🔍 Key Concepts

• Halide leak detector (halide torch) construction and how it senses refrigerant leaks • Which type of detector uses a heated copper plate that changes color in the flame when halogen refrigerant is present • Differences between electronic, sonic/ultrasonic, and halide torch leak detectors as shown in the illustration

💭 Think About

• Look at each device and think about which one uses a flame and which ones are purely electronic or acoustic instruments • Ask yourself: in which of these designs would a small copper plate or coil need to be heated for a color change to occur? • Match the equipment in the picture to what you know a halide torch setup looks like from refrigeration practice

✅ Before You Answer

• Identify which option includes a gas cylinder and burner assembly, since the copper plate must be heated in a flame • Eliminate detectors that are clearly handheld electronic sensors or sound-based leak finders with headphones or large funnels • Before choosing, be sure you can describe in your own words how the copper reaction plate works in that detector type