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Electrical Current

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Direct Current (DC)

Direct current (DC)

Direct current is a type of electric current where the direction of circulation of the electric charge flow does not vary. The charge flow occurs through a conductor, such as a metallic wire, but could also be established through a semiconductor, an insulator or even under vacuum, as occurs in a cathode ray tube. In this type of electric current, electric charges always flow in the same direction, being a characteristic feature against alternating current. A disused synonym for direct current is galvanic current.

The first commercial electrical network, developed by Thomas Edison in the late 19th century, used direct current. Today, due to the advantages of alternating current in terms of transformation and transport possibilities, transport and distribution networks use almost exclusively alternating current.

In the case of applications that require direct current, as in the case of the railway that uses the third rail system, the alternating current reaches a substation that uses a rectifier to convert it into direct current.

How is direct current generated?

Continuous current can be generated from alternating current rectifiers and by other sources of electrical energy.

In many cases, the alternate component that occurs during grinding must be reduced by smoothing capacitors or smoothing shocks. There are also various electrical power sources that supply direct current power directly to a connected load.

Some examples of direct current generation are as follows:

  • Photovoltaic Solar Energy. Solar cells generate a direct current thanks to the photovoltaic effect. The photovoltaic effect allows to convert solar radiation into electricity.
  • Electrochemical batteries.
  • Direct current generators.

Conversely, alternating current can be generated from direct current with the help of a power inverter.

What are the uses of direct current?

Direct current is widely used in the household sector. Some examples are the following:  Computers and computers, audio and video devices.

However, there is no direct current from the socket. Rather, each device is supplied individually from a power supply unit, possibly with temporary storage in an accumulator.

In the industrial sector, direct current is  used for  electrolysis  and  electroplating . These applications require direct current, since the   desired electrochemical processes would not  work  with alternating current . Furthermore, direct current is used in part as a  pulling current  .

When it comes to electric power transmission, alternating current has significant advantages over direct current. With the dominance of  converter stations ,  high-voltage direct current transmission is  becoming increasingly important.


Published: March 15, 2017
Last review: March 27, 2020