What are the encapsulations of the transistors?
Encapsulates are the different shapes and sizes that are used to protect the internal materials of a transistor, these presentations depend a lot on which application the transistor is going to be used for either power or signal treatment, there is currently an easy way to identify What type of transistor is being used, it is only a matter of locating the code that is printed and searching the internet to find all the data related to that model.
Although there is a great variety in terms of encapsulations, we can classify them in two ways: metallic and plastic, since there are many models that are almost identical and the only thing that changes is their working capacity.
The main characteristics of the metallic encapsulates are to be able to work with high powers, among the types that have the greatest range are the TO-3, TO-36, and TO-66. There is also the possibility of placing several transistors in the same package, such as the TO-8, and finally, we find those that are designed to be used as signal amplifiers with a higher power: TO-5, TO-18, TO-39, TO-46, TO-52, and TO-72.
Regarding shape, they are practically the same as the squares that use plastic, only in this presentation they are metallic and they are completely sealed to protect the semiconductors from humidity and external agents since they are completely metal, they achieve greater heat dissipation compared to of plastic.
Despite the fact that these types of packages are the ones that can handle the least, they are the most popular since they are the cheapest and can be used to amplify small signals or as switches. The most popular and most used are half-circle ones such as the TO-92 or TO-226, but when the power exceeds the former, it is passed to those with a square shape, since these can handle greater power thanks to the You can put a heat sink on the tab they have (TO-126, TO-202, TO-218, and TO-220).
With the advancement of technology, smaller and smaller encapsulations can be created, this benefits circuit makers as they can reduce the size of their printed boards using these devices called SMDs.