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10.00 - Introduction

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An Arduino, Raspberry Pi, ESP32, or other microcontrollers can only handle a small amount of current on their GPIO pins. IF this current limit is exceeded then damage will occur. Many motors, lights, and other high power electrical devices cannot be switched directly with a micro controller. In order to switch high current loads with a low voltage signal, a relay is used. There are two common types of relays, mechanical relays and solid state relays.

Learning Objectives

  • Understand how relays work as power switches for heavy current loads
  • Use a relay in a circuit with an Arduino

Key Terms

  • Relay
  • Normally Open
  • Normally Closed
  • Common
  • Optoisolated
  • Solid State Relay
  • Mechanical Relay