ESA Certified Alarm Technician Practice Exam

The pattern that a PIR sees is determined by the properties of which component?

1. Transducer

2. Amplifier

3. Optics

4. Sensor

The correct answer is: Optics

The pattern that a Passive Infrared (PIR) sensor detects is largely determined by the properties of the optics used in the device. The optics focus and direct infrared radiation onto the sensor element, enabling the device to effectively detect changes in heat or thermal energy from objects within its field of view. Different designs and materials of the optics can alter the detection pattern, influencing how sensitive the PIR is to movement and the specific area it covers. For instance, the lens design can create zones of detection, allowing the PIR to distinguish between movement in certain areas versus others. In contrast, while components like transducers, amplifiers, and sensors play essential roles in the functioning of the PIR, they do not define the detection pattern itself. The transducer converts the infrared signal into an electrical signal, the amplifier boosts the electrical signal for processing, and the sensor is the part that responds to changes in infrared radiation. However, it is the optics that ultimately shape how and where the device can detect those changes.