March 2010

Doc ID 3579 Rev 3

1/16

AN441

Application note

Inductive load control with AC switches

Introduction

AC switches are now commonly used as static switches to drive inductive loads such as

magnetic transformers, valves, induction motors, etc.

This application note describes the particular points to focus on when such loads are

controlled by AC switches like Triac, ACS or ACST. For example, there is an explanation of

just when a Triac has to be triggered to reduce the inrush current at turn on.

Typical examples are given for magnetrons used in microwave ovens, transformers for SELV

halogen lamps, and universal motors used in vacuum cleaners.

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