General Theory
General information on transformers and measurement techniques
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.
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.
Hi-Pot Testing for Transformers
An explanation of Hi-Pot Testing for Transformers and 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.
Specific Transformer Types
Documents discussing common types of transformers and testing suggestions.
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.
DC Bias Testing
Information on DC Bias testing to check core performance
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.