PHYS345 Electricity and Electronics

Quiz 2 Solution: dc Circuit Analysis

What is the voltage across the current source?

Problem 3-16 via nodal analysis

Via nodal analysis:

Defining the nodal voltages in the conventional way (with the reference node at the bottom grounded to 0 V) leads to:

KCL at node 1:
(V1-2)/2 + V1/3 + (V1-V2) = 0
KCL at node 2:
(V2-V1) + V2/5 -2 = 0

Multiplying eqn. 1 through by 6, eqn. 2 through by 5, and consolidating terms leads to the following two equations to solve:
11 V1 - 6 V2 = 6
-5 V1 + 6 V2 = 10

Adding the two equations produces:
V1 = 2.67 V

Backsubstitution yields the desired answer:
V2 = 3.89 V

For this circuit, for the quantity of interest, nodal analysis is a bit quicker than mesh analysis...


"http://www.physics.udel.edu/~watson/phys345/quiz/02soln2.html"
Last updated Sept. 21, 1999.
Copyright George Watson, Univ. of Delaware, 1999.