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Difficulty: EasyMultimeter: Resistance and Continuity

An apprentice technician connects digital multimeter test leads across an unpowered, unbroken length of copper wire to verify circuit continuity. Which multimeter response confirms that the wire provides a continuous, unbroken electrical path?

  1. A
    An overload or open-loop reading (OL\text{OL}) with no tone
  2. A continuous audible tone accompanied by a resistance reading near 0 Ω0\ \OmegaAnswer
  3. C
    A very high resistance reading in the megaohm (MΩ\text{M}\Omega) range
  4. D
    A fluctuating DC voltage reading measured in millivolts (mV\text{mV})

Answer

A continuous audible tone accompanied by a resistance reading near 0 Ω0\ \Omega
When a digital multimeter is set to continuity mode, it sends a tiny test current through the leads. When placed across an unbroken conductor, the resistance is nearly 0 Ω0\ \Omega, which closes the test loop and activates the meter's audible beeper.

Step-by-Step Solution

1
Identify the purpose of a continuity check
A continuity test verifies whether an unbroken path exists for electrical current to flow.
Continuity requires a low-resistance physical connection between two test points.
2
Determine the expected resistance and meter behavior for a good conductor
An intact copper conductor exhibits minimal resistance (close to 0 Ω0\ \Omega), which causes the multimeter's internal continuity buzzer to sound continuously.
Digital multimeters sound a continuous audible beep when the measured resistance across the leads is below a designated threshold (typically under 30 Ω30\ \Omega to 50 Ω50\ \Omega).

Key Concept

Multimeter continuity mode detects complete electrical paths by measuring near-zero resistance and emitting an audible tone.
Estimated Time:45s
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Topics

Multimeter: Resistance and Continuity

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