A battery charger or recharger is a device used to put energy into a secondary cell or rechargable battery by forcing an electric current through it.In fact they are used to charge the batteries inside the mobiles by providing them a low level DC voltage and current.There may be different types of chargers used to charge different mobile phones but the key functioning of those all are almost same.A simple charger works by supplying a constant DC or pulsed DC power source to a battery being charged.A simple charger typically does not alter its output based on charging time or the charge on the battery.The mobile chargers are utility item which are used to charge our mobile phones.