What is the bourbon tube used on instruments for?

What is the bourbon tube used on instruments for?

• A. Temperature and humidity
• B. Pressure and humidity
• C. Altitude and speed
• D. Pressure and temperature

Answer: (D)

The key idea is that a bourdon tube is a sensing element designed to measure pressure. It’s a curved, hollow tube that tends to straighten as internal pressure increases, and that deflection is converted into a needle movement to indicate pressure on a gauge. Temperature can influence the tube’s behavior—changing its dimensions and elasticity—so in many instruments you see temperature effects accounted for or compensated. That combination of sensing pressure and the practical impact of temperature on the reading is why this type of instrument is described in terms of both pressure and temperature. It isn’t used to measure humidity, altitude, or speed, which is why those options don’t fit.

The key idea is that a bourdon tube is a sensing element designed to measure pressure. It’s a curved, hollow tube that tends to straighten as internal pressure increases, and that deflection is converted into a needle movement to indicate pressure on a gauge. Temperature can influence the tube’s behavior—changing its dimensions and elasticity—so in many instruments you see temperature effects accounted for or compensated. That combination of sensing pressure and the practical impact of temperature on the reading is why this type of instrument is described in terms of both pressure and temperature. It isn’t used to measure humidity, altitude, or speed, which is why those options don’t fit.