How to measure correctly - measurement technique and measurement error in electronics

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Written by: Dieter Nührmann
Category: Books
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Dieter Nührmann, Wydawnictwa Komunikacji i Łączności, Warsaw 1978
Translated from the German by Dr. Andrzej Wójciak

TABLE OF CONTENTS

PREFACE (9)

   When the series of articles entitled "How to Measure Correctly" appeared in the journal FUNKSCHAU, neither the publisher nor the author anticipated the enormous interest it generated. The interest in the subject matter was so great that it prompted the preparation of this expanded and revised book, "How to Measure Correctly - Measurement Technique and Measurement Error in Electronics."

   Modern measurement technology in electronics already encompasses so many different measurement methods and techniques that the author decided to give the young technician - to whom this book is primarily addressed - not only an overview of them, but also a practical introduction.

   The title, "How to Measure Correctly – Measurement Technique and Measurement Error in Electronics," highlights a fundamental issue. Performing a measurement can be simple and straightforward, provided the correct measurement method is chosen. For this reason, the book comprehensively describes each measurement method. More importantly, however, the author always highlights the potential for measurement error.

   So, is measurement technology in electronics bristling with difficulties? Certainly, it is—wherever a "newly minted" technician lacks practical knowledge, that is, the experience gained over many years of solving a variety of measurement tasks.

   So what are these difficulties? If, for example, we turn on a soldering iron or a television set, their operation can be observed very easily. We can see the solder melting, the image appearing on the screen, and we can hear the sound. This is, as it were, "measuring practice"—an experience we are proficient in.

   The situation is different in electronic measurement technology. In the case of a soldering iron, we can determine electrical power consumption using a voltmeter or ammeter. The needle indicates a specific value – and this is where the problem begins. We trust this reading and don't consider its origins or the errors it might contain. And if, for example, we are measuring the frequency response of a high-frequency amplifier in a television receiver, we also trust the first measurement result obtained. This trust seems justified, because we assume that the measuring instrument will always select a useful and correct result for the system under test. However, we should remember that the measuring instrument will only indicate the value of the signal that is fed to it, and even then with an error dependent on its inherent accuracy. And it is precisely this signal feed that is a significant problem in all electronic measurement technology. For these reasons, I have placed significant importance on presenting individual measuring instruments, their applications, and measurement methods. I have particularly considered possible measurement errors and – what seems even more important – the methods for recognizing them.

   At this point, I would like to wish the reader that reading this introduction to measurement practice will prove useful to him.

DIETER NÜHRMANN
Achim, 1974

  1. MEASURED QUANTITIES IN ELECTRONICS - UNITS AND CONCEPTS (11)
    1. DC Voltages (11)
    2. AC Voltages (11)
    3. DC Currents (12)
    4. AC Currents (12)
    5. Elements (12)
    6. Frequencies (13)
    7. Bandwidth (14)
    8. Internal Generator Impedance (Matching) (16)
    9. Impulses, Pulse Voltages (17)
    10. Frequency Deviation, Sweep Deviation, Modulation Depth (21)
    11. Tolerances and Their Meaning (22)
    12. Decibels (25)
  2. BASIC MEASUREMENT TECHNIQUES (27)
    1. Tests, Measurements, Scaling (27)
    2. Tests (Checking) (27)
    3. Measurements (28)
    4. Scaling (28)
  3. BASIC ERRORS MEASUREMENTS
  4. PERMITTED ERROR LIMITS IN ELECTRONICS, RADIO BROADCASTING, AND TELEVISION TECHNOLOGY (36)
    1. Measurements of operating and supply voltages (36)
    2. Measurements to determine the operating point (38)
  5. DC VOLTAGE MEASUREMENTS (41)
    1. DC voltage measurements with a multi-range device (41)
    2. DC voltage measurements with superimposed pulse waveforms (44)
    3. DC voltage measurements at the terminals of sources with very high internal resistance (47)
    4. DC voltage measurements with superimposed alternating current (49)
  6. DC CURRENT MEASUREMENTS (53)
    1. DC currents (without alternating current components) (53)
    2. DC current measurements with superimposed pulse waveforms (55)
  7. AC VOLTAGE MEASUREMENTS AND PULSE CURRENTS (57)
    1. Sinusoidal Voltages (57)
    2. Pulse Voltages (58)
    3. High Frequency Voltages (61)
    4. Low Frequency Voltages (70)
    5. Measurements of AC Voltages at the Terminals of High-Resistance Sources (72)
    6. Pulse Currents (72)
  8. COMPONENT MEASUREMENTS (74)
    1. Capacitor Measurements (74)
    2. Inductor Measurements (77)
    3. Resistors Measurements (80)
    4. Thermistors, Varistors, and Photoresistors Measurements (86)
    5. Transformer Measurements (89)
    6. Vacuum Tube and Semiconductor Measurements (92)
  9. FREQUENCY MEASUREMENTS (100)
    1. Frequency Measurements Using a Frequency Meter (100)
    2. Frequency Measurements Using the Absorption Method (101)
    3. Frequency Measurements by Comparison (Beat Method) (101)
  10. MEASUREMENTS OF SELECTIVE AMPLIFIERS - SWOBULATION TECHNIQUE (104)
  11. OSCILLOSCOPES (117)
    1. Introduction (117)
    2. Oscilloscope Components (118)
      1. Oscilloscope Tube. Screen (118)
      2. Image Focus (120)
      3. Brightness (Image Brightness) (123)
      4. Grid (124)
    3. Vertical Deflection Amplifier (126)
      1. Field of View (126)
      2. Bandwidth (126)
      3. Input Sensitivity (129)
      4. Input Switch and Gain Control (130)
      5. Probe (132)
      6. Image Shift (137)
    4. Delay Line (138)
      1. Time Base (139)
      2. Trigger Amplifier (144)
      3. Time Base Generator (149)
      4. Stretched Time Base (150)
    5. Horizontal Deflection Amplifier (151)
      1. Sensitivity (151)
      2. Bandwidth (152)
      3. Deflection Types (153)
    6. Dual-Beam Technique (153)
    7. Applications (155)
      1. Direct Voltage Measurements (155)
      2. Alternating Voltage Measurements (Sinusoidal) (157)
      3. Alternating Voltage Measurements (Pulsed) (165)
      4. Wobularscope Measurements (169)
      5. Simultaneous Use of Inputs X and Y (171)
    8. Service Oscilloscope Circuit Description (173)
  12. MULTIRANGE METER (178)
    1. Basic Data (178)
    2. Diagram and Scope of Applications (178)
    3. Possible Measurement Errors (180)
  13. ELECTRONIC VOLTMETER (MULTIMETER) (182)
    1. Basic Data (182)
    2. Diagram and Scope of Applications (182)
  14. AM-FM SIGNAL GENERATOR WITH BUILT-IN WOBULATOR (186)
    1. Basic Data (186)
    2. Description of the AM-FM Signal Generator (187)
      1. Wobulator (187)
      2. Generator (190)
    3. Applications (193)
      1. Tuning the AM Receiver (193)
      2. Tuning the AM-FM Intermediate Frequency Path (195)
      3. Passive Marker Generation (200)
  15. REGULATED ISOLATION TRANSFORMER (203)
    1. Construction of a Regulated Isolation Transformer (203)
    2. Switching On and Possible Measurement Errors (204)
  16. STABILIZED POWER SUPPLY (206)
    1. Measurement Errors Caused by Stabilized Power Supplies (206)
  17. WOBULATOR (209)
    1. Operation Principle and Applications (209)
    2. Errors in Operation with the Wobulator (211)
      1. Too High Sweep Frequency (211)
      2. Incorrect Oscilloscope Connection (213)
      3. Errors caused by irregularities in the wobulator amplitude characteristics (216)
      4. Incorrect positioning of the demodulated signal (217)
      5. Errors caused by incorrect signal input (218)
      6. Phase discriminator measurement errors (219)
      7. Measurement errors caused by higher harmonics (221)
      8. Other errors related to the amplifier time constant (222)
      9. Errors caused by incorrect wobulator setting (222)
      10. Errors caused by the superposition of extraneous high-frequency signals (223)
    3. Basic wobulator diagram (224)

INDEX (225)