Biomedical Engineering Reference
In-Depth Information
A
A
R
EQ
Independent and
Dependent
Sources, and
Resistances
Replaced by
V
OC
B
B
FIGURE 9.22
A general circuit consisting of independent and dependent sources can be replaced by a voltage
source (V
oc
) in series with a resistor (R
EQ
).
equivalent to the original circuit in that the same voltage and current are observed across
any load. Usually the load is not included in the simplification because it is important for
other analysis, such as maximum power expended by the load. Although we focus here
on sources and resistors, this theorem can be extended to any circuit composed of linear
elements with two terminals.
Th
ยด
venin's Theorem states that an equivalent circuit consisting of an ideal voltage
source,
, can be used to replace any circuit
that consists of independent and dependent voltage and current sources and resistors.
V
OC
, in series with an equivalent resistance,
R
EQ
V
OC
is equal to the open circuit voltage across terminals A,B, as shown in Figure 9.23, and
calculated using standard techniques such as the node-voltage method.
The resistor R
EQ
is the resistance seen across the terminals A,B when all sources are
.
Recall that a dead voltage source is a short circuit, and a dead current source is an open
circuit.
dead
A
+
Independent and
Dependent
Sources, and
Resistances
V
OC
-
B
FIGURE 9.23
The open circuit voltage,
V
oc
, is calculated across the terminals A,B using standard techniques
such as the node-voltage method.
