Lecture 12

1.

RLC Circuits
OEk 1115 - Fundamentals of Electronics
Lecture 12

2.

Conversion of Series-Parallel to Parallel
Q is the quality factor of the coil.

3.

Conversion of Series-Parallel to Parallel
Example. Convert the series-parallel circuit to an equivalent parallel form at the
given frequency. Find impedance.

4.

Solution.

5.

Parallel Resonance
The total current is zero, the impedance of the parallel LC circuit is infinitely large.
These ideal resonant conditions are stated as follows:

6.

Parallel Resonance
Example. A resonant circuit in a communication receiver has a 680 uH inductor in
parallel with a 180 pF capacitor.
(a) What is the resonant frequency?
(b) If 2.0 V is across the parallel combination, what is the current in each
component and the total current?

7.

Parallel Resonance
Solution.

8.

RC Circuits
In the series-parallel RC circuit of Figure determine the following:
(a) total impedance (b) total current (c) phase angle

9.

10.

11.

RL Circuits
For the circuit in Figure 54, find V(R) and V(L) for each of the following
frequencies:
(a) 60 Hz (b) 200 Hz

12.

RL Ciruits
What is the impedance for the circuit

13.

RL Circuits
Find the total current and each branch current

14.

RL Circuits
Convert the circuit to an equivalent series form.

15.

RLC Circuits
For the circuit find I(total), V(R), V(L) and V(C).

16.

RLC Circuits
Find X(L), X(C), Z and current at the resonant frequency

17.

Q&A
Any Questions?