What principle does the Bourdon tube gauge rely on to indicate pressure?

Prepare for the Engineman EN A School Test 1. Utilize flashcards and multiple choice questions with detailed explanations to boost confidence and readiness for the test.

The principle being tested is the mechanical deflection of a curved tube as pressure changes. A Bourdon tube is a hollow, curved metal tube that tends to straighten when internal pressure increases. As pressure drives outward on the tube walls, the curvature reduces and the tube uncoils slightly. This small movement is transmitted through a linkage and gearing to move a pointer on a calibrated dial, providing a pressure reading. Since this relies on the tube’s elasticity and geometry to convert pressure into motion, it’s not about electrical resistance, magnetic fields, or optical effects, which is why those other options don’t apply here.