Difference Between AC and DC Current: Know the Definition, Graph & Conversions

Alternating Current (AC) and Direct Current (DC) are two fundamental types of electrical current used in various applications across technology and industry. Understanding the differences between these two forms of electricity is crucial for grasping how electrical systems function and are designed. Direct Current (DC) refers to the flow of electric charge in a unidirectional way. The voltage in a DC circuit remains constant, making it ideal for applications where a stable and constant voltage is required. DC is commonly used in battery-powered electronic devices, such as smartphones and laptops, as well as in automotive applications and DC motors where consistent power delivery is necessary. Alternating Current (AC), on the other hand, involves the flow of electric charge that periodically reverses direction. In an AC circuit, the voltage varies in a sinusoidal manner, which is advantageous for distributing power over long distances, as it can be easily transformed to different voltages using transformers. Most household and office electrical appliances operate on AC because it is the form of electrical energy that utilities supply to consumers due to its efficient transmission capabilities.

The choice between AC and DC depends on the application, with each having specific advantages that make them suitable for different electrical tasks and requirements. Electric current flows in one direction or is constantly changing direction frequently. Therefore, there are two types of current flow; Alternating Current (AC), and Direct Current (DC). The main difference between AC and DC current is the gradual flow of electricity. DC current flows in one direction, while AC current reverses direction periodically.

In this Physics article, we will learn the difference between AC and DC current and see how to convert AC to DC and vice versa.

What is an Alternating Current?

Alternating Current is among the most commonly used and sought-after electric power sources. You can find it in kitchen office buildings, workplaces, and many more. We can recognize it by its waves, also known as a sine wave. These lines are electric cycles, and we count them per second. Therefore, we interpret them by Hertz (or Hz). Given below in the diagram is the sine wave of an alternating current.

Examples of AC Current

The usage of AC is used to power homes and buildings, among others. This is because it is more efficient to manufacture and transport AC over vast distances. Additionally, AC is a power source for electric motors in fridges, washing machines and many others.

What is Direct Current?

In direct current, the current flow does not change frequently. Instead, we’ll see the electricity flowing in a single direction will be at a steady voltage. The use of DC is to supply electricity to electrical devices and charge batteries, as it can only flow in one direction. So it is capable of charging electronic devices like laptop, mobile phones, etc. Given below in the diagram is the straight line of a direct current.

Examples of DC Current

Examples include mobile batteries, flashlights, television sets with flat screens as well as hybrid vehicles, electric vehicles, and so on. This means that everything that is powered by a battery and with an AC adapter when connected to the wall or USB relies on DC.

Difference between AC and DC Current

AC Current	DC Current
The current moves in both directions.	The current moves only in one direction.
Its load can be resistive, capacitive, or inductive.	Its load is only resistive.
Its frequency is between 50-60 Hz.	Its frequency is always zero.
It has a negative as well as a positive polarity.	It has no polarity at all.
The direction of the flow is bidirectional.	The direction of the flow is unidirectional.
Its power factor is between 0 and 1.	Its power factor is always 1.
Its passive parameter is impedance.	Its passive parameter is resistance.
It gets transmitted over long distances and also maintains its electric power.	It does not get transmitted over long distances and also loses its electric power.
It has a rotating magnetism.	It has a steady magnetism.
Its magnitude of current varies over time.	Its magnitude of current remains constant.
Its electron flow goes from forward to backwards and vice versa.	Its electron flow goes only forward.
Its waveform types are sinusoidal, triangular, and square trapezoidal.	Its waveform types are pure and pulsating.
Its source is an AC generator.	Its source is batteries, electrochemical cells, and photovoltaic cells.
It is mainly used in electric motors present in electric appliances.	It is used in mobile phones, television sets, etc.
It is also used in industries, factories as well as in households.	It is also used in electrolysis, electroplating, electronic appliances, etc.

AC to DC Conversion

• Rectifiers: Rectification refers to the process of converting AC supply into DC supply. Rectifiers use devices to convert AC supply into DC supply.
• Rotary Converter: A rotary converter is an inverter, mechanical rectifier or frequency converter. It converts the alternating present (AC) into direct current (DC) through mechanical energy.

• Power supply in switch-mode (SMPS): An SMPS, also known as a switched-mode power supply (SMPS) is an electronic component made up of switches, such as MOSFET which are switched up and down at higher frequencies (in kHz) as well as storage components like capacitors or inductors which serve to provide electricity when the switch is not in a conduction state. The devices are connected by an intricate circuit and are utilized to convert AC into DC.

DC to AC Conversion

This conversion takes place only through the inverters. Inverters are used to power electronic appliances in the event of a power outage. In the same way, it transforms AC to DC to charge the battery and then converts DC to AC to power the electronic device.

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