Explanation:

A mobile phone charger is an electronic device that converts the high voltage AC power supply from the mains to low voltage DC power supply, which is suitable for charging the battery of a mobile phone.

Step-down Transformer:

A transformer is an electronic device that is used to transfer electrical energy from one circuit to another through electromagnetic induction. A step-down transformer is a type of transformer that has fewer turns on the secondary coil than the primary coil. This transformer is used to convert high voltage AC power supply to low voltage AC power supply.

Working of Mobile Phone Charger:

A mobile phone charger consists of a step-down transformer that is used to convert the high voltage AC power supply from the mains to low voltage AC power supply. The low voltage AC power supply is then rectified to DC power supply using a bridge rectifier. The rectified DC power supply is then filtered using a capacitor to remove any AC ripples that may be present. The filtered DC power supply is then regulated using a voltage regulator to provide a constant DC voltage that is suitable for charging the battery of a mobile phone.

Conclusion:

In conclusion, a mobile phone charger is an electronic device that converts the high voltage AC power supply from the mains to low voltage DC power supply, which is suitable for charging the battery of a mobile phone. The step-down transformer is used in a mobile phone charger to convert the high voltage AC power supply from the mains to low voltage AC power supply.