INTRODUCTORY WORKSHOP IN ELECTROSTATICS

 

Dr John Chubb

John Chubb Instrumentation,

Unit 30, Lansdown Industrial Estate, Gloucester Road, Cheltenham, GL51 8PL, UK.

(Tel: +44 (0)1242 573347 Fax: +44 (0)1242 251388

email: jchubb@jci.co.uk Website: http://www.jci.co.uk)

The present Notes are prepared for the one 1 day ‘Introductory Workshop in Electrostatics’ to preceded the Institute of Physics 'ELECTROSTATICS 2003' International Conference at Heriot-Watt University Edinburgh 23-27 March 2003.

 

Contents:

1. INTRODUCTION

Nature of static electricity. Basic physics. Range of practical problems.

Importance of appreciating problems in context of practical 'systems'.

 

2. BASIC ELECTROSTATICS

Concepts, basic equations and relationships

 

3. INSTRUMENTS AND MEASUREMENTS

3.1 Introduction

3.2 Basic methods 3.2.1 Introduction

3.2.2 Measurement of electric field

3.2.3 Surface voltage

3.2.4 Space voltage

3.2.5 Charge

3.2.6 Surface charge density

3.2.7 Volume charge density

3.2.8 Charge transfer and currents in discharges

3.2.9 Incendivity of electrostatic discharges

3.2.10 Other measurements

3.2.11 Calibration

3.3 Assessment of materials 3.3.1 Introduction

3.3.2 Charge decay

3.3.3 Capacitance loading

3.3.4 Comments on other methods for measuring charge decay

3.3.5 High value resistor measurement

3.3.6 Chargeability

3.3.7 Shielding

3.4 Practical aspects

3.4.1 Measurement of atmospheric electric fields

3.4.2 Fieldmeters used as potemntiasl probes in large scale studies

3.4.3.Large scale Faraday Pail

3.4.5 Radio detetion of spark discharges

3.4.6 Industrial measurements

3.4.7 Modelling

 

4. ASSESSMENT OF SIGNIFICANCE OF STATIC

Criteria for concern about static: ignition of flammable gases and dusts, shock risks, cling of thin films, damage to semiconductors, upset of microelectronic system operation

 

5. APPROACHES TO TACKLE PROBLEMS

- Standards; Codes of Practice

- Changes to systems: earthing, avoid isolated conductors, reduce consequences, reduce charge generation, enhance dissipation, charge neutralisation, use only approved equipment

- Examples of practical problems and approaches to solve problems

- Sources of information

 

6. SOURCES OF INFORMATION ABOUT STATIC ELECTRICITY

7. DEFINITIONS

 

(These notes were last updated 28 February 2003)