There are several types of diodes classified according to their applications

There are several types of diodes classified according to their applications:

1. Rectifier diode

In principle, the DC output obtained from the input AC is rectified. The output current greater than 100mA is usually referred to as rectification, with the magnitude of the rectified current (100mA) as the boundary. Surface junction type, operating frequency less than KHz, with a maximum reverse voltage ranging from 25 volts to 3000 volts divided into 22 levels A to X. The classification is as follows: ① 2CZ type silicon semiconductor rectifier diode, ② QL type silicon bridge rectifier, ③ 2CLG type used for high voltage silicon stack working frequency of nearly 100KHz in televisions.

2. Switching diodes

There are logic operations used at low currents (around 10mA) and switch diodes for magnetic core excitation used at several hundred milliamps. Low current switching diodes usually include point contact and key type diodes, as well as silicon diffusion type, table type, and planar type diodes that may still operate at high temperatures. The specialty of switch diodes is their fast switching speed. The switching time of Schottky diodes is extremely short, making them ideal switching diodes. 2AK type point contact is used for medium speed switch circuits; 2CK type planar contact is used for high-speed switch circuits; Used for circuits such as switches, limiters, clamps, or detectors; Schottky (SBD) silicon high current switch has low forward voltage drop, fast speed, and high efficiency.

3 . Zener diode

It is a product that replaces voltage regulator electronic diodes. Made into a diffusion type or alloy type of silicon. It is a diode with a sudden change in reverse breakdown characteristic curve. Made for use as control voltage and standard voltage. The terminal voltage (also known as Zener voltage) of a diode during operation ranges from around 3V to 150V, and can be divided into many levels every 10%. In terms of power, there are also products ranging from 200mW to over 100W. Working in reverse breakdown state, made of silicon material, with a small dynamic resistance RZ, generally 2CW type; Connecting two complementary diodes in reverse series to reduce the temperature coefficient is a 2DW type.

4. PIN diode is a crystal diode constructed by sandwiching a layer of intrinsic semiconductor (or semiconductor with low concentration impurities) between the P and N regions. The 'I' in PIN is an English abbreviation for 'intrinsic' meaning. When its operating frequency exceeds 100MHz, due to the storage effect of minority carriers and the transit time effect in the "intrinsic" layer, the diode loses its rectification function and becomes an impedance element, and its impedance value changes with the bias voltage. In zero bias or DC reverse bias, the impedance of the "intrinsic" region is very high; During DC forward bias, due to carrier injection into the "intrinsic" region, the "intrinsic" region exhibits a low impedance state. Therefore, PIN diodes can be used as variable impedance components. It is often used in high-frequency switches (i.e. microwave switches), phase shifting, modulation, limiting and other circuits.

5. Schottky Barrier Diode

It 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.

6. Transient voltage suppression diode

TVP diode provides fast overvoltage protection for circuits, divided into bipolar and unipolar types, classified according to peak power (500W-5000W) and voltage (8.2V-200V).

7. Double base diode (single junction transistor)

A three terminal negative resistance device with two bases and one emitter, used in relaxation oscillation circuits and timed voltage readout circuits, has the advantages of easy frequency adjustment and good temperature stability.

8. Silicon power switch diode

Silicon power switch diodes have the ability to conduct and cut off at high speeds. It is mainly used in high-power switching or voltage stabilization circuits, DC converters, high-speed motor speed regulation, and high-frequency rectification and freewheeling clamping in drive circuits. It has the advantages of soft recovery characteristics and strong overload capacity, and is widely used in computer, radar power supply, stepper motor speed regulation, and other fields.