A mobile battery charger circuit is a device that can automatically recharge a mobile phone’s battery when the power in it gets low. Nowadays mobile phones have become an integral part of everyone’s life and hence require frequent charging of battery owing to longer duration usage.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. This simplicity means that a simple charger is inexpensive, but there are tradeoffs. Typically, a carefully designed simple charger takes longer to charge a battery because it is set to use a lower (i.e., safer) charging rate. Even so, many batteries left on a simple charger for too long will be weakened or destroyed due to over-charging. These chargers also vary in that they can supply either a constant voltage or a constant current, to the battery.
aims to automatically disconnect a battery from the mains when the battery gets fully charged. This system can be used to charge partially discharged cells as well. The circuit is simple and consists of AC-DC converter, relay drivers, and charge stations.
In an AC-DC converter section, the transformer step-downs the available AC supply to 9v AC at 75o mA which is rectified by using a full-wave rectifier and then filtered by the capacitor. The 12v DC charging voltage is provided by the regulator and when the switch S1 is pressed, the charger starts working and the power-on LED glows to indicate the charger is ‘on’.