Charger circuit failure alarm Designed to alert when there is open or disconnected Battery from charger Circuit and also for short circuit. This circuit designed by using two PNP Transistors and a Buzzer. If you need visual indication then you can use LED also as mentioned in the circuit.
Here two Trnaisitors BC557 acts as a switch to connect the Buzzer to bias, When there is open, short or disconnected battery from charging supply.
Components Required (BOM)
Construction & Working
This charger circuit failure Alarm is connected between charger circuit and changing battery. This circuit can be used in <2 Amps charging current environment. DC supply from charger circuit is picked up through J1 connector and then Buzzer, LED connected between DC supply through Q1 transistor.
Base terminal of Q1 is connected between the Q2 transistor collector terminal and R2 Resistor. DC supply to the battery is connected to the J2 through D2 diode and SW1 switch. Here D2 diode used to prevent Reverse Polarity.
Printed Circuit Board (PCB)
Interactive Board Viewer