In today’s world, we are fully dependent on the use of technology for almost everything. Most of our technology runs on electricity. The electricity in our homes comes in two types – AC & DC. Here is the difference between the two.
Summary
DC Currents vs AC Currents
The main difference between DC (Direct Current) and AC (Alternating Current) is that DC Currents flow consistently in one direction whereas, in AC Currents, the direction of flow of electrons keeps switching back and forth.
In DC Currents, the flow of current is monodirectional – that is, current only flows in one direction and keeps flowing in that particular direction. Hence, the electrons also flow in one direction throughout, that is the direction opposite to the flow of current.
In the case of alternating currents, the direction of flow of current keeps switching. While the net flow of current travels in one direction, the current itself keeps switching its direction from forwards to backwards, and forwards again.
Therefore, the direction of the flow of electrons also keeps switching at regular intervals.
Comparision Table Between DC Currents and AC Currents
| Parameters of Comparison | DC Currents | AC Currents |
| Direction of Flow of Current | DC Currents flow in a single direction steadily. | The direction of flow of the current keeps switching between back and forth at regular intervals |
| Magnetism of Currents | Steady magnetism ensures the flow of current in a single direction. | Rotating Magnets are used in AC Currents that keep changing the direction of the flow of current. |
| Transfer between Long Distances | Transferring DC Currents over long distances often leads to severe energy loss. | AC Currents are safe to travel between long distances and main electric power. |
| Frequency of Current | The frequency of Direct Currents is 0 Hz, that is zero cycles per second. | The frequency of Alternating Currents ranges between 50 to 60 Hz depending on the geographical location. |
| Use in Household Items | DC Current is used for household items such as batteries, flashlights etc. | AC Currents can not be used in household items as there is no net electricity flow and it damages the battery. |
What are DC Currents?
DC – Direct Current is a type of electrical current in which the flow of direction of current is constant throughout.
The major use of direct current can be seen in our households to provide energy to electrical appliances and to charge batteries.
Alternating current cannot be used in household items. The current flowing in the forward direction is cancelled out by the current flowing in the backward direction. Therefore, the net flow of electricity is zero. This also damages the battery.
The frequency of Direct Currents is zero Hertz – that is zero cycles per second as the direction of flow of current is constant throughout.
Thomas Edison is known to be a pioneer when it comes to work and research of the direct current. He proposed a model in which small, local power plants would be installed to power cities.
As there is a high amount of energy loss while transferring direct current over long distances, these plants would have to be located within 1.5km of the end-user.
Direct current is generated through –
a) An AC generator equipped with a device called a Commutator.
b) A device called a rectifier that converts AC to DC
c) Batteries that generate DC through chemical energy.
What are AC Currents?
AC – Alternating current is a type of current in which the direction of flow of current switches back and forth at regular cycles/intervals.
While carrying direct current over long distances, a large amount of energy loss can be seen. Therefore, Alternating Current is used to transfer electricity over long distances. It can even be used to transfer electricity between two cities while losing neglibigle power.
Due to this reason, alternating current is used to power houses and buildings. It also powers electric motors used in washing machines and refrigerators.
The frequency of alternating current varies between 50 to 60 Hertz – that is, 50-60 cycles a second.
The standard frequency of alternating current used in the United States is about 60 Hertz. Whereas in Europe and certain other parts of the world, the frequency remains about 50 Hertz.
Alternating current is generally represented as a sine wave on a graph.
Another advantage of alternating current is that it can easily be converted from lower to higher voltages, or higher to lower voltages using a device called a transformer.
Nikola Tesla is a pioneer in the research of alternating current. Tesla’s work led to the creation of transformers.
Transformers can be used to step up the voltage to several thousand volts to allow for easier transportation. They could also later step down the voltage to allow for household usage.
Alternating current can be generated using a device known as an alternator.
Main Differences Between AC Currents and DC Currents
- The direction of flow of current in direct current remains constant in a single direction For Alternating Current, the direction keeps switching at regular intervals.
- The frequency of direct current is zero Hertz, whereas thw frequency of alternating current is 50-60 Hz.
- Direct current cannot be used to transfer current over long distances as there is significant energy loss. Therefore, alternating current is used for this purpose.
- Alternating current cannot be used in household items as there is no net flow of energy and it damages the battery. Therefore, the use of DC is seen in batteries and household appliances.
- The graphical representation of direct current is a straight line whereas for alternating current, it is a sine wave.
Conclusion
Different kinds of usage of electricity require different types of flow of current – namely Direct Current and Alternating Current. Research over these types of currents over years has made our lives significantly easier.
The appropriate use of each type of current in each situation allows our electrical gadgets to function smoothly.