Cell Charger Circuit Question

aman_gupta_009

In a simple cell charger circuit using 1 transformer a diode a resistor a lamp for current indication and a cell how overcharging of cell can be avoided ? someone told me that on full charging of the cell the circuit will become open. how is it possible ?

Thats simple, use a comparator(use an op-amp as a comparator).
lets say ur battery can charge only upto 5 volts.
So, give the non-inverting input pin of the comparator as 5v (as reference voltage) and give the charger output to the inverting input pin to the comparator. When the charger output attains 5 v or goes slightly above it, the output of comparator is zero, making the circuit open!!!!
😉