ISCET Test Equipment and Measurement 3

Question 1

A technician connects a voltmeter with an input impedance of 10 MΩ across a 10 MΩ resistor in a circuit. What is the effective resistance seen by the circuit?

Accepted Answer

5 MΩ

Answer

Two equal resistances in parallel yield half the value: 10 MΩ ∥ 10 MΩ = 5 MΩ, significantly loading the circuit.

Question 2

On an analog VOM, the ohmmeter scale reads from right to left with zero on the right. Why is this scale non-linear?

Accepted Answer

Ohm's law causes a non-linear relationship between current and resistance

Answer

Resistance is inversely proportional to current (R = V/I), which produces a compressed, non-linear scale crowded at the high-resistance end.

Question 3

Which oscilloscope trigger mode causes the sweep to run continuously even when no trigger event occurs?

Accepted Answer

Auto

Answer

Auto mode allows the sweep to free-run when no trigger is detected, ensuring a trace is always visible.

Question 4

A logic analyzer differs from an oscilloscope primarily because it:

Accepted Answer

Captures and displays many digital channels simultaneously with time correlation

Answer

A logic analyzer captures multiple digital lines simultaneously and allows protocol decoding and timing analysis across all channels.

Question 5

When calibrating a DMM, the technician applies a precise 10.0000 V reference and the meter reads 9.9850 V. What is the meter's absolute error?

Accepted Answer

−0.0150 V

Answer

Absolute error = measured value − true value = 9.9850 − 10.0000 = −0.0150 V.

(ISCET) International Society of Certified Electronics Technicians Practice Test

(ISCET) International Society of Certified Electronics Technicians Practice Test

ISCET Test Equipment and Measurement 3