Each cycle of the sine wave shown in figure 61, on the previous

page, consists of two identically shaped variations in voltage.

The variation which occurs during the time the voltage is

positive is called the POSITIVE ALTERNATION. The variation

which occurs during the time the voltage is negative is called

the NEGATIVE ALTERNATION. In a sine wave, these two

alternations are identical in size and shape, but opposite

polarity.

The distance from zero to the maximum value of each alternation

is called the AMPLITUDE. The amplitude of the positive

alternation and the amplitude of the negative alternation are

the same.

h. *Wavelength*. The time it takes for a sine wave to complete

one cycle is defined as the period of the waveform. The

distance traveled by the sine wave during this period is

referred to as WAVELENGTH. The wavelength is the distance along

the waveform from one point to the same point on the next cycle.

You can observe this relationship by examining figure 62. The

point on the waveform where measurement of the wavelength begins

is not important as long as the distance is measured to the same

point on the next cycle (figure 63 on the following page).

FIGURE 62. WAVELENGTH.