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"INTRODUCTION TO ELECTROSTATIC MEASUREMENTS"

by John Chubb

Contents:

PREFACE

1. INTRODUCTION Nature of static electricity. Basic physics. Range of practical problems. Importance of appreciating problems in context of practical 'systems'.

2. BASIC ELECTROSTATICS

2.1 Introduction

2.2 Charge

2.3 Force between charges

2.4 Electric field

2.5 Potential

2.6 Electric flux density

2.7 Gauss' law

2.8 Induced charge

2.9 Capacitance

2.10 Energy

2.11 Poisson's equation

2.12 Dielectrics

2.13 Charge migration and dissipation

2.14 Charge separation mechanisms

2.15 Electrical breakdown

3. INSTRUMENTS

3.1 Introduction

3.2 Measurement of electric field

3.2.1 Basic aspects

3.2.2 Induction probe instruments

3.2.3 Field mill fieldmeters

3.2.4 General requirements for fieldmeters

3.2.5 Field mill fieldmeters without earthing of rotating chopper

3.2.6 Zeroing fieldmeters

3.2.7 Calibration of fieldmeters

3.2.8 Factors determining performance of field mill fieldmeters

3.3 Measurement of charge

3.3.1 Introduction

3.3.2 Faraday Pail

3.3.3 Charge measurement

3.4 Assessment of materials 3.4.1 Introduction

3.4.2 Surface voltage from retained charge

3.4.3 Comments on methods for charge decay measurement

3.4.4 Corona charge decay measurement

3.4.5 Capacitance loading

3.5 Measurement of shielding performance

3.5.1 Introduction

3.5.2 An alternative method of testing

3.5.3 Relationship of shielding to effective resistivity

3.6 Measurement of charge transfer and currents in discharges

3.7 Measurement of resistance

3.8 Measurement of capacitance

4. PRACTICAL ELECTROSTATIC MEASUREMENTS

4.1 Introduction

4.2 Fieldmeter measurements

4.3 Measuring surface voltage

4.4 Electrostatic voltmeter

4.5 Measuring potentials in a volume

4.6 Measurement of charge

4.7 Surface charge density

4.8 Volume charge density

4.9 Charge decay for assessing materials

4.10 Measurements on discharges

4.11 Radio detection of sparks ?Äì radio spectrum

4.12 Lightning warning

4.13 Incendivity of electrostatic discharges

4.14 Shielding

4.15 Other measurements

4.16 Modelling

4.17 Calibration

5. ASSESSMENT OF SIGNIFICANCE OF STATIC

5.1 Introduction

5.2 Ignition of flammable atmospheres

5.3 Shock risks

5.4 Attraction of dust, debris and thin films

5.5 Damage to semiconductor devices

5.6 Upset operation of microelectronic systems

6. APPROACHES TO TACKLE PRACTICAL PROBLEMS

6.1 General comments

6.2 Is static the cause?

6.3 Codes of practice

6.4 Characteristics of materials

6.5 Investigative procedures

6.6 System changes

7. EXAMPLES FROM EXPERIENCE

7.1 Introduction

7.2 Cleanroom clothing

7.3 Tanker studies

7.4 Food product silo

7.5 Lightning warning

7.6 Car seats

7.7 Electrostatic safety at solvent extraction

7.8 Airborne particles

7.9 Airborne fibre monitor

7.10 Coated metal sheets

7.11 Adhesive manufacture

7.12 Health monitor

8. SOURCES OF INFORMATION ABOUT STATIC ELECTRICITY

8.1 General

8.2 Organisations arranging conferences and meetings

8.3 Information on meetings

8.4 Journals for publication of papers

8.5 Directories

8.6 Standards

8.7 Shell Safety Guide

8.8 Books

Annex 1: Definitions

Annex 2: Test method to assess the influence of static charge retained on materials

Annex 3: Calibration procedures

Annex 4: Papers by John Chubb on static electricity

POSTSCRIPT



John Chubb
2 Monica Drive, Piville, Cheltenham, GL50 4NQ, UK
Tel:+44 (0)1242 573454 Fax: +44 (0)1242 573454
email: jchubb@infostatic.co.uk

© John Chubb

Page Updated : 7/2/2009