🔍 Key Concepts

• Piezoelectric effect in quartz crystals • Relationship between applied DC voltage and mechanical deformation in piezoelectric materials • Limits of operation: what happens when voltage exceeds rated values for a crystal

💭 Think About

• Think about what the piezoelectric effect actually does: when you apply a voltage across a quartz crystal, what kind of change (if any) occurs in the crystal lattice? • Is the behavior the same for any amount of DC voltage, or is there a difference between normal operating voltage and excessive voltage? • Consider whether the exam is asking about the normal effect of DC voltage, a damage condition, or both.

✅ Before You Answer

• Clarify in your mind whether all applied DC voltages cause a visible/measurable physical distortion in the crystal plate • Consider whether overvoltage can mechanically damage a quartz crystal (e.g., cracking) due to stress • Check if any option uses the word always or combines normal operation with a damage scenario, and decide if that matches real crystal behavior