CCT CCT Electrical & Electronic Calibration

Question 1

Which instrument is used as the primary reference for calibrating digital multimeters in an electrical calibration lab?

Accepted Answer

Multifunction calibrator

Answer

A multifunction calibrator (such as a Fluke 5700A or similar) generates precise, known voltage, current, and resistance values used as the reference when calibrating digital multimeters.

Question 2

What is the standard unit of electrical resistance in the SI system?

Accepted Answer

Ohm

Answer

The Ohm (Ω) is the SI unit of electrical resistance, defined as the resistance between two points when a constant potential difference of one volt produces a current of one ampere.

Question 3

When calibrating an AC voltmeter, which parameter is most important to verify in addition to amplitude accuracy?

Accepted Answer

Frequency response across the instrument's rated bandwidth

Answer

AC voltmeters must be verified for frequency response across their rated bandwidth because accuracy can degrade significantly at frequencies near or beyond the instrument's specified range.

Question 4

What is 'burden voltage' in the context of current calibration?

Accepted Answer

The voltage drop across a current-measuring instrument due to its internal resistance

Answer

Burden voltage is the voltage drop developed across a current-measuring instrument (such as a shunt or clamp meter) caused by its internal impedance, which can affect the circuit being measured.

Question 5

Which four-wire (Kelvin) measurement technique is used in precision resistance calibration to eliminate the effect of lead resistance?

Accepted Answer

Four-wire (Kelvin) connection

Answer

The four-wire (Kelvin) connection method uses separate current-source and voltage-sense leads, eliminating the resistance of the test leads from the measurement and improving accuracy for low-resistance values.

(CCT) Certified Calibration Technician Practice Test

(CCT) Certified Calibration Technician Practice Test

CCT CCT Electrical & Electronic Calibration