PH250_Lab_Manual_1

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School

Brigham Young University, Idaho *

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Course

250

Subject

Electrical Engineering

Date

Oct 30, 2023

Type

pdf

Pages

182

Uploaded by AI_Theta_RWBY

PH 250 Intermediate Physics Laboratory for Physics and Physical Science Teaching Majors R Todd Lines David Oliphant Kevin Kelley May 17, 2022

Contents Preface xi Introduction xiii Keeping a Lab Notebook . . . . . . . . . . . . . . . . . . . . . . . xiii Using This Lab Manual . . . . . . . . . . . . . . . . . . . . . . . xiv I Computer Interfacing 1 1 Introduction to the Arduino 3 1.1 Building circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1.1 Temporary circuits: the prototyping board . . . . . . . . 4 1.1.2 Durable circuits: soldering . . . . . . . . . . . . . . . . . . 8 1.2 Arduino Circuit Control . . . . . . . . . . . . . . . . . . . . . . . 14 1.2.1 Attaching the Arduino to the circuit . . . . . . . . . . . . 14 1.2.2 The Arduino sketch: an introduction . . . . . . . . . . . . 16 1.2.3 Compiling and uploading the sketch . . . . . . . . . . . . 19 1.3 Adding More Complexity . . . . . . . . . . . . . . . . . . . . . . 21 2 Electrical Measuring Devices 25 2.1 What We Measure: Voltage . . . . . . . . . . . . . . . . . . . . . 26 2.2 Sources of DC and AC potentials . . . . . . . . . . . . . . . . . . 28 2.2.1 DC Power Supply . . . . . . . . . . . . . . . . . . . . . . 29 2.2.2 Signal Generator . . . . . . . . . . . . . . . . . . . . . . . 30 2.3 Instruments for Measuring Voltage . . . . . . . . . . . . . . . . . 31 2.3.1 Voltmeters . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.3.2 Oscilloscopes . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.4 Measurement Uncertainty: A Review . . . . . . . . . . . . . . . . 36 2.5 Measuring Something Else: Current . . . . . . . . . . . . . . . . 37 2.5.1 Current is a Flow . . . . . . . . . . . . . . . . . . . . . . . 38 2.5.2 The Physics of Measuring Electric Current . . . . . . . . 40 2.5.3 How to Build an Ammeter . . . . . . . . . . . . . . . . . 45 2.5.4 Testing the New Instrument . . . . . . . . . . . . . . . . . 45 2.6 Propagation of Uncertainty: A Review . . . . . . . . . . . . . . . 47 iii

iv CONTENTS 2.7 Calculating the Uncertainty in Current . . . . . . . . . . . . . . . 51 3 First DAQ Measurements: Voltage 53 3.1 Building a Voltmeter . . . . . . . . . . . . . . . . . . . . . . . . . 55 3.1.1 Analog Pins on the Arduino . . . . . . . . . . . . . . . . . 56 3.1.2 Analog to Digital Conversion . . . . . . . . . . . . . . . . 56 3.1.3 Sending the Data to the Computer . . . . . . . . . . . . . 59 3.1.4 Wiring the simple voltmeter . . . . . . . . . . . . . . . . . 61 3.1.5 Seeing the data . . . . . . . . . . . . . . . . . . . . . . . . 61 3.2 Extending our voltmeter with a voltage divider . . . . . . . . . . 64 3.3 Practice Problems . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4 AC Voltages and the Arduino 73 4.1 The Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4.2 Sampling Theory, a complication . . . . . . . . . . . . . . . . . . 78 5 Getting Data to the Computer 83 5.1 How to get Python . . . . . . . . . . . . . . . . . . . . . . . . . . 84 5.1.1 Getting Anaconda Python . . . . . . . . . . . . . . . . . . 84 5.1.2 Getting the PySerial library for Anaconda . . . . . . . . . 86 5.2 Getting data from the Arduino . . . . . . . . . . . . . . . . . . . 87 5.3 Getting Pyserial if you have a Mac . . . . . . . . . . . . . . . . . 93 5.3.1 Anaconda Mac Users 4.1.2 . . . . . . . . . . . . . . . . . . 93 5.3.2 Manually install Pyserial using the Terminal app . . . . . 94 5.3.3 Mac Paths and Port Notation . . . . . . . . . . . . . . . . 94 6 DataLogging 99 6.1 Arduino Shields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 6.2 Data Logger Shield . . . . . . . . . . . . . . . . . . . . . . . . . . 101 6.3 Setting up the data logging shield . . . . . . . . . . . . . . . . . . 101 6.4 Powering the Arduino . . . . . . . . . . . . . . . . . . . . . . . . 106 II Testing Models 109 7 Validation of Ohm’s Law 111 7.1 Ohm’s Law Revisited . . . . . . . . . . . . . . . . . . . . . . . . . 111 7.2 Measuring current with our Arduino . . . . . . . . . . . . . . . . 113 7.3 Making an Arduino measure current . . . . . . . . . . . . . . . . 114 7.3.1 Choosing shunt resistors . . . . . . . . . . . . . . . . . . . 117 7.4 Finding Uncertainty in a Calculated Value . . . . . . . . . . . . . 119 7.4.1 Iterate to find an optimal value . . . . . . . . . . . . . . . 121 7.5 Using statistics to calculate uncertainty . . . . . . . . . . . . . . 124 7.6 Philosophical warning . . . . . . . . . . . . . . . . . . . . . . . . 126

CONTENTS v 8 Resistors and Capacitors 129 8.1 The Model to Test . . . . . . . . . . . . . . . . . . . . . . . . . . 130 8.2 The Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 8.3 Fitting the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 8.3.1 LoggerPro Curve Fitting . . . . . . . . . . . . . . . . . . . 136 9 Series RLC Circuits, Part I 143 9.1 The Model: Self Inductance . . . . . . . . . . . . . . . . . . . . . 144 9.1.1 Inductance of a solenoid . . . . . . . . . . . . . . . . . . . 145 9.2 RLC Series circuits . . . . . . . . . . . . . . . . . . . . . . . . . . 146 III Student Designed Experiments 153 10 Writing a Proposal 155 10.1 Statement of the experimental problem . . . . . . . . . . . . . . 155 10.2 Procedures and anticipated difficulties . . . . . . . . . . . . . . . 155 10.3 Proposed analysis and expected results . . . . . . . . . . . . . . . 156 10.4 Preliminary list of equipment needed . . . . . . . . . . . . . . . . 156 10.5 Designing the experiment . . . . . . . . . . . . . . . . . . . . . . 157 10.6 Using uncertainty to refine experimental design . . . . . . . . . . 157 11 Student Designed Experiments 161 11.1 Proposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 11.2 Performing the experiment . . . . . . . . . . . . . . . . . . . . . 162 11.3 Written report . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 11.4 Oral report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 11.5 Lab Notebook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 11.5.1 Designing the Experiment . . . . . . . . . . . . . . . . . . 163 11.5.2 Performing the Experiment . . . . . . . . . . . . . . . . . 164

vi CONTENTS

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