1-12
How the Ideal Series-LC Circuit Respond to a Frequency Below Resonance (100 kHz)
Given:
First, note that XL and XC are no longer equal. XC is larger than it was at resonance; XL is smaller. By
applying the formulas you have learned, you know that a lower frequency produces a higher capacitive
reactance and a lower inductive reactance. The reactances subtract but do not cancel (X
L
-
XC = 1260
-
5300 = 4040 ohms (capacitive)). At an input frequency of 100 kHz, the circuit (still resonant to 205 kHz)
has a net reactance of 4040 ohms. In our theoretically perfect circuit, the total opposition (Z) is equal to
X, or 4040 ohms.
As before, let's apply Ohm's law to the new conditions.
The voltage drops across the reactances are as follows:
