How to distinguish the types and models of diodes?

Types of diodes:

1. Rectifier diode Using the unidirectional conductivity of the diode, the alternating current with alternating direction can be converted into pulsed direct current in a single direction.

2. The resistance of the switching element diode is very small under the action of forward voltage and is in the on-on state, which is equivalent to a switch-on; Under the action of the reverse voltage, the resistance is very large, and it is in a cut-off state, like an open switch. Using the switching characteristics of diodes, various logic circuits can be composed.

3. After the limiting element diode is turned on forward, its forward voltage drop basically remains unchanged (silicon tube, germanium tube. This feature can be used as a limiting element in the circuit to limit the signal amplitude within a certain range.

4. The relay diode plays a relay role in the inductance of the switching power supply and the inductive load such as the relay.

5. The detector diode plays the role of detector in the radio.

6. Varactor diode is used in the high-frequency head of the TV.

7. Display elements are used on VCD, ***, calculator and other displays.

8. The reverse breakdown voltage of the voltage regulator diode is constant and can be recovered after breakdown, and the voltage stabilization circuit can be realized by using this feature.

Generally speaking, it is not easy to distinguish, such as in4007, in4118, one is rectifier, one is a switch, generally remember the commonly used models, and then check the others, generally speaking, some commonly used models such as in series, but special ones have to be checked, different manufacturers, different models, basically no specific books, you can check the Internet.

The difference between the second and first stage of the pipeline is mainly reflected in the following aspects:

1.Scale: The second stage of the pipeline is usually larger than the first pipeline, including the length and diameter of the pipeline.

2.Bearing capacity: The carrying capacity of the second stage of the pipeline is higher and can transport a larger amount of fluid or gas. Primary pipelines generally carry small-scale transportation tasks.

3.Pressure Rating: The second stage of the pipeline has a higher pressure rating and is able to withstand greater pressure. Whereas, the pressure level of the primary pipeline is lower.

4.Scope of application: The secondary pipeline is mainly used to transport a large number of fluids or gases, and is widely used in oil, natural gas, chemical and other industries; The first-class spike air pipeline is suitable for some small-scale transportation tasks, such as household tap water pipelines.

In general, the second-level pipeline is more advanced and complex than the first-class pipeline in terms of scale, bearing capacity, pressure level and other high and simple aspects.

The differences are as follows: 1. The quality is different: the higher the level, the higher the welding quality requirements for the welder, and the quality of the second level is higher than that of the first level.

2. The process is different: if the first-level shooting is unqualified, the second-level shooting needs to be replaced, which is relatively more troublesome.

3. Different accuracy: the results of the second level are more detailed and accurate. Generally speaking, in the cracking, Yuan Lu determines whether he is qualified or unqualified at one time, but there are also those who choose to shoot multiple times.

Extended Information: Levels of Pressure Piping.

The long-distance pipeline is classified as GA, and the level is divided into:

The long-distance pipeline that meets one of the conditions of the Xiajian Mountain Column is GA1 level

1) Long-distance pipelines that transport toxic, flammable and explosive gas mediums with a maximum working pressure greater than that;

2) Long-distance pipelines that convey toxic, flammable and explosive liquid media, with a maximum working pressure greater than or equal to, and a conveying distance (referring to the length of the pipeline used to transport commodity media between the origin, storage and users) of 200km.

Long-distance pipelines other than GA1 are GA2.

Utility pipes are GB-class, and the levels are divided into:

GB1, gas pipelines;

GB2, thermal pipes.

Semiconductor diodes, also known as crystal diodes, referred to as diodes, in addition, there are early vacuum electron diodes; It is an electronic device that conducts current in one direction. Inside the semiconductor diode, there is a PN junction with two lead terminals, and this electronic device has the conductivity of unidirectional current according to the direction of the applied voltage. Generally speaking, a crystal diode is a p-n junction interface formed by the sintering of p-type semiconductors and n-type semiconductors.

A space charge layer is formed on both sides of its interface, which constitutes a self-built electric field. When the applied voltage is equal to zero, the diffusion current caused by the concentration difference between the carriers on both sides of the p-n junction and the drift current caused by the self-created electric field are equal and are in an equilibrium state, which is also a diode characteristic under normal conditions.

The diode, unidirectional conductivity, can be energized from its forward access with a resistance of 0, and from the reverse access is equivalent to a power outage, and the resistance is infinity.

There are too many types of transistors to tell.