RC

Lecture Notes RC Filters (P106-107, P102-105), Chapter 4: System Response) (02/06/03)
I. RC Filters
1. Low-Pass Filter
Consider a RC circuit as shown.
Using voltage division, we get
1
1
1 1
C
out in in in
R C
Z j C V V V
Z Z j RC R
j C
ω
ω
ω
= = =
+ + +
V
R
C
in V out V +
-
then,
(1)
1
1
out
in
V
V j RC ω
=
+
The ratio of the output V to the input V is called Transfer Function (TF), a complex number. out in
TF is a very important concept because it describes a system’s (in this case it is a circuit’s)
characteristics – how the sy...