A relay is just a switch. The purpose of any switch is to turn something on and off. A relay turns HVAC equipment on or off. It’s that easy. A thermostat is also just a switch that turns HVAC ...
[Glitch] got his hands on a slew of relays which are meant for use in industrial equipment. They are designed to operate at 24V. He wanted to use these with common microcontrollers and instead of ...