Resistance type temperature indicators using Wheatstone bridge or ratio meter circuits may be used to indicate the temperatures of which of the following?

Resistance type temperature indicators using Wheatstone bridge or ratio meter circuits may be used to indicate the temperatures of which of the following?

• A. Ambient cabin temperature
• B. Engine exhaust temperature
• C. Carburetor air, coolant, oil temperature
• D. Tire temperature

Answer: (C)

Resistance-type temperature indicators rely on sensors whose resistance changes with temperature, such as RTDs or thermistors. When these sensors are placed in a Wheatstone bridge or a ratio meter circuit, the small changes in resistance produce a proportional voltage signal, giving a precise indication of temperature. This setup is especially suited to engine-related temperatures—carburetor air, coolant, and oil—where accurate, stable readings are needed to monitor and control engine operation. The other options are less fitting: ambient cabin temperature isn’t typically read by these engine-focused resistance sensors, tire temperature uses different sensing approaches, and engine exhaust temperature is usually measured with thermocouples due to the higher, more extreme temperature range.

Resistance-type temperature indicators rely on sensors whose resistance changes with temperature, such as RTDs or thermistors. When these sensors are placed in a Wheatstone bridge or a ratio meter circuit, the small changes in resistance produce a proportional voltage signal, giving a precise indication of temperature. This setup is especially suited to engine-related temperatures—carburetor air, coolant, and oil—where accurate, stable readings are needed to monitor and control engine operation. The other options are less fitting: ambient cabin temperature isn’t typically read by these engine-focused resistance sensors, tire temperature uses different sensing approaches, and engine exhaust temperature is usually measured with thermocouples due to the higher, more extreme temperature range.