TS Equipment Calibration & Maintenance 2 — Questions and Answers
Question 1: Which document defines the acceptable tolerance limits for a piece of test equipment during calibration?
- Calibration certificate
- Equipment specification sheet (Correct answer)
- Maintenance log
- Traceability record
Correct answer: Equipment specification sheet
The equipment specification sheet defines the manufacturer's stated tolerance limits used as the acceptance criteria during calibration.
Question 2: A digital multimeter reads 10.05V when measuring a reference standard of exactly 10.00V. What is the absolute error?
- 0.5%
- 0.05V (Correct answer)
- 0.005V
- 5mV error ratio
Correct answer: 0.05V
Absolute error is the difference between the measured value and the true value: 10.05V − 10.00V = 0.05V.
Question 3: What is the primary purpose of a calibration interval?
- To schedule equipment cleaning
- To ensure equipment accuracy is verified before drift exceeds tolerance (Correct answer)
- To document equipment purchase dates
- To track technician certifications
Correct answer: To ensure equipment accuracy is verified before drift exceeds tolerance
Calibration intervals are set to ensure instruments are rechecked before accumulated drift can cause measurements to fall outside acceptable tolerance.
Question 4: When a temperature sensor is found out-of-tolerance during calibration, the correct first action is to:
- Adjust the sensor and return it to service
- Tag it out-of-service and notify affected test areas (Correct answer)
- Increase the calibration interval
- Document the finding and continue using it
Correct answer: Tag it out-of-service and notify affected test areas
An out-of-tolerance instrument must be removed from service and affected areas notified so prior measurements can be assessed for impact.
Question 5: Which calibration method involves comparing a device under test directly against a higher-accuracy reference standard?
- Indirect calibration
- Cross-calibration
- Direct comparison calibration (Correct answer)
- Statistical process control
Correct answer: Direct comparison calibration
Direct comparison calibration places the device under test side-by-side with a reference standard to measure the same quantity simultaneously.
Question 6: What does a calibration uncertainty budget account for?
- Equipment purchase cost
- All sources of measurement error contributing to the final uncertainty (Correct answer)
- Technician labor time
- Frequency of equipment failures
Correct answer: All sources of measurement error contributing to the final uncertainty
An uncertainty budget identifies and combines all individual uncertainty sources (reference standard, environment, resolution, repeatability) to produce a total measurement uncertainty.
Question 7: Which environmental factor most commonly affects the accuracy of precision resistance standards?
- Humidity
- Temperature (Correct answer)
- Vibration
- Barometric pressure
Correct answer: Temperature
Precision resistors have temperature coefficients, making temperature the dominant environmental influence on their resistance values.
TS Equipment Calibration & Maintenance 2
Which document defines the acceptable tolerance limits for a piece of test equipment during calibration?