It’s easier to write node voltage equations for some types of circuit than for others. Starting with
the easiest case, we will learn how to write node voltage equations for circuits that consist of:
• Resistors and independent current sources
• Resistors and independent current and voltage sources
• Resistors and independent and dependent voltage and current sources
The mesh current method uses a new type of variable called the mesh current. The “ mesh current
equations” or, more simply, the “ mesh equations,” are a set of simultaneous equations that represent
a given electric circuit. The unknown variables of the mesh current equations are the mesh currents.
After solving the mesh current equations, we determine the values of the element currents and voltages
from the values of the mesh currents.
It’s easier to write mesh current equations for some types of circuit than for others. Starting with
the easiest case, we will learn how to write mesh current equations for circuits that consist of:
• Resistors and independent voltage sources
• Resistors and independent current and voltage sources
• Resistors and independent and dependent voltage and current sources
4.2 NODE VOLTAGE ANALYSIS OF CIRCUITS
WITH CURRENT SOURCES ---------------------------------------------------
Consider the circuit shown in Figure 4.2-1 a. This circuit contains four elements: three resistors and a
current source. The nodes of a circuit are the places where the elements are connected together. The
circuit shown in Figure 4.2-1 a has three nodes. It is customary to draw the elements horizontally or
vertically and to connect these elements by horizontal and vertical lines that represent wires. In other
words, nodes are drawn as points or are drawn using horizontal or vertical lines. Figure 4.2-1 b shows
the same circuit, redrawn so that all three nodes are drawn as points rather than lines. In Figure 4.2-1 b,
the nodes are labeled as node a, node b, and node c.
Analyzing a connected circuit containing n. nodes will require n - 1 KCL equations. One way to
obtain these equations is to apply KCL at each node of the circuit except for one. The node at which