Sinusoidal Waveform Terminology - AC Circuits
AC Circuits - Sinusoidal Waveform Terminology:
The amplitude of sine wave is the maximum value (V/I) reached during a positive or negative alternation.
It denotes the maximum value of the alternative quantity reached during a positive or negative direction.
It is denoted as Vm , Im
The value of voltage or current at a particular instant (time) is known as instantaneous value.
Generally it is denoted by small alphabet(v for voltage and i for current).
One complete set of positive and negative values of an alternating quantity is called cycle.
ie during one cycle the wave from trace 0 to +max to 0 to -max to 0.
The time taken for one cycle is known as time period or periodic time.(T).
Its unit is time in seconds
No of cycles made in one second is called as frequency of the alternating quantity.
It is denoted by f.
The unit is Hertz or cycles/second
The maximum value of an alternating quantity (It may be a current or voltage) during a cycle is called its peak value.
A quantity which has only magnitude but no direction ( ex. Resistance)
A quantity which has both direction and magnitude (ex. Force)
The development of an AC quantity through different stages as known as phase.
When two alternating quantities reach their maximum and minimum simultaneously, then these quantities are called as in-phase.
Out of Phase:
When two alternating quantities do not attain their maximum and minimum values simultaneously then they are at out of phase. It is also known as Phase difference.
It is an angular displacement between two alternating quantities.
The arithmetical average of all the values of an alternating quantity over one cycle is called as average value.
For sine waveform the average value is
IAvg = (2/π)Im = 0.637Im
Root Mean Square (RMS) Value:
The rms value of an alternating current is defined as that steady current which when flowing through a given resistance for a given time produces the same amount of heat as produced by the alternating current when flowing through the same resistance for the same time.
For sine waveform the root mean square(RMS) value is
VRMS =(1√2)* Vm = 0.707Vm
IRMS =(1√2)* Im = 0.707Im
It is defined as the ratio of the peak or maximum value, to the r.m.s. value, of a waveform.
For sine waveform = Vm /0.707Vm = 1/0.707 = 1.414
It is defined as the ratio of the r.m.s. value to the average value.
Form Factor = RMS value / Average Value
For sine waveform = 0.707 / 0.637 = 1.11
Thanks for reading about basic terminology of sine wave...
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