1. Located inside the mobile phone, the seat charger is on the circuit inside the seat charger
2. See 1, a better limited voltage protection function, the battery will automatically stop charging after full, almost universal charging internal circuit is relatively simple just convert AC to DC and then charge, no limited voltage protection, long time charging will destroy the battery.
3. The one you removed is the transformer, the charging control is integrated in the mobile phone motherboard, and the transformer is only responsible for converting the voltage and output current
4. The charger has a circuit that controls the current output, and the charging is not directly connected to the positive and negative terminals of the battery from the transformer, so the charger is not necessarily equal to the line charging time.
Generally, the official charger is expensive, to one or two hundred, the internal circuit design and workmanship are very good, and the charging time is almost the same as the line charging.
The internal circuit board of the hybrid charger is very poor (I have dismantled the Nokia assembly charger), which is also harmful to the battery, and it is recommended to use the original charger.