Characteristics of Alternating Current (AC)

There are various characteristics of alternating current, some of these are listed as follows:

• Sinusoidal Waveform
• Frequency and Amplitude
• Alternating Current Average Value
• Alternating Current Peak Value
• Alternating Current RMS Value
• Phase and Phase Difference

Let’s discuss these characteristics in detail.

Sinusoidal Waveform

Alternating current has a waveform that varies smoothly and is periodic with time and also looks like a sine wave.

Due to these all features of the waveform, it resembles a sine wave and represents the instantaneous value of the current or voltage over time. The alternating current waveform is called sinusoidal waveform due to its similarity with the sine wave.

Frequency and Amplitude

Frequency of an AC sinusoidal waveform refers to the number of complete cycles it completes per second and is measured in Hertz (Hz). In many power systems, the standard frequency is 50 or 60 Hz. The amplitude of an AC waveform represents the maximum value of the current or voltage reached during each cycle.

Alternating Current Peak Value

The peak value of an AC waveform refers to the maximum positive or negative value reached during each cycle. It represents the highest magnitude of the waveform. Generally, this is represented as I_m or I₀.

Alternating Current Average Value

Compared to DC, AC doesn’t have a constant value, as it oscillates. Thus, we use the average value of AC over a half cycle, as for the complete cycle average value is 0 because positive and negative halves cancel each other out. The mathematical Formula for the average value of AC for a positive half cycle is:

I_av = 2I_m/π

Where,

• I_av is the average value of AC, and
• I_m is the peak value of AC.

Alternating Current Root Mean Square (RMS) Value

RMS value is the value of DC which is flowing through the conductor to produce the same amount of heat as AC is flowing through the same conductor, due to this RMS value is also called the Effective Value of a sinusoidal AC. Mathematically RMS Value of AC is given as

I_rms = I_m/√2

Where,

• I_rms is the RMS value of AC, and
  • I_m is the peak value of AC.

Phase and Phase Difference

In AC systems, multiple waveforms may be present, and they can have a phase difference with respect to each other. The phase refers to the relative position of one waveform compared to another.

Phase difference is usually measured in degrees or radians. The phase difference between two AC waveforms indicates the angular displacement between them. It determines how the waveforms align with each other in time.

Alternating Current and Direct Current are the two types of electricity based on the direction of the voltage and current. In households, we use mostly Alternating Current as the grids are designed to provide alternating current only. But in the case of power storage, DC is used. Alternating currents vary with time so does their voltage.

All the appliances in a common household are wired to work with these types of currents and voltage sources. To understand the workings of these devices in real life, it becomes essential to understand the concepts behind alternating current (AC). Let’s look at these concepts in detail.