A sine wave represents graphically the voltage of the electric current, where we can represent both the voltage of the electric current in direct current, and in alternating current.
The waveform
The alternating current is generated by different methods. The most used are the rotary mechanics, or alternators of the electric coils.
The most common waveforms are:
- the senoidal,
- the square,
- the triangular,
- the sawtooth
All are presented in different types very varied.
Properties of a sine wave
1 Statement
A disturbance along a string is described by the equation
with x and y measured in centimeters and t in seconds.
For this wave, find its amplitude, angular frequency, period, wave number, wavelength and velocity of propagation.
2 Solution
This function is a traveling wave corresponding to the general form
that, by itself of the form f ( x – v t ) is clearly a solution of the wave equation.
2.1 Amplitude
The amplitude of this wave, A, is the coefficient that multiplies the cosine. In our case
2.2 Angular frequency
The angular frequency, ω , is the coefficient that precedes the time in the cosine argument
2.3 Period
From the angular frequency we have the natural frequency and the period
2.4 Wave number
The wave number is the amount that multiplies x in the cosine argument
2.5 Wavelength
We calculate the wavelength from the wave number
2.6 Speed of propagation
The speed of advance of the wave is equal to
Summing up we can say that a sine wave of alternating electric current is bidirectional with respect to time (with positive and negative values) and the mathematical sinusoid that normally draws can be expressed as:
A ( t ) = Am a x⋅ s i n ( 2 π⋅ f⋅ t )
