In this article, we will discuss direct current DC, direct current electricity, sources of DC, applications, properties, and uses of DC. We will also discuss the advantages or benefits of DC. Also, the disadvantages, limitations, or drawbacks of direct current DC will be discussed.
After reading this
article you will be able to answer what is direct current DC, where
is dc used, and some other questions related to direct current.
Definitions
·
Direct Current (DC) is the constant
flow of Electrons from higher to lower Potential.
·
The current that flows only in one direction is called DC.
·
It is the one-directional flow of electric charge.
·
DC or direct current is the unidirectional flow or movement of
electrons.
·
It is the current that does not change its direction
periodically and flows in a single direction.
What is
DC or Direct current?
In DC circuits, the current is in one direction and its frequency is zero, whereas the alternating current (AC) reverses its direction 50 or 60 times a second depending on the frequency of the supply. As the direct current flows, the electrons flow from the lower potential to the higher potential. In a DC circuit, electrons emerge from the negative, or minus, pole and flow towards the positive, or plus, pole. However, the old theory of DC is from positive to negative pole or terminal of supply, which is called conventional current.
The waveform of Direct Current is,
.jpg "Direct Current Waveform")
The intensity of the current can
vary with time, but the general direction of movement of the current remains
the same at all times. The term DC is concerned with the voltage whose polarity never
reverses.
Direct
current is a type of electric current that travels only in one direction.
Direct current means when current
flows continuously in one direction. Direct current is generated by rectifiers,
batteries, generators with commutators, and fuel cells. For example, the
current flowing in a battery-powered device or flashlight is a direct current.
The most common use and necessity of direct current are in electroplating. For
typical commercial electricity, direct current is replaced by alternating
current (AC).
Direct current is defined by the
constant flow of electrons from regions of high electron density to regions of
low electron density (see Figure 1). In a circuit with a battery, this can be
illustrated by a constant flow of charge from the negative battery terminal to
the positive battery terminal. Changing voltage from DC is much more expensive
and difficult than AC, making it a poor choice for high-voltage transmission.
However, over long distances, HVDC transmission may be more efficient than AC.
A DC circuit is a circuit composed
of any combination of a constant voltage source, a constant current source, and
a resistor. In this case, the circuit voltage and current are independent of
time. A particular circuit voltage or current is not dependent on any past
value of the circuit voltage or current. This means that the system of
equations representing a DC circuit does not involve any integration or
derivative to time.
Sources
of DC
·
DC generators
·
Batteries
·
Power converters that
rectify the AC to DC
·
Solar panels
·
Thermocouples
Advantages
of DC
· The most important advantage or benefit of DC is that it can be stored for some time
·
Mostly used in low
voltage so there is a low risk of shock hazard
·
It is more efficient
in short-range
·
It is safer so mostly
used in small and large devices and equipment
·
There is the absence of
many losses, those are present in AC
·
DC is mostly used in
such places where high mechanical power is required
·
There is no issue of
power factor in the DC
Disadvantages
of DC
·
The biggest
disadvantage, drawback, or limitation of DC is that its voltage level cannot be stepped up or stepped down through voltage transformers
·
It becomes very
expensive when its voltage level is increased or decreased
·
It is very expensive
when dealing with high-current systems; i.e., larger cables, fuses, switches, and other components required for high-current, low-voltage applications
·
There is a risk of
fire hazards when maximum circuit ratings and wire sizes are not strictly
adhered to
Applications
of DC
Direct current is used
in almost all electronic equipment, electric vehicles, automotive, control of
electrical equipment, and more. DC power is used to function in office and
domestic equipment such as TVs, audio systems, amplifiers, flashlights,
computers, tablets, and smartphones. DC is widely used in all aspects of life,
from a small emergency torch or hand watch to a large locomotive in the industry that uses
DC to operate. As the universally available power is AC, most of the equipment
uses an external or internal power supply to convert the utility mains AC into
the desired DC for the equipment.
Solar Panels: Mainly,
solar panels produce direct current. It is then used as a DC directly using a charge controller to charge batteries in a solar system. However, when used with an AC main to
supply local AC power, an inverter is used which converts the direct current to
alternating current to enable the direct current supplied by the solar panels.
DC currents are best for powering electronic devices, such as computers and cell
phones.
Direct current is used in almost all
electronic equipment, electric vehicles, automation, electrical equipment
control, etc. Most office and home appliances, such as TVs, sound systems,
amplifiers, flashlights, computers, tablets, and smartphones run on direct
current. However, since the commonly available energy source is alternating current, the device uses an external or internal power source to convert the
alternating current from the utility grid to the direct current required by the
device.
DC power is more consistent in terms
of the voltage supply, which means most electronic devices rely on it and use DC
power sources like batteries. Electronic devices can also convert AC power from
a wall outlet to DC power using a rectifier, usually built into the power
supply of the device.
Direct current is primarily useful
in situations where devices need to store electricity in batteries for future
use. Smartphones, laptops, portable generators, flashlights, outdoor CCTV
camera systems… you name it, anything battery-powered relies on DC power
storage. When the battery is charged from the grid, the alternating current is
converted to direct current by a rectifier and stored in the battery.
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