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If the electric current in a circuit travels back and forth, it is called an alternating current. The voltage in alternating current circuits also changes periodically. AC is used to transmit electricity at high voltages over long distances. It is more efficient as energy wastage in the form of heat is lower during this process compared to DC.

Alternating Current Circuits

An electric circuit is a combination of several components connected end-to-end.Alternating Current Circuits or AC circuits are simply circuits powered by an Alternating Source, either current or voltage.

The components mentioned above in a circuit require electrical energy to work. Hence, they cannot increase the power of electrical signals provided to them in the circuit. These components can be arranged in alternating current circuits in several ways, and as long as the circuit is closed, they will work efficiently. 

The current in 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 intervals. Hence, they are called alternating current circuits.

How to Calculate the Frequency of an AC Voltage

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

f = 1/T

Where T = the period, i.e., the length of time calculated in seconds that a waveform needs to repeat from start to end, forming one complete wave.

In terms of w, 

f = w/2π

Calculating the Alternating Current Frequency 

The AC frequency is the number of cycles in an AC sine wave per second. Frequency means the rate at which the current in the circuit changes its direction per second. Frequency is measured in hertz (Hz), and 1 Hz = 1 cycle per second. 1 cycle is a complete wave of an alternating current/voltage. Alternation is used for a half cycle, and a period is the time needed to complete 1 entire cycle or alternating current waveform. 

The equation below is used to calculate the alternating current frequency. 

V (t) = 170 sin (2π60t)

The frequency of AC is 50 to 60Hz, depending on a country’s energy resources. The frequency of the direct current is 0, as it flows in a single direction.

An example of how frequency can be calculated from waveform has been given. An alternating waveform in the diagram above is 3 waves per second, and the frequency of such a waveform will be 3Hz. 

Uses of Alternating Current Circuits 

  • AC is used for the distribution of power. Huge power plants generate electricity, and it is transmitted through wires. 
  • AC is used for long-distance electricity transmission because it ensures lower heat loss, given the wastage due to the high voltage present in the currents. 
  • When the current reaches its destination, its voltage is lowered using transformers. 
  • The outlets that provide the electricity required to run appliances in people’s homes and offices contain alternating power circuits.
  • The batteries contain direct current. But when batteries need to be charged, such as a laptop’s battery, an AC adaptor is used to charge them. This adaptor converts the AC from the outlets to DC for the storage of electricity in the device.
  • AC has also been used to power motors once their battery is used up. For example, electric and hybrid cars need recharging once their battery is exhausted.  
  • AC is less dangerous and easy to operate, making it a favourable property of alternating current. 
  • The loss of energy is lower in AC during electricity transmission, even at high voltage. Hence, it is more efficient.
  • High voltage means low currents are produced, and if the currents are low, the heat produced will also be low. 

Conclusion

When the electric current in a circuit travels back and forth, it is called an alternating current. The voltage in alternating current circuits also changes periodically.Alternating Current Circuits or AC circuits are simply circuits powered by an Alternating Source, either current or voltage. The voltage that can change its magnitude along with its polarity at random time intervals is called an alternating voltage. The AC frequency is the number of cycles in an AC sine wave per second.