### Electromagnetism

Examples of electrode patterns and corresponding electrostatic field simulations

(click figure to enlarge)

## LEEI-10 Electrostatic Field Mapping Apparatus

Features

• Intuitive and clear configuration

• Convenient operation

• Stable and reliable measurements

Introduction

In engineering applications, it is often needed to know the electric field distribution of an electrode system in order to study the motion behavior of the electrons or charged particles in an electric field. For example, the electric field distribution of the electrodes in an oscilloscope tube should be known for the study of electron beam focusing and deflection in the oscilloscope tubes.

In general, mathematical analysis or experimental simulation can be used to derive the distribution of an electric field. The former method is normally used for simple cases while the latter method should be used for complicate electrode systems.

Simulation method uses an easy-to-implement or easy-to-measure physical process to substitute an inconvenient-to-implement or not-easy-to-measure physical process. It requires that the two states or two sets of physical quantities in two physical processes have a one-to-one corresponding relationship, similar mathematical expressions, and similar boundary conditions. For a stable physical field, once its differential equations and boundary conditions are determined, its solution is unique. Since a steady current field has the same mathematical expressions and boundary conditions as an electrostatic field, it is used to simulate the electrostatic field.

The configuration of this experimental apparatus is intuitive and clear. A two-level structure is used for positioning in plane and point sampling in synchronous. It is convenient to operate and the measurement data is stable and reliable.

Using this apparatus, students can:

1. Learn to study electrostatic fields using simulation method.

2. Deepen the understanding on concepts of strength and potential of electric fields.

3. Map the equipotential lines and electric field lines of the two electrode patterns of a coaxial cable and a pair of parallel wires.

Specifications

 Description Specifications Power supply 0 ~ 15 VDC, continuously adjustable Digital voltmeter range -19.99 V to 19.99 V, resolution 0.01 V Parallel wire electrodes Electrode diameter 15 mmDistance between electrodes 95 mm Coaxial electrodes Diameter of central electrode 15 mmWidth of ring electrode 10 mmInner diameter of ring electrode 150 mm

Parts List

 Item Qty Main electric unit 1 Conductive glass and carbon paper support 1 Probe and needle  support 1 Conductive glass plate 2 Connection wire 4 Carbon paper 100 sheets A4 size Coordinate paper 100 sheets A4 size Paper clamps 4 Optional conductive glass plate: focusing electrode & non-uniform field electrode each one Instruction manual 1 (Electronic version)

Examples of electrode patterns and corresponding electrostatic field simulations

(click figure to enlarge)