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Alternating Current changes its direction. Thus, it differs from Direct Current, which flows in a single direction. When variation of Alternating Current is represented with respect to time, it is called Alternating Current Waveform. This waveform helps us to understand the properties of Alternating Current. It also helps us determine the average and root-mean-square values, as calculating a constant value for Alternating Current is impossible.
Alternating Current Waveform Meaning
Due to changing direction of electron flow, the Alternating Current Waveform is present on both the positive and negative sides of the y-axis in the XY graph if the current is denoted on the y-axis and time on the x-axis. This is in contrast with Direct Current. Graphical representation of Direct Current is present only on one side of the y-axis, either positive or negative.
Alternating Current Waveform Examples
Sinusoidal Waveform
Typically Alternating Current Waveform is of a sinusoidal pattern. In the sinusoidal waveform, the current increases in magnitude from zero value to reaching a peak value then decreases in magnitude until it attains zero value. Then the current changes its direction and repeats the process as mentioned earlier.
This sinusoidal Alternating Current Waveform meaning can be understood through the process of generation of Alternating Current by an AC generator. In the AC generator, the voltage is produced through the magnetic flux change of a coil, based on Faraday’s law of Electromagnetic induction. The rate of magnetic flux change follows the sine function. Thus, the resultant voltage and current also follow the sinusoidal pattern.
Terms related to Sinusoidal Alternating Current Waveforms
CYCLE – refers to one complete set of positive and negative values of a waveform. One cycle of a sinusoidal waveform includes one positive half cycle and one negative half cycle.
PERIOD (T) – refers to the time required to complete one cycle. The period of a sine wave can be measured between any two corresponding points on the waveform. It is generally measured in seconds (s).
FREQUENCY (f) – refers to the number of cycles completed in one second. The frequency is inversely related to the period. It is measured in Hertz (Hz).
ANGULAR FREQUENCY (ω) – refers to the frequency expressed in electrical radians/second. As one cycle of a sinusoidal waveform spans 2π radians, the angular frequency is denoted by ω = 2πf, where f is the frequency of the sinusoidal wave.
AMPLITUDE – refers to the peak height of a waveform.
Other Alternating Current Waveforms
Other Alternating Current Waveforms examples are square waveform, triangular waveform, and saw-tooth waveform. Their characteristic shapes are based on their particular generation methods.
The square waveform is mainly used to represent circuit outputs and clock signals. This waveform is symmetrical, similar to a sinusoidal waveform. The symmetrical waveforms have equal durations on the positive and negative sides of the y-axis. This waveform has a flat top at the peak current level. Due to its symmetrical nature, the time taken in completing the positive half cycle is equal to the time taken in completing the negative half cycle. A simple circuit can generate this waveform.
The triangular waveform has a sharper peak edge compared to the sinusoidal waveform. But it has a slower rise and decline than a sinusoidal wave. It is also symmetrical, with equal time duration for the positive and the negative half cycle.
In the saw-tooth waveform, the peaks of the waveform look like the teeth of a hack-saw blade. This waveform can be of two types — positive ramp saw-tooth waveform and negative ramp saw-tooth waveform. The positive ramp saw-tooth waveform has slow rise and steep decay. On the other hand, the negative ramp saw-tooth waveform has a steep incline and slow decline. The positive ramp saw-tooth waveform is most commonly used. Musicians in representing high clarity sound also use this waveform.
In rare instances, Alternating Current Waveform may have a complex pattern. In that case, calculating the average or root-mean-square value is complicated.
Conclusion
Understanding the meaning and examples of the Alternating Current Waveform is required to progress further in learning about the Alternating Current. It is also helpful in proving theorems and solving numerical problems related to Alternating Current. Furthermore, it also broadens our understanding of everyday phenomena such as the flickering of tube lights. It also helps us in distinguishing Alternate Current from Direct Current more clearly.
