The heat anticipator in a heating-only thermostat is a(n) ____________ in series with ____________.

• A. large resistor, switch contacts
• B. tiny resistance heater, power supply
• C. tiny resistance heater, switch contacts
• D. capacitor, power supply

Answer: (C)

The heat anticipator works by adding a small, controlled amount of heat to the thermostat’s sensing element so it reaches the point where the contacts open slightly earlier, reducing overshoot in heating systems. This is achieved with a tiny resistance heater placed in series with the switch contacts. When the thermostat calls for heat, current flows through this small heater and warms the sensing mechanism, biasing it toward opening sooner than the room temperature alone would cause. Placing it in series ensures the anticipator’s heat only affects the switch during operation and tracks the load current for a consistent, quiet cycling behavior. It wouldn’t be effective if it were connected to the power supply or placed in parallel, and a large resistor would waste energy without providing the precise, small bias needed.