A technician must configure a digital multimeter properly before taking electrical reading… — Armed Services Vocational Aptitude Battery (ASVAB)

A technician must configure a digital multimeter properly before taking electrical readings on various systems. Which of the following correctly pairs each multimeter function or terminal with its required circuit connection method?

DC Voltage ( $V_{\text{DC}}$ ) ModeConnected in parallel across an energized component to measure steady polarity potential difference
AC Voltage ( $V_{\text{AC}}$ ) ModeConnected in parallel across line terminals to evaluate alternating sinusoidal potential
DC Current ( $A_{\text{DC}}$ ) ModeInserted in series into an opened conductor path so electron flow travels through the meter
Common ( $\text{COM}$ ) TerminalAccepts the black reference probe for all standard voltage and current testing

Answer

DC Voltage Mode pairs with parallel connection across steady DC components; AC Voltage Mode pairs with parallel connection across alternating lines; DC Current Mode pairs with series insertion into an opened circuit path; and Common (COM) Terminal pairs with accepting the black reference test probe.

Voltage measurements (both AC and DC) require parallel connections across components because voltmeters feature high internal impedance that will not alter circuit operation. Current measurement requires opening the conductor path and inserting the low-impedance ammeter in series so that all electron flow passes through the meter. The COM jack serves as the permanent return path for the black probe.

Step-by-Step Solution

Identify the proper connection topologies for voltage versus current measurements.

Voltage is always measured across components in parallel, while current requires opening the path and placing the meter in series.

Voltmeters feature high internal resistance to prevent drawing load current, whereas ammeters feature near-zero internal resistance to allow circuit current to flow through uninterrupted.

Distinguish between direct current (DC) and alternating current (AC) voltage settings.

DC voltage evaluates constant-polarity sources, while AC voltage evaluates oscillating line waveforms.

Multimeters use separate internal rectifying and filtering circuits to accurately calculate alternating signals versus constant potential.

Determine the universal function of the multimeter Common (COM) jack.

The COM jack is the return reference port for the black probe across all voltage and current tests.

A fixed zero-potential reference point is required for the meter to accurately compare potential or complete the current measurement loop.

Key Concept

Multimeter Connection Topologies and Input Terminals for Voltage and Current

Estimated Time:45s

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