ELECTRONIC PRINCIPLES - OD1647 - LESSON 1/TASK 1
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.
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