Detector (disambiguation)

This article is about radio electronics. For the general use of the term detector, see Sensor. For optical detectors, see Photodetector.

In an AM radio receiver, a detector is a circuit or device that recovers the signal of interest from the modulated wave. This device is usually a diode, but in a crystal radio receiver it is the contact point between a fine wire and a crystalline material. The detector converts the (usually pre-amplified) incoming high-frequency (many kHz) AC signal into an audio-frequency signal. The latter has noise remaining, but its envelope is the required audio frequency output.