A mobile phone charger is
- AAn inverter
- BA UPS
- CA step up transformer
- DA step down transformer
Show answer and explanation
Correct answer: (d) A step down transformer
Explanation
A mobile charger uses a step-down transformer to reduce the mains 220 V AC to a working output of about 5 V.
In a step-down type the secondary coil has fewer turns than the primary, so output voltage is lower than input.
A step-up transformer raises voltage, while an inverter/UPS converts or backs up power, so they do not fit.