What is the purpose of a time domain reflectometer?

Question

Options

• AIt uses pulses to locate and test for sheath faults, damaged conductors, loose connectors,
• BIt opens shorts and pinholes in cable shielding.
• CIt correlates the returned light pulses with a location in the fiber.
• DIt opens kinks and mismatched cable connectors.

• A
  89% (24)
• C
  7% (2)
• D
  4% (1)

Explanation

A TDR works like sonar for cables: it sends electrical pulses down a conductor and analyzes the reflections (echoes) that return when the pulse hits a fault, calculating distance to the problem based on travel time. Option A is correct because this is exactly the TDR's purpose - non-destructively locating and identifying defects such as sheath faults, damaged conductors, and loose or corroded connectors.

Why the distractors are wrong:

• B and D are wrong because a TDR is a diagnostic tool - it finds and measures faults, it does not physically repair or "open" them. No test instrument opens shorts or kinks.
• C describes an OTDR (Optical TDR), which is a related but distinct device used for fiber optic cables; it correlates reflected light pulses to locations. A standard TDR works on copper/metallic cables with electrical pulses.

Memory tip: Think of TDR as radar for cables - radar sends a radio pulse and detects where it bounces back; a TDR does the same with an electrical pulse to pinpoint exactly where a cable fault is. If the answer mentions light or fiber, that's an OTDR, not a TDR.

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