Biomedical Engineering Reference
In-Depth Information
EXAMPLE PROBLEM 9.25
For the circuit shown in Example Problem 9.22, let
V
þ
¼þ
V
¼
10 V and
10 V. Graph the
output voltage characteristics of the circuit.
Solution
The solution for Example Problem 9.22 is
3
R
1
þ
2
R
2
v
o
¼
V
s
R
2
V
and greater than
V
þ
, as shown in the following
which saturates whenever
v
0
is less than
graph.
v
0
V
+
3R
1
+2R
2
slope is
R
2
V
S
V
−
9.12 TIME-VARYING SIGNALS
) or sinusoidal source of 50 or 60 Hz is common throughout
the world as a power source supplying energy for most equipment and other devices.
While most of this chapter has focused on the transient response, when dealing with sinu-
soidal sources, attention is now focused on the steady-state or forced response. In bioinstru-
mentation, analysis in the steady-state simplifies the design by focusing only on the steady-
state response, which is where the device actually operates. A sinusoidal voltage source is a
time-varying signal given by
An alternating current (
a-c
Þ
where the voltage is defined by angular frequency (o in radians/s), phase angle (f in
radians or degrees), and peak magnitude (
v
s
¼
V
m
cos o
ð
t
þ
f
Þ
ð
9
:
30
V
m
). The period of the sinusoid
T
is related to
frequency
f
(Hz or cycles/s) and angular frequency by
2
P
T
o
¼
2
P
f
¼
ð
9
:
31
Þ
