Which instrument typically houses a Bourdon tube?

• A. Thermometer
• B. Flow meter
• C. Pressure gauge
• D. Manometer

Answer: (C)

The Bourdon tube is the sensing element that converts pressure into a mechanical motion. It’s a curved, elastic tube that tends to straighten as internal pressure increases. That straightening moves a linkage and gears, which in turn drives the needle on a dial to show the pressure value. Because this mechanism directly translates pressure into a readable indication, it’s most commonly found in a pressure gauge.

Thermometers measure temperature using liquid expansion, resistance, or other temperature-sensing elements. Flow meters measure how fast a fluid is moving using diaphragms, orifices, turbines, or other flow-related sensors. Manometers rely on the imbalance of a liquid column to indicate pressure differences.