins are required. First pin (pin 12) is for Upper Limit Set, while the second pin (pin 9) is for lower limit set. This both pin sending the signal as a reference value. The upper limit send an information that the batteries is overcharged while the lower limit send the information about batteries deep discharge. Both of them are controlled by a potentiometer. When this is happen, the LM324 will send signal to the transistor. This transistor than operates thus energizes the relay coil. When the relay retracted, the charging process is halt and at the same time, operates the buzzer. The buzzer will continue to ring until the charger is turn off.