CST Strain Gauge & Piezoelectric Sensors 3

Question 1

What phenomenon occurs when a piezoelectric crystal is mechanically stressed and generates an electrical charge?

Accepted Answer

The direct piezoelectric effect

Answer

The direct piezoelectric effect describes the generation of electrical charge in a crystal when mechanical stress is applied.

Question 2

A load cell has a rated output of 2 mV/V. With a 10 V excitation, what is the full-scale output signal?

Accepted Answer

20 mV

Answer

Full-scale output = rated output × excitation = 2 mV/V × 10 V = 20 mV.

Question 3

Which material is most commonly used as the piezoelectric sensing element in industrial force sensors?

Accepted Answer

Quartz (SiO₂)

Answer

Quartz is the most widely used piezoelectric material in industrial sensors due to its stability, high modulus, and negligible pyroelectric effect.

Question 4

In a load cell with remote sense wiring (6-wire connection), what do the sense leads measure?

Accepted Answer

The actual excitation voltage at the load cell terminals

Answer

Remote sense leads allow the indicator to measure and compensate for voltage drop in the excitation supply leads, ensuring the load cell receives the correct excitation.

Question 5

What is 'hysteresis error' in a strain gauge load cell?

Accepted Answer

The difference in output between increasing and decreasing load at the same load value

Answer

Hysteresis is the difference in output readings at the same applied load when approached from increasing versus decreasing load directions.

(CST) Certified Scale Technicians Practice Test

(CST) Certified Scale Technicians Practice Test

CST Strain Gauge & Piezoelectric Sensors 3