NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

Which of the following lamp types does not belong in the HID family?

1. Metal halide

2. High-pressure sodium

3. Halogen

4. Mercury Vapor

The correct answer is: Halogen

In the context of lighting technology, High-Intensity Discharge (HID) lamps are a category of lights that produce illumination through an electric arc between two electrodes in a gas-filled tube. The key types of HID lamps include metal halide, high-pressure sodium, and mercury vapor. Each of these types utilizes gas and operates under the principle of arc discharge, which is central to HID technology. Halogen lamps, on the other hand, do not belong to the HID family. They are a type of incandescent lighting and produce light through the heating of a filament until it glows, accompanied by a halogen gas that enhances light output and prolongs the lifespan of the lamp. This fundamental difference in how halogen lamps generate light distinguishes them from HID lamps. Understanding these distinctions is crucial for anyone training in lighting technology, as it aids in the selection and application of appropriate lighting solutions for various scenarios.