🔍 Key Concepts

• Bourdon tube pressure gauge mechanism – how motion of the tube is transmitted to the pointer • Difference between range/proportional band adjustment and simple zero adjustment • What parts of the gauge affect mechanical leverage vs. calibration marks

💭 Think About

• Ask yourself: which option changes the mechanical ratio between tube movement and pointer movement, rather than just moving the pointer on the dial? • Consider how a small motion at the bourdon tube is amplified into a larger pointer sweep – which component in the list directly alters that amplification? • Which changes would alter the actual pressure–deflection behavior of the tube itself (its elasticity), and which only change the linkage/indication?

✅ Before You Answer

• Distinguish clearly between changing the tube’s physical characteristics vs. changing the linkage geometry. • Identify which choice would be used for calibrating span/range (how many psi per degree of pointer movement) rather than just setting zero. • Eliminate any option that only shifts the pointer reading without changing the underlying pressure-to-deflection ratio.