On or Off

The thermostat

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• On–off control switches fully on or off around the setpoint.
• A band (hysteresis) prevents chattering.
• Wider band: fewer switches, bigger swings.

Steps

1. Switching around the setpoint
2. Comfort with less wear
3. How long per cycle?
4. Why not a band of zero?
5. Turning it up to max
6. Heating up