Download EE 101 Lab 2 Ohm`s and Kirchhoff`s Circuit Laws

EE 101
Lab #4
Fall 2010
Date:
Lab Section #:
Name:
Verify Circuit Analysis
Partner:
Please Circle One: Monday Lecture Tuesday Lecture
Abstract
We have seen that electrical circuits can be described with mathematical expressions, and it is possible to
calculate the currents and voltages of a circuit by solving a set of equations. In resistor circuits, equations
can be determined using Ohm’s Law, which gives the relationship between voltage and current in a
resistor (V=IR), and Kirchhoff’s Current and Voltage Laws, which govern the currents entering and
exiting a circuit node and the sum of voltages around a circuit loop, respectively. By rearranging voltage
loop equations when resistors are in series, we developed the voltage-divider equation. By rewriting
voltage and current equations for resistors in parallel, we developed the current-divider equation.
After completing this experiment you should:
(1) Be able to use circuit analysis tools to calculate the currents flowing through each resistor and the
voltage drop across each resistor of a given circuit.
(2) Be able to construct the resistor circuit on your prototype board and to apply power to your circuit
using the bench power supply.
(3) Be able to use the DMM to measure voltage and current at various parts of a given circuit.
(4) Be able to check the accuracy of your circuit analysis by comparing your analysis results to DMM
measurements.
Introduction
Because today’s lab allows students to practice using concepts covered in previous lectures and labs, and
because there are many ways to analyze circuits, students are encouraged to analyze today’s lab circuit
using many or all of the following analysis “tools”
1.
2.
3.
4.
5.
6.
7.
Ohm’s Law
Kirchhoff’s Voltage Law
Kirchhoff’s Current Law
Equivalent resistors in series
Equivalent resistors in parallel
Voltage divider equation
Current divider equation
Experiment
P1. For each of the seven circuit analysis tools listed above, describe what the tool is and how it can be
used to analyze a circuit. Note: not all tools can be applied to every circuit but no circuit law can ever be
violated.
1. Ohm’s Law
Rev. 9/29/2008
2-2
2. Kirchhoff’s Voltage Law
3. Kirchhoff’s Current Law
4. Equivalent resistors in series
5. Equivalent resistors in parallel
6. Voltage divider equation
7. Current divider equation
2-3
R1
i2
R2
i1
A
R3
12V
i3
i4
R4
i5
R5
0
Figure 1
P2. Analyze the circuit shown in Figure 1. Calculate the currents flowing through each resistor and the
voltage drop across each resistor in the circuit. Find expressions for the source current i 2 and the node
voltage at node A.
2-4
P3. Pick five resistors from the EE101 lab kit. Calculate the current and voltage values you expect to
measure once you build and energize the circuit.
2-5
P4. → Using your prototype board, construct the circuit shown in Figure 1
→ Measure all currents and voltages.
→ Compare calculated and measured values by determining the percent deviation for each. Create a table
to display your test results.