NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

Which technology is primarily utilized by PIR occupancy sensors?

1. Infrared detection

2. Ultrasonic detection

3. Visible light detection

4. Radio wave detection

The correct answer is: Infrared detection

PIR (Passive Infrared) occupancy sensors primarily utilize infrared detection technology. These sensors work by sensing the infrared radiation, or heat, emitted by objects in their field of view, typically warm bodies like humans or animals. When a person enters the detection zone, the sensor detects the change in infrared levels and triggers the connected lighting or device. The mechanism of PIR sensors relies on the principle that warm bodies heat the surrounding air. Infrared detectors within the sensor compare the infrared energy from the environment with that of the detected moving object. Once the sensor registers the change in heat patterns, it signals to activate the lights or other connected systems. This choice stands out due to its specific application in detecting motion through heat, unlike other options such as ultrasonic detection, which uses sound waves, and visible light detection, which would rely on light levels rather than temperature changes. Radio wave detection, while applicable in some sensing technologies, does not pertain to PIR technology specifically.