value of the voltage to the maximum value of voltage is the same

as the ratio of the effective value of current to the maximum

value of current. Stated another way, the effective or rms

value (Eeff) of a sinewave of voltage is 0.707 times the maximum

value of voltage (Emax).

Thus,

Reff √ Average of the sum of the squares of E inst

or, Eeff = √0.707 x Emax

and, Emax = √1.414 x E eff

When an alternating current or voltage value is specified in a

book or on a diagram, the value is an effective value unless

there is a definite statement to the contrary. Remember that

all meters, unless marked to the contrary, are calibrated to

indicate effective values of current and voltage.

Figure 67 shows the relationship between the various values used

to indicate sinewave amplitude. Review the values in the

figure to ensure that you understand what each value indicates.

FIGURE 67. VARIOUS VALUES USED TO INDICATE SINEWAVE AMPLITUDE.