Difference Between AC and DC Currents (With Table)

AC vs DC

Some of the questions that we will try to answer here are;

  • What is the key difference between the two currents?
  • Which of the two currents is more powerful?
  • Which of the two currents is more cost-efficient?

When the electrons move from one place to another, then there is a flow of electricity. The direction of the electrons determines the key difference between the two forms of current or electricity.

The key difference between AC and DC currents lies in the fact that the Direct current is steady and unidirectional i.e. the flow of electrons is always in the forward direction.

However, the Alternating current flows in multiple directions i.e. the movement of electrons is first in forward and then in the backward direction.

Also, as s fun fact you should know that Alternating Current is the most viable option for transferring electricity from one point to another.


 

Comparison Table Between AC and DC (in Tabular Form)

Parameter of ComparisonAC CurrentDC Current
DefinitionAn Alternating Current reverses the direction of the flow of electrons while flowing in the electric circuit.The Direct Current is unidirectional with the flow of electrons inside the electrical circuit.
VariantsSquare, Triangular, Circular, Sinusoidal Wave form etc.This is pulsating in nature and pure by form.
Source of GenerationAll the Alternating Current Generators and mains are the key sources of AC currents.All the cells or batteries are the key sources for Direct Current generation.
Electron Movement and DirectionThe electrons keep on changing the direction of flow i.e. forward and backward direction.The electron movement is unidirectional i.e. the flow is only in the forward direction.
Current MagnitudeThe magnitude of Alternating current varies with time.The magnitude of Direct Current does not vary with time.
Power FactorThe Power factor for AC fluctuates between 0 and 1.The Power factor value for direct current is always 1.

 

What is AC or Alternating Current?

An Alternating Current is defined by the flow of electrons inside an electric circuit that changes their directions periodically. It is the source of power for the following industries;

  1. Houses of people and other neighbors.
  2. Offices and Work locations.
  3. Buildings or nearby apartments.
  4. The main source of power for electric motors.
  5. It can be used for voltage control in transformers.

AC could be easily produced with the help of a device called the Alternator that generates the Alternating Currents. To generate it, we need a source of the magnetic field.

Inside the source, a loop of wire will be spun and electrons will start flowing in one direction.

The wire rotation can be generated via any turbine or electric motor as the source. Due to different magnet ports inside the wire, the direction of electrons keeps on changing repeatedly and thus results in 9V AC generation.

Alternating Current
 

What is DC or Direct Current?

A Direct Current is defined by the flow of electrons inside an electric circuit that flows unidirectional i.e. in the forward direction.

This is also governed by the flow of electrons from a negative pole to the positive pole of the magnet.

The major disadvantage of DC is that it is unable to travel to long distances as it begins to lose its energy. Also, the frequency of DC will always be zero (0).

The flow of electrons is always from the area of superior electron density to a zone where the electron density is relatively lower.

To the change, the direction and voltage of DC are relatively expensive and difficult to achieve. This makes it a poor choice for long-distance voltage transmissions.

In today’s world, most of the computer accessories and devices use DC such as any solid-state equipment would consume up to 14 V of DC.

The best real-life example of Direct Current is batteries that are used everywhere nowadays. All the batteries have 2 terminals i.e. positive and negative terminals.

The current will flow between the 2 terminals of the battery and DC will be generated.

Some of the common applications of DC are;

  1. Charging Batteries
  2. Automotive Appliances
  3. Aircraft application and charging
  4. Other Low voltage and low current devices.

Marine DC High Voltage lines are a very feasible option because in subsea environment AC is not the best possible option.

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In such cases, the electricity is first produced in AC form and then transmitted to DC form via different electric cables.

Later at the destination, the current is again converted to AC for regular use. Thus, conversion from AC to DC is relatively cheap and easy but vice versa is a costly deal.

Direct Current

Main Differences Between AC and DC

Although both are methods of electricity or voltage transfer there exist a lot of differences between AC and DC when it comes to the flow and properties of electrons.

  1. AC reverses its direction while flowing while DC always flows steadily and uniformly.
  2. DC is the current that has constant magnitude while AC has a magnitude that varies with time.
  3. The passive parameters for alternating current are Impedance while resistance is the parameter for direct current. 
  4. DC has a power factor value of 1 while for DC the value fluctuates between 0 and 1 respectively.  
  5. The frequency of DC will always be zero. But the frequency of alternating current varies from 50 Hz to 60 Hz.
  6. AC is 2 directional while DC is always unidirectional i.e. the electrons only move from high-density electron side to low-density electron location.

 

Frequently Asked Questions (FAQ) About AC and DC

  1. Why is AC current better than DC current?

    AC current is used over the DC current because in AC current as Goes by the name, the various voltages from high intensity to low intensity can be delivered which cannot be done in DC current.

    Also AC current is cheap to generate and energy losses are also less.

  2. Why DC current is not used in homes?

    DC current is direct current. It is not used in homes because in homes as we have children and people living.

    If some mistake happens, the person will not get a chance to remove his or her hand from that particular thing as there are no fluctuations in the current which are present in the form of AC current.

  3. How is AC converted to DC?

    The direct current is converted into alternating current with the help of a device known as a rectifier.

    The rectifier converts the straight or the direct current into fluctuating alternating current.

  4. Do phone chargers use AC or DC?

    The phone charges use the direct current instead of using the alternating current.

    This is because of the fact that direct current can be stored easily in the batteries, Power Banks or any other such energy storing device.

  5. How do you convert 230v AC to 12v DC?

    In the first step down Transformer is used to lower it down to 30v. The second is to rectify which is done with the help of 4 diodes.

    Then the ripples are filtered out using a filter. Now with the help of LM 317, the output is regulated to 12V.

  6. Are batteries AC or DC?

    All the batteries are only DC or direct current in nature.

    The generate the voltage in only one direction and all also generate polarity of negative and positive.

  7. What happens when you mix AC and DC?

    As such nothing will happen if you mix AC with DC.

    But for using the AC current in DC appliances you have to create the circuit accordingly so as to manage the frequency and the impedance.


 

Infographic

AC vs DC currents


 

Conclusion

It doesn’t matter which of the two currents is better as both have their own set of positives and negatives.

We have learned that AC can be converted easily to DC by using an Adapter or similar tool but vice versa is not easy and this is what makes DC poor choice for long-distance voltage transfer.

But all in all both AC and DC currents are great tools electricity transfer from one location to another.


 

Word Cloud for Difference Between AC and DC

The following is a collection of the most used terms in this article on AC and DC. This should help in recalling related terms as used in this article at a later stage for you.

Word Cloud for AC and DC

 

References

  1. https://energyeducation.ca/encyclopedia/Direct_current
  2. https://whatis.techtarget.com/definition/DC-direct-current
  3. https://www.allaboutcircuits.com/textbook/alternating-current/chpt-1/what-is-alternating-current-ac/