1. The directional movement of electric charge generates electric current, whether it is positive or negative. If the metal or semiconductor device conducts electricity, the atoms will not undergo chemical changes, because the lost electrons will be replaced from other places. But if the high-voltage test transformer conducts ions, then the ions will be ionized at the electrode and attached to the electrode, causing chemical changes.

2. The positive charge will also move. It is convenient to specify the direction of movement of positive charge as the direction of current. For example, when calculating, you can get a negative value by substituting negative charge into the calculation. It can be seen that the direction of current is opposite to the direction of movement of negative charge.

3. The battery provides voltage. Under the power supply voltage, an electric field is generated in the conductor, and the electric charge moves under the action of the electric field to form an electric current. But if the current is to continue, the battery must provide electrons, otherwise the electrons in the wires will run out! But where did the electrons in the wires go? There is no doubt that they will go to the power source. Therefore, the electrons ran out of the power supply and then ran back to the power supply. After the circuit is disconnected, the wire is not charged. It can be seen that the electrons in the wire are not added or subtracted, and the electrons in the battery must be no less. So the battery does not provide electrons and does not consume electrons. The battery only provides voltage.