A non-linear junction detector is capable of detecting

A Non-Linear Junction Detector (NLJD) is a specialized security tool used to detect hidden electronic devices. It works by transmitting a high-frequency radio signal and receiving the harmonic frequencies returned from non-linear junctions. These junctions are a fundamental property of semiconductors, which are present in all modern electronic components like transistors, diodes, and integrated circuits.

• Option A is correct: NLJDs can detect electronic circuitry (e.g., bugs, hidden cameras, or IED triggers) regardless of whether the device is powered on, off, or even hard-wired.
• Options B and C are incorrect: NLJDs do not detect the chemical compounds of explosives. Detection of conventional, plastic, or liquid explosives requires different technologies like Ion Mobility Spectrometry (IMS), X-ray scanners, or vapor detectors.