Page 108 - Basic Electrical Engineering

The condition for equivalence is checked from the following conditions viz
v should be same and I should also be same.
oc
sc

In Fig. 2.7 (a), V = 20 V.
oc
In Fig. 2.7 (b), V = 4 A × 5 Ω = 20 V.
oc
I in Fig. 2.7 (a), 4 A.
sc
I in Fig. 2.7 (b), 4 A.
sc

This two circuits are equivalent because the open circuit voltage and short

circuit current are the same in both the circuits.

Example 2.2 Convert a current source of 100 A with internal resistance of
10 Ω into an equivalent voltage source.

Solution:

Here I = 100 A, R = 10 Ω
sh

For an equivalent voltage source

V = I × R = 100 × 10 = 1000 V
sh

R = R = 10 Ω in series
sh
se

The open circuit voltage and short circuit current are the same in the two
equivalent circuits as shown in Fig. 2.8 (a) and 2.8 (b), respectively.

Figure 2.8 Conversion of a current source into an equivalent voltage source