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What is a Diode Detector?

Jean Marie Asta
Jean Marie Asta

A diode detector is an electrical component that is commonly used in radio receiver circuits. These tools are also known as semiconductor diode detectors, and they regulate the passing of electrical currents. With a diode detector installed, impulses will be restricted from passing in the reverse direction, and will pass only in the forward direction.

Used to recognize the presence of signals in a circuit, detector diodes are common in the field of radio broadcasting. They are known for their simplicity and efficiency, and their uni-directionality is used for controlling direct currents. As diode detectors block reverse direction currents, they can change alternating currents (moving back and forth) to direct currents (moving in one direction). This eliminates any potential problems regarding the polarity of the current.


With other types of detectors, voltage may pass through with little current in a linear detector. The non-linear diode detectors, on the other hand, are solely forward-based, and begin to conduct with any level of voltage or current. It is for this reason that they are also common in amplifiers with high output voltage levels.

The diode detector takes the incoming signals or impulses, and channels them in one direction, allowing the currents of the circuit to be controlled. Though they have lower voltages and higher sensitivities than other linear detectors, they are useful in gaining control of a circuit with high polarity impulses. These detectors are most often preceded in a circuit by a type of filter, known as a band-pass filter, which will distinguish between the types of usable frequencies. This is because the diode detector does not recognize different frequencies nor discriminate between impulse types.

Though efficient for a variety of purposes, the diode detector can produce fading problems in short wave broadcasts during radio transmission. This happens because of the non-selective nature of the diode detector. When differing signals pass through the detector during transmission, the path lengths tend to vary. As the signals reach the detector at different times, they may be removed entirely from the broadcast. The result will likely produce a fading or distorted sound, and can also produce odd tones.

Diode detectors are also known as peak detectors. Synchronous detectors, unlike diode detectors, more reliably produce a broadcast with less distortion. Although these detectors may be more difficult to use for a simple circuit transmission, they provide a higher quality broadcast than diode detectors.

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