AC1 Fundamentals Unit 8 – Time Constants
Harmonic frequencies that are even multiples of the fundamental frequency (second, fourth,
sixth, etc.) are even harmonics.
The 100 Hz square wave is actually a composite waveform made up of many sine waves. These
sine waves consist of odd harmonic frequencies of the square wave fundamental frequency.
NEW TERMS AND WORDS
fundamental frequency - the principal component of a wave; the component with the lowest
frequency or greatest amplitude. For example, the fundamental frequency of a 100 Hz square
wave is 100 Hz.
harmonic frequencies - sinusoidal waves having frequencies that are integral (positive whole
number) multiples of the fundamental frequency. For example, a wave with twice the frequency
of the fundamental is called the second harmonic.
even harmonics - harmonic frequencies that are even multiples of the fundamental frequency.
For example, 200 Hz and 400 Hz waves are even harmonics of a 100 Hz wave.
odd harmonics - harmonic frequencies that are odd multiples of the fundamental frequency. For
example, 300 Hz and 500 Hz waves are odd harmonics of a 100 Hz wave.
time constant - time required for voltage or current to rise or fall by 63 percent. It results from
the ability of inductance (L) and capacitance (C) to store energy.
EQUIPMENT REQUIRED
F.A.C.E.T. base unit
AC 1 FUNDAMENTALS circuit board
Multimeter
Oscilloscope, dual trace
Generator, sine wave