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Encyclopedia of Electrical Engineering
 realnfo.com
Encyclopedia of Electrical Engineering

# Series DC Circuits

#### What is DC (Direct Current)?

Direct Current (DC) is the constant flow of Electric Charge from high to low Potential. In the history of electrical science, conventional Current was defined as a flow of Positive Charge as shown in the right of Fig.no1. the direction of conventional current in a series dc circuit is such that it leaves the positive terminal of the supply and returns to the negative terminal.
A Direct Electric Current flows only when the Electric Circuit is closed, but it stops completely when the circuit is open.
Fig.no.1: Left: DC Circuit. Right: Conventional Current flow

#### What is DC circuit?

A Direct Current circuit is a circuit that Electric Current flows through in one direction. DC is commonly found in many low-voltage applications, especially where these are powered by Battery. Most electronic circuits require a DC power supply. The circuit that deals with direct current or DC, is referred as DC circuit and the circuit that deals with alternating current or AC, is generally referred as AC Circuit. The components of the electrical DC circuit are mainly resistive, where as components of the AC circuit may be reactive as well as resistive.

#### What are the components of DC Circuit?

Different parts that appear in DC circuits are including power source , path or wire, control, and load as shown in the right of Fig.no.1. DC power sources include batteries, generators, and piezoelectricity. The dc supply is a two-terminal device with two points to be connected. The path of a circuit is made of a conductor, which has low resistance, but other materials with more resistance, such as insulators, semiconductors, and resistors, are often also used in circuits. Switches are used to control current, but many circuits also have safety devices, such as fuses and breakers, to protect the circuit from high current conditions. A Switch is a device for making or breaking an Electric Circuit.
Understanding the purpose of different components is essential for working with DC circuits.