AC1 Fundamentals Unit 8 – Time Constants
UNIT 8 – TIME CONSTANTS
UNIT OBJECTIVE
At the completion of this unit, you will be able to describe the effects of time constants on ac and
dc circuits by using calculated and measured values.
UNIT FUNDAMENTALS
In this unit, we will use square waves when applying ac to a circuit. The square wave shown has
a period of 10 ms, which results in a fundamental frequency of 100 Hz (frequency = 1/period).
Exact multiples of the fundamental (first) frequency are called the harmonic frequencies. For
example, the first harmonic frequency of the 100 Hz square wave is:
100 Hz x 1 = 100 Hz
(first harmonic)
This first harmonic frequency is the fundamental frequency.
The second and third harmonic frequencies are:
100 Hz x 2 = 200 Hz
(second harmonic)
100 Hz x 3 = 300 Hz
(third harmonic)