Classification of Crystal Diodes 11

14. A fast turn off (step recovery) diode is also a type of diode with a PN junction. Its structural feature is that it has a steep impurity distribution region at the PN junction boundary, forming a "self electric field". Due to the fact that PN junction conducts with minority carriers under forward bias and has charge storage effect near the PN junction, its reverse current needs to go through a "storage time" before it can reach its minimum value (reverse saturation current value). The "self electric field" of the step recovery diode shortens the storage time, quickly cuts off the reverse current, and generates rich harmonic components. By utilizing these harmonic components, comb like frequency spectrum generation circuits can be designed. Fast turn off (step recovery) diodes are used in pulse and high-order harmonic circuits.

15. Schottky Barrier Diode is a diode with Schottky characteristics and a "metal semiconductor junction". Its forward starting voltage is relatively low. In addition to materials, the metal layer can also be made of materials such as gold, molybdenum, nickel, titanium, etc. Its semiconductor materials are made of silicon or gallium arsenide, mostly N-type semiconductors. This device is conducted by majority carriers, so its reverse saturation current is much larger than that of PN junctions conducted by minority carriers. Due to the minimal storage effect of minority carriers in Schottky diodes, their frequency response is only limited by the RC time constant, making them an ideal device for high-frequency and fast switching. Its operating frequency can reach 100GHz. And MIS (metal insulator semiconductor) Schottky diodes can be used to make solar cells or light-emitting diodes.

16. Damping diodes have high reverse operating voltage and peak current, with small forward voltage drop. They are high-frequency and high-voltage rectifying diodes used in TV scanning circuits for damping and boost rectification.

17. Transient voltage suppression diode (TVP) is used to provide fast overvoltage protection for circuits. It is divided into bipolar and unipolar types, classified according to peak power (500W-5000W) and voltage (8.2V-200V).