The general definition of alternating current is that it is a type of electric current in which, at regular and random intervals, the direction of flow of electrons changes back and forth. This means that the polarities of the current keep on changing with time.

In other words, we can say that the current changes its polarity from positive to negative, with the magnitude in a periodic cycle. The loss of energy is less in Alternating Currents, while the transmission of electricity is even more efficient.

Alternating Currents are used in power stations because less energy is lost when they are used. The current in the alternating-current circuits travels as sinusoidal waves. A complete wave is half positive and half negative. The direction and magnitude of the current can be changed at regular time intervals. This is why they are called alternating-current circuits.

The voltage that can change its magnitude along with its polarity at random time intervals is known as an alternating voltage. The symbol f  is for the frequency of voltage. The general equation to find f  is:

Properties Of Alternating Current 

• AC is more efficient when compared to DC (direct current).
• The ability to change polarities makes it possible for current to travel over long distances. Hence, it can supply power to many places. 
• It is considered easier to operate and handle.
• It is more efficient than Direct Current.
• AC is flexible and can be easily converted from high voltage to low and vice versa. This process is done using transformers. 

How Are Alternating Current (AC) Produced

1. A loop/coil of wire is spun at a fast rate inside a magnetic field in an alternator.
2. Due to this, an electric current is produced along the length of the wire.
3. The spinning of the wire causes it to enter a different magnetic polarity at regular intervals. 
4. As the polarity changes, the voltage and current alternate on the wire as well.
5. The voltage in an AC circuit reverses due to the change in the direction of the current. 

Applications of Alternating Currents

The main applications of Alternating Currents include their use in industries for the transportation of energy from one form to another and for the production of electricity. At present, almost every household has a supply of AC in them. We do not use DC because DC consumes a high level of power when compared to AC, which increases the risk of fire and produces high costs.

AC is also used in giving power to motors in industries. They are the machines that are used to convert electric energy to mechanical energy. There are many machines that use the concept of Alternating Current in our house, like dishwashers, washing machines, etc.

Advantages of Alternating Currents 

1. The generation and transportation of AC at longer distances are easy.
2. In power stations, less energy is lost while transmission at high voltages.
3. During energy/electricity transmissions, the heat produced is lesser due to the low resistance levels. 
4. In hotels/resorts, with the aid of transformers, AC currents can be converted from high voltages to low voltages easily.
5. In cars, motors convert electrical energy to mechanical energy. 
6. Different types of motors are also used in washing machines, dishwashers, air conditioners and refrigerators that make use of AC. 
7. It helps in increasing and decreasing the voltage or current in transformers. 

Conclusion

Alternating current (AC) can be defined as an electric current that reverses its direction at regular intervals, as against a direct current that flows in one direction only. Many electromechanical generators produce electricity by one of the properties of alternating current, which is switching between the positive and negative polarity of voltages in the AC.

The principle of AC generators is electromagnetic induction. It converts the mechanical energy to electrical energy, which is used by the customers. With the help of transformers, AC currents can be converted from high voltages to low voltages easily. Alternating currents thus have many uses in our daily lives.