1. The question asks for the working principle of a mobile charger with a proper circuit diagram and waveshape. 2. A mobile charger converts AC mains voltage to a lower DC voltage suitable for charging mobile batteries. 3. The typical circuit includes a step-down transformer, rectifier, filter, and voltage regulator. 4. First, the transformer steps down the high AC voltage (e.g., 230V) to a lower AC voltage (e.g., 12V). 5. The rectifier (usually a bridge rectifier) converts AC to pulsating DC; its output is a full-wave rectified waveform. 6. The filter, commonly a capacitor, smoothens the pulsating DC to a more stable DC voltage. 7. The voltage regulator then maintains a constant DC output voltage suitable for the mobile device. 8. The waveshape changes from sinusoidal AC to a full-wave rectified pulsating DC, which is then smoothed to nearly constant DC. Final answer: A mobile charger works by stepping down AC voltage, rectifying it to DC, filtering to smooth it, and regulating the output DC voltage to safely charge mobile batteries as shown in the circuit stages.