Direct Current Fundamentals - Electrical Engineering - Report

This report provides a comprehensive overview of Direct Current (DC) fundamentals. It begins with a definition of DC, explaining the unidirectional flow of electrons. The report then details various methods of DC production, including batteries, solar panels, and DC dynamos, along with the conversion from Alternating Current (AC). It highlights the advantages of DC, such as ease of storage and compact device design, while also addressing disadvantages like voltage limitations and transmission difficulties. The report concludes with references to relevant literature, offering a solid foundation for understanding DC concepts and their practical applications in electrical engineering.

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Direct Current

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Definition : According to Thomas Floyd1, ’Direct current is defined as the
unidirectional flow of the electrons in the conducting wires forming a closed loop
from high potential difference to low potential difference. Direction of flow of current
is opposite to the direction of flow of electrons.’
Methods of Production : DC – current can be produced by following methods-
 Battery : Some internal chemical mechanism in the battery produces a potential
difference across its open terminals (emf). When the terminals are closed with a
circuit, we get a direct current.
 Solar Panel : Its works on the principle of Photovoltaic effect. When light falls
on the crystal, direct current is produced and is stored in a battery.
 DC-Dynamo : As stated by Stephen Herman2, it works on the principle of
‘Electromagnetic Induction’ and produces pulsating direct current which can be
filtered using capacitors.
 From Alternating current : An Alternating current can be converted into Direct
Current using Rectifiers and Filters.
Advantages-
 A DC-Current can be stored very easily on a small scale.
 DC current devices are relatively compact and work for years. All the
semiconductor devices uses DC
 There is no Inductive and capacitive losses unlike in AC-current.
Disadvantages-
 It is difficult to generate high voltage DC-current due to commutation problem.
 Voltage cannot be stepped up or stepped down easily.
1 Thomas L Floyd, Electric Circuits Fundamentals (8TH edn, Pearson Education 2009)
2 Stephen L. Herman, Direct Current Fundamentals (8th edn, Cengage Learning 2011)

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 Transmission over large distances is very difficult due to large heat losses.
References-

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1 Floyd T.L., Electric Circuits Fundamentals (8th edn, Pearson Education 2009)
2 Herman S.L., Direct Current Fundamentals (8th edn Cengage Learning 2011)