Technical Document Library

Please find our range of technical articles below.

These cover a wide variety of transformer theory topics. Articles can be read on-line, or can be downloaded as PDFs.

General Theory

General information on transformers and measurement techniques

Transformer Basics

This document explains the basic theory and operation of transformers.

AC Theory

The complex current and voltage waveforms associated with many of today's AC power applications pose specific measurement problems.

Kelvin Connections

Outlines of methods and techniques to obtain high accuracy readings of low resistances.

Specific Test Types

Articles covering specific AT test options

Turns Ratio

An explanation of Turns Ratio and several methods to obtain best measurements.

Measuring Leakage Inductance

An explanation of Leakage Inductance in transformers, why it is important, and how to best perform measurements

Detecting Shorted Windings

This document outlines the methods used by the AT Series testers to find shorted windings.

Testing with Constant AC Current

How to test transformers at constant current. Covers testing above and below 2 Amps.

Laminate Transformer Testing

A document covering Laminate Transformers and methods for accurate testing.

Ferrite Transformer Testing

A tech note describing theory of Ferrite Transformers.

Testing Line Frequency Transformers

This describes the theory and answers common questions on Mains Voltage (50Hz/60Hz) Transformers.

Testing Audio & Telecom Transformers

Frequently asked questions about Audio and Telecommunications transformers.

Measurements for DC Chokes

This documents outlines test methods for all types of DC Chokes.

Testing Chokes and Transformers with High-Current DC Bias

A document covering DC BIAS testing using several different techniques.

Other Articles

Background info on AT Testers

Using the AT Series User Port

How to use the AT Series User Ports to switch your test fixture during a test for extra test coverage.

Relay Switching Techniques

The technical background to the AT Series testers. Explains how the nodes operate during testing to give accurate 4-wire measurements.