Electrical LAB assinment that need Lab view including MyDAQ..

UNIVERSITY OF NORTH DAKOTA College of Engineering and Mines

ENGR 206: Fundamental of Electrical Engineering Laboratory #2

Analysis of Simple Resistive Circuits

Introduction

Now you get to repeat all the pre-lab experiments in the “real world.” Unfortunately, circuits analyzed on breadboards do not behave quite as well as their simplified models. However, for most of the experiments that you will do in electric circuits you should find a close correlation.

Solderless Breadboard Figure 1 shows a breadboard and its internal connections. Most of you have been using this component to build simple electric circuits used in EE101 and EE201L. The breadboard that is included in the myDAQ kit will work the same way.

Figure 1: Internal Connection of a Breadboard

Figure 2 show how to identify a resistor based on its color codes.

Figure 2. Resistor Color Code

Now you get to repeat all of the pre-lab experiments in the “real world.” Unfortunately, circuits analyzed on breadboards do not behave quite as well as their simplified models. However, for most of the experiments that you will do in electric circuits you should find a close correlation.

2

Procedure

The circuit shown in Figure 1 can be viewed as a voltage divider between R1 and R2 in parallel with RL. We will first analyze the no-load circuit, in which the load resistance RL is disconnected from the circuit. Let vs = 10 volts, R1 = 10 kW, and R2 = 1 kW. Measure the value of the no-load output voltage vo using the multimeter. Repeat this procedure using values of R2 = 10 kW and R2 = 100 kW. Make sure that you measure the experimental resistance values, and that you record all resistance and voltage measurements.

Figure 1: Voltage Divider Circuit

Next, we will analyze the voltage divider circuit connected to a voltmeter simulated as a finite load resistance. For this experiment, let vs = 10 volts, R1 = 10 kW, and R2 = 10 kW. Connect load resistances of RL = 2.2 kW, RL = 10 kW, and RL = 1 MW to the voltage divider circuit, and measure the output voltage vo in each instance. Describe the effect that you observe for increasing meter-load resistance values. How does this relate to the theoretical voltage divider connected to a load resistance?

A current divider circuit is shown in Figure 2 below. Note that the independent current source has been replaced by a voltage source in series with a 1 kW resistor for this experiment. Using an input voltage of vs = 10 volts and resistor values of R1 = 10 kW and R2 = 100 kW, measure the currents is, i1, and i2 using the multimeter. Is Kirchhoff’s current law satisfied experimentally? Verify that the current division relationships hold. Experimentally compute the power either generated or absorbed by every circuit element, and verify that the total power generated by the source is equal to the total power dissipated by the resistances.

Figure 2: Current Divider Circuit

The intent of the final experiment is to measure the equivalent resistance of a network consisting of

series- and parallel-connected resistances. Measure each resistor within the network below independently using the multimeter. Next, construct the circuit to the right of terminals a-b, and measure the equivalent

R2vs

R1

RLvo

1 kW

R1 R2vs

is i1 i2

3

resistance Rab across those terminals. Finally, connect the voltage source to the circuit and measure the

current i generated by the source. Verify experimentally that W.

Figure 3: Resistor Network

Laboratory Report

Provide all measured resistance, voltage, and current values for the three circuits. Use simulation to calculate vo for both the voltage divider circuit without meter-loading and the voltage divider with the meter load connected. For the current divider circuit, you must simulate to compute all requested current values and use theory to compute their power values. Compute Rab theoretically for the resistive network.

An error analysis must be included with your report, comparing theoretical values to the experimental values measured in the laboratory. A general expression for % Error is given as

,

where Q denotes a particular quantity representing voltage, current, or power. An experimental (or measured) value is represented as , while a theoretical value is represented as .

In your laboratory report, include an introduction explaining the purpose of the lab. For each section (i.e., voltage divider, current divider, and resistor network), include how the circuits were set up and analyzed, the theoretical data, and the experimental data. Also include a discussion of experimental results. In this discussion, explain the behavior of the results (e.g., do the results make intuitive sense, do the results follow Kirchoff’s laws, and why are there deviations from the theoretical values?). When reporting the simulated values, experimental values, and percent error, use a table format for easy reading. Finish the report with a conclusion that states what was accomplished (proven or disproven), as well as lessons learned. You may turn in a single laboratory report for your group.

5 abR

i =

5 V 100 kW

a

b

10 kW10 kW

1 kW 1 kW

Rab

i

% Error = 100 exp th th

Q Q Q

Q -æ ö

ç ÷ è ø

expQ thQ