The designation of the diodes. Types, marking and assignment of diodes
The designation of diodes graphic elements is a conditional indicator of the characteristics possessed by the device. At the moment there are a lot of elements, their base is diverse. Therefore, between a reduction of different maximum.
Complex graphic symbols have different diodes, including tunnel diodes, zener diodes and others. At the moment there are varieties that can resemble a discharge lamp. Moreover, such LEDs are lit, which helps a person to get confused even more in their application.
Such devices are as simple as possible, they are known to a large number of radio amateurs. There is a cylindrical base, a disk shape, diodes are marked on the legs. Tags are as clear and noticeable as possible. The color of the body is completely irrelevant. Low power will indicate low power.
If we talk about a fairly powerful diode, then we are talking about the presence of a thread under the nut. As a rule, it is necessary for mounting the radiator. For the implementation of the cooling system uses mounted elements. At the moment, the power consumption consistently drops, respectively, the dimensions of the enclosures of any device are reduced. Thanks to this you can use glass. Such material will be cheaper, stronger and much safer to use.
If we talk about the designation of diodes, then it should be said that in the first place there will be a letter or number that characterizes the material. Gallium, silicon, germanium and indium can act as such. Accordingly, the following letters (numbers) will be applied on the case: A (3), K (2), G (1), and (4). The diode characteristic will be in the second place. It must be said that, as a rule, its decoding should be viewed in the instructions. The most popular is the designation D. This means that the device is a rectifier or an impulsive type. In third place will be the number that characterizes the scope of the diode. Here numbers from 1 to 9 are used.The minimum characteristic is 1 - low frequency, which have a current below 0.3. Nine means impulsiveness, at which the carrier lifetime will be much lower than the 1 ns value. The development number can either be specified or not.
It should be noted that the denomination, which has a single digit, is always ahead of zero. For example, batch 7 will be recorded as 07. Manufacturers, as a rule, denote the group number. Thanks to it, you can learn various properties and parameters of the device. It also indicates voltage, applied current, and so on.
In addition to such diode designations, some graphical indications are also used. Thanks to them, you can solve the problem and understand how high the working point of the device is. Sometimes data on what production technology is chosen, what material is available for the body, the mass of the device are plotted on the diodes. In principle, such information will be useful to those who create the equipment; amateurs do not need such data.
It should be noted that import manufacturers work in a different way. Marking the diode of this type will be quite simple, its value can be viewed in a special table. That is why analogues will be found very easily.
Many radio amateurs know that most diodes, unfortunately, are the same person. However, it should be noted that some devices are still applied a special color marking, which allows you to immediately identify such devices. If you look at the table marking diodes, then we can say that they are divided into 2 main types. We are talking about the designation of the anode and cathode, as well as often the manufacturers replace the color of the case with an ordinary colored dot.
At first glance, you can distinguish any color diodes, which will be discussed below.
For example, diodes of the KD410 family are distinguished by the fact that they have a point in the region of the location of the anode. The case is transparent for diodes KD102. At the KD274 device, two colored rings can be seen near the cathode. It should be noted that there are also other distinguishable labels that will easily distinguish the devices from each other.
Many beginners, considering the types of diodes, unfortunately, cannot determine where the anode is, where the cathode is. It should be noted that the new devices that are being created in modern times work in such a way that the anode has a barb slightly longer than the cathode. Also, if a person can use a multimeter, he can easily distinguish the anode from the cathode.The cathode can also be found in the dark band, if we consider the sidewall of the cylinder. It is also color coded.
Foreign manufacturers have their own notation. If you need to choose an analogue, you should use the correspondence table. The rest of the characteristics of the devices from domestic do not differ. Color marking, as well as many other indications of the parameters of the diodes, as a rule, conforms either to the standards of the USA or to the European system.
Unfortunately, when creating SMD devices, they are so small that markings are often not applied. It should be noted that the characteristics of such devices practically do not depend on the dimensions.
The only thing you need to specify: dimensions affect the power dissipation. In order for a large current to pass through the circuit, it is necessary that the diode be large.
The nuances of marking SMD-diodes
If we still consider devices that have a color designation, the following types of marking should be distinguished in diodes:
In electronics, unfortunately, SMD-elements occupy about 80% of all devices.They can be superficially installed. Especially when it comes to automated builds, these devices are as convenient as possible.
It should be noted that the markings often do not correspond to the actual body fillings. When a huge batch volume is created, the manufacturer sometimes starts to cheat: the characteristics are indicated alone, and the diode works in a completely different way. Because of these inconsistencies, there can be confusion when it comes to using the device in microchips.
As for the case, here the designation of semiconductor diodes, just like the others, is unique. Four digits are indicated, which indicate the size. In general, they do not correspond to the dimensions. If you want to know about it in more detail, then you need to refer to the guests. People who do not have the ability to work with regulations as a result of any nuances can use regular reference tables.
It should be noted that the case of SMD devices from manufacturer to manufacturer may differ from each other in detail. The fact is that any manufacturer creates a base for its equipment, respectively, some details have to be changed.
Accordingly, also the dimensions of the cases of the above described SMD devices are different, they also have to fulfill other requirements for correct operation, such as the condition of heat removal and so on. Therefore, before buying, you should not only be guided by reference numbers, but also make measurements. Especially when it comes to repairing any equipment. Otherwise, such diodes may simply not be installed in the places where they are needed.
SMD device is quite difficult to install, so many beginners do not risk working with them. However, the wizard should be perfectly able to manage such electronics, as at the moment such devices are among the most popular among other types of diodes. You should also take into account the fact that when choosing devices it is necessary to look at their characteristics and external differences. Sometimes the shells are essentially the same, and the markings are different. Some symbols may not contain letters or numbers. Accordingly, it is necessary to have at hand tables that allow you to navigate in a similar issue.