PHYS345 Electricity and Electronics
Quiz 2 Solution: dc Circuit Analysis
What is the voltage across the current source?
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...
Last updated Sept. 21, 1999.
Copyright George Watson, Univ. of Delaware, 1999.