1. What is a "diode"?
A diode is a one-way door for the current. When the voltage of the anode relative to the cathode of the diode is positive, it is called "forward bias", and the forward bias voltage must be greater than the conduction voltage determined by the material of the diode itself, the diode will allow the current to pass through; On the other hand, when the polarity is opposite (also known as "reverse bias") or the forward bias voltage is less than the on-off voltage, the diode will not allow current to pass.
Basically, if you understand the PN junction, it's a lot easier to do, and inside the diode is a PN junction.
2. Two brothers of the diode
Diodes can be divided into silicon diodes and germanium diodes (" germanium zhe, third tone, I always say zhu, I'm a fool, PS: sogou input method has an advantage: if you don't know how to spell a word, first press the letter 'u', and then input the partial part of the word to find the word... It's really embarrassing not to be able to type certain words..." )
(1) silicon diode
The on-off voltage is 0.6v ~ 0.7v, which requires at least 0.6v. The cooling capacity is stronger than that of germanium diode.
(2) germanium diode
The conduction voltage is 0.2v ~ 0.3v, which requires at least 0.2v. The cooling capacity is not as good as that of the silicon diode. When the heating temperature exceeds 85 degrees, the germanium diode will fail and become unavailable.
3, diode naming
Usually, in applications, we just let the name of the diode indicate its purpose. Such as:
(1) rectifying diode: rectifying the passing large current or high voltage; Models such as 1N4001,~1N4007,1N5002,50006 5008, etc.
(2) switch diode: used as a switch, when certain conditions are met on, otherwise off; 1 n914 models such as;
(3) detection diode: signal detection; Models such as 1N4148,1N4445, 1N34A,1N67A,1N191, etc.
(4) voltage stabilized diode: this diode is also known as zener diode, the characteristic is until the critical reverse breakdown voltage has a high resistance, the resistance is very small at the breakdown point, even if the current increases, as long as the limit current value is not exceeded...
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