CCT Electrical & Electronic Calibration Flashcards
6 cards from real CCT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CCT Electrical & Electronic Calibration flashcards as text
Which instrument is used as the primary reference for calibrating digital multimeters in an electrical calibration lab?
Answer: Multifunction calibrator
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.
What is the standard unit of electrical resistance in the SI system?
Answer: Ohm
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.
When calibrating an AC voltmeter, which parameter is most important to verify in addition to amplitude accuracy?
Answer: Frequency response across the instrument's rated bandwidth
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.
What is 'burden voltage' in the context of current calibration?
Answer: The voltage drop across a current-measuring instrument due to its internal resistance
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.
Which four-wire (Kelvin) measurement technique is used in precision resistance calibration to eliminate the effect of lead resistance?
Answer: Four-wire (Kelvin) connection
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.
What does 'loading effect' mean when calibrating voltage-measuring instruments?
Answer: The change in the measured voltage caused by the instrument drawing current from the source
Loading effect occurs when a voltmeter draws current from the circuit under test, causing a voltage drop and a reading lower than the true open-circuit voltage, which is significant with high-impedance sources.