ACTIVE NETWORKS:
Active
elements are the sources of energy it may be a current source(or)voltage source
which supplies energy to the circuit.
These are
classified as i) Ideal voltage source.
ii)Practical voltage source.
iii)Ideal current source.
iv)Practical current source.
i)IDEAL
VOLTAGE SOURCE: Ideal voltage source is defined as the energy
source which gives constant voltage across its terminals irrespective of the
current drawn through its terminals. The symbol for ideal voltage source is
shown in figure(a). This connected to the as shown in the figure(b)The value
of voltage at load terminal remains same. This is identically Volt-Ampere
characteristics.
Volt-Ampere characteristics:
PRACTICAL VOLTAGE SOURCE:
In practically voltage source as small internal resistance shown in
series in voltage source as represented by "Rse" as shown in figure.
Vs =Vse + VL
VL = Vs - Vse
VL = Vs - iRse
IDEAL CURRENT SOURCE:
Ideal current
source which gives constant current at its terminals irrespective of the voltage appearing across its
terminals. The symbol for "Ideal current source" is shown in
figure(a),this is connected to the as shown in figure(b) at any time the value
of the current flowing through the load is same this explained by the v-I
characteristics as shown in figure(c)
PRACTICAL CURRENT SOURCE:
But
practically every current source has high internal resistance shown in parallel
with current source and is represented by Rsh .This is shown in figure.
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