Construction Coordinator Practice Exam

What is a metallic time domain reflectometer (MTDR) primarily used for?

1. A test instrument that measures temperature variations

2. A test instrument that measures reflected voltage in metallic cables

3. A tool for measuring signal strength in fiber optics

4. A device designed for visual inspection of electrical circuits

The correct answer is: A test instrument that measures reflected voltage in metallic cables

A metallic time domain reflectometer (MTDR) is primarily used to measure reflected voltage in metallic cables. It operates by sending a pulse through the cable and analyzing the reflections that occur at various points along its length. These reflections can indicate issues such as faults, breaks, or any changes in impedance within the cable. By interpreting the time it takes for the reflected signal to return, technicians can deduce the location and nature of the problem in the cable infrastructure. The other options provided refer to different types of instruments or applications. For example, measuring temperature variations involves thermometers or thermal cameras, while measuring signal strength in fiber optics would require optical time domain reflectometers or specialized fiber optic testing equipment. Lastly, visual inspection of electrical circuits typically involves tools like multimeters or visual inspection cameras, which do not analyze reflected voltage in metallic cables. Therefore, the focus and capability of MTDR distinctly align with the measurement of reflected voltage in metallic cabling systems, making it the correct choice.