1. Passive network: equivalent resistance
ia +
No RuSiuS
indef ib - Rin
ia S +
No iu
RuS indefib - Rin S?Req?Req?Ro?Ro2. Active network
a
NS b
a
Ro + _ uS ?
b
a
iS Ro b
?
?Thevenin’s Theorem
a N+
s _ uoc
b
?Norton’s Theorema
Ns isc
b
a
a Ro=Req No + b Req
_ us=uoc b
a
a is=isc No b Req
Ro=Req
b
?Thevenin’s Theorem
?Thevennin’s theorem states that a linear two-terminal circuit can be replaced by an equivalent circuit consisting of a voltage source uoc in series with a resistor Req, where uoc is the open-circuit voltage at the
terminals and Req is the input or equivalent resistance at the terminals when the independent sources are turned off. a
a
Ns b
Ro=Req + u=usoc _ b
?Norton’s Theorem
?Norton’s theorem states that a linear two-terminal circuit can be replaced by an equivalent circuit consisting of a current source isc in parallel with a resistor Ro, where isc is the short-circuit current through the terminals and Ro is the input or equivalent resistance at the terminals when the independent sources are turned off.
a
is=isc a
Ns b
Ro=Req
b
CH04-Circuit Theorems - 图文
