The direction of alternating current will change with time;

While the DC current does not change periodically.

2. The development history is different.

Alternating current: When electromagnetic induction is discovered, you will know how to generate alternating current. The early products were developed by michael faraday, an Englishman, and Pixar, a Frenchman.

DC: 1882, Edison Electric Lighting Company (founded in 1878) established the first power station in New York State. Three 1 10 volt DC generators were installed. This generator was invented by Edison in 1880. 1500 watt 16 watt incandescent lamp available.

Extended data:

Principle of direct current:

The circuit through which DC current flows is called DC circuit, which is a closed conductive circuit composed of DC power supply and resistor. In DC circuit, a constant electric field is formed. Outside the power supply, positive charge flows from high potential to low potential through resistance. In the power supply, the non-electrostatic force of the power supply is used to overcome the electrostatic force, and then it changes from low potential to high potential, forming a closed current line.

Therefore, in DC circuit, the function of power supply is to provide a constant electromotive force that does not change with time and provide energy for Joule heat consumed by resistance.

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