The differential in the temperature between the switch turning on the system and the temperature which it turns it off is called

The differential in the temperature between the switch turning on the system and the temperature which it turns it off is called

• A. Hysteresis
• B. Deadband
• C. Differential
• D. Setpoint

Answer: (C)

When a thermostat controls a system with on/off switching, it doesn’t flip states at the exact same temperature. Instead, there’s a band: the system turns on at a lower temperature and turns off at a higher one. The size of that band—the difference between the switch-on temperature and the switch-off temperature—is the differential. So, if heating starts at 65°F and stops at 68°F, the differential is 3°F. Changing the differential changes how often the system cycles: a larger differential means fewer cycles but bigger temperature swings; a smaller one means the system cycles more often. The setpoint is the target temperature you want to maintain, and while some contexts call this band a deadband or relate it to hysteresis, the term that directly describes the numeric gap between the on and off thresholds is differential.

When a thermostat controls a system with on/off switching, it doesn’t flip states at the exact same temperature. Instead, there’s a band: the system turns on at a lower temperature and turns off at a higher one. The size of that band—the difference between the switch-on temperature and the switch-off temperature—is the differential.

So, if heating starts at 65°F and stops at 68°F, the differential is 3°F. Changing the differential changes how often the system cycles: a larger differential means fewer cycles but bigger temperature swings; a smaller one means the system cycles more often. The setpoint is the target temperature you want to maintain, and while some contexts call this band a deadband or relate it to hysteresis, the term that directly describes the numeric gap between the on and off thresholds is differential.