CCT - Certified Calibration Technician Tools & Equipment Operation 1 — Questions and Answers
Question 1: When zeroing a micrometer before use, the thimble is closed against the anvil and a small discrepancy is noted on the barrel scale. What is the correct corrective action?
- Replace the micrometer immediately as it is out of tolerance
- Adjust the barrel using the spanner wrench provided with the instrument
- Add the offset value mentally to all subsequent readings
- Clean the anvil and spindle faces, then recheck before adjusting (Correct answer)
Correct answer: Clean the anvil and spindle faces, then recheck before adjusting
Dirt or debris on the contact faces is the most common cause of zero offset. Cleaning and rechecking first avoids unnecessary mechanical adjustment, which should only be performed if the error persists on clean surfaces.
Question 2: A calibration technician is using an electronic balance to weigh reference masses. The balance is level, warmed up, and recently calibrated, yet readings fluctuate by ±0.05 g. What is the most likely cause?
- The balance pan is overloaded beyond its rated capacity
- Air currents in the room are disturbing the balance pan (Correct answer)
- The internal calibration weight has drifted out of tolerance
- The AC power supply frequency is incompatible with the balance
Correct answer: Air currents in the room are disturbing the balance pan
Electronic balances at high resolution are extremely sensitive to air movement. Even slight drafts from HVAC vents or nearby personnel can cause the displayed reading to fluctuate, requiring a draft shield to stabilize results.
Question 3: When performing a calibration with an autocollimator, the instrument must be aligned along the optical axis of the reflector. What happens if significant angular misalignment is present?
- The autocollimator overheats and shuts down automatically
- The reflected beam misses the reticle, producing no readable return signal (Correct answer)
- Measurement accuracy improves because a larger reflection area is sampled
- The instrument defaults to a coarser resolution range automatically
Correct answer: The reflected beam misses the reticle, producing no readable return signal
An autocollimator relies on a collimated beam being reflected back through the objective lens. Excessive angular misalignment causes the return beam to miss the internal detector or reticle entirely, resulting in no valid measurement output.
Question 4: A technician connects an oscilloscope probe to a calibration signal generator and observes a distorted waveform with significant ringing. The most likely corrective action is to:
- Increase the generator output amplitude to overcome probe loading
- Adjust the probe's compensation trimmer until the square wave edges are clean (Correct answer)
- Replace the oscilloscope with a higher-bandwidth model
- Switch to a 1× probe setting to reduce signal attenuation
Correct answer: Adjust the probe's compensation trimmer until the square wave edges are clean
Probe compensation adjusts the high-frequency response of the RC network in the probe tip to match the oscilloscope input impedance. Incorrect compensation causes overshoot, ringing, or rounded edges on square waves and must be corrected before any measurement.
Question 5: During pneumatic pressure calibration, a technician notices a slow, steady decline in the reference pressure reading while the system supply valve is closed. This observation most likely indicates:
- The reference gauge has a non-linear response at this pressure range
- There is a leak in the test circuit connections or tubing (Correct answer)
- The pneumatic supply pressure has exceeded the gauge's full-scale rating
- Atmospheric pressure changes are affecting the gauge reference port
Correct answer: There is a leak in the test circuit connections or tubing
A slow pressure decay with the supply isolated is a classic symptom of a leak in the circuit. Fittings, tubing, and adapters must be inspected and leak-tested before proceeding, as any leak invalidates the calibration results.
Question 6: A technician uses a surface roughness tester (profilometer) to verify a reference artifact. Before traversing the stylus, the instrument should be:
- Warmed up under full traversal load for 30 minutes
- Leveled so the traverse direction is horizontal within specification (Correct answer)
- Zeroed by pressing the stylus firmly onto the reference surface
- Calibrated only after completing the full measurement traverse
Correct answer: Leveled so the traverse direction is horizontal within specification
A profilometer measures surface height deviations along the traverse axis; gravity-induced stylus sag due to instrument tilt introduces a false slope error across the measured profile. The instrument must be leveled so the traverse is horizontal before measurement.
CCT - Certified Calibration Technician Tools & Equipment Operation 1
When zeroing a micrometer before use, the thimble is closed against the anvil and a small discrepancy is noted on the barrel scale.
What is the correct corrective action?