Contents
What kind of noise does an avalanche make?
Avalanche noise is a form of noise that is created when avalanche breakdown occurs. It can be used for noise generators. Avalanche noise is a form of noise that does not occur in most circuit, but can be experienced with PN junctions that are operated at the point of avalanche breakdown or close to it.
What kind of diode makes avalanche noise?
Avalanche noise is relatively limited in its generation. Zener diodes and other forms of microwave diode that use avalanche breakdown as part of the mechanism of their operation will generate this form of noise. For Zener diodes it can normally be removed quite easily by filtering.
When to use avalanche breakdown or Zener breakdown?
When Zener diodes are used, the diodes must have breakdown voltages above about 5.5 volts because diodes with voltages above this value chiefly use avalanche breakdown, below this value Zener breakdown is the chief mode.
Where does avalanche breakdown occur in a semiconductor?
Avalanche breakdown occurs in semiconductors where a very high potential gradient exists. When this occurs electrons rapidly gain momentum and may hit the crystal lattice through which they travel with such energy that they can dislodge other charge carriers creating hole electron pairs.
How is avalanche noise used in semiconductor engineering?
The intensity of the avalanche noise is usually much larger than any other noise component. Fortunately, the avalanche noise exists only in the pn junction biased with a voltage close to the breakdown voltage. The avalanche phenomenon is often used to build the noise sources.
Why are avalanche diodes used for radio frequency measurements?
Avalanche diodes generate large quantities of radio frequency noise. As a result they are widely used noise sources for RF measurements, e.g. for RF for antenna analyser bridges and also in other items such as random number generators. In these applications either avalanche diodes or even voltage regulator (Zener) diodes may be used.