The reason why current can flow in the wire is also because there is a difference between high potential and low potential in the current. This difference is called potential difference, also known as voltage. In other words. In a circuit, the potential difference between any two points is called the voltage of these two points. Voltage is usually represented by the letter v.
Power supply is a device that provides voltage to both ends of electrical appliances. The voltage can be measured with a voltmeter (symbol: V).
The voltage law of series circuit: the total voltage at both ends of series circuit is equal to the sum of the voltages at both ends of each part of the circuit.
Extended data
Commonly used voltage levels in China: 220V, 380V, 6.3kV, 10kV, 35kV, 10kV, 220kV, 330kV, 500kV, 1000kV. Power system is generally composed of power plants, transmission lines, substations, distribution lines and electrical equipment. Voltage lines above 35kV are usually called transmission lines.
Voltage lines of 35kV and below are called distribution lines. The rated voltage above 1kV is called "high voltage", and the rated voltage below 1kV is called "low voltage".
China stipulates that safe voltage is 42V, 36V, 24V, 12V and 6V.
In the AC voltage class, it is usually called low voltage below 1kV, medium voltage above 1kV and below 35kV, high voltage above 35kV and below 220kV, ultra-high voltage above 330kV and below 1000kV.
In the DC voltage class, the voltage below 800 kV is called high voltage, and the voltage above 800 kV is called UHV.
Baidu encyclopedia-voltage