Transistor identification and similarities.

[Velvet Leopard]

Hewwo. I am in need of buying a bunch of transistors and other components for some upcoming projects, but I do not know exactly how to recognize transistors. Are all NPN transistors alike? Are all PNP transistors alike? Do the numbers on the case mean alot or are they just model or make numbers? I know where I can get transistors, but I need to know if they are compatable with the ones I have/need. I would love to know for sure so I can get the correct kind of transistors. Thankies.

 

[Exo]

There are thousends of diffirect types of transistors. The number printed on them is usually the type number, not the make.

Diffirences between them are maximum voltage, maximum current, Hfe (amplification), package, size, power, speed, ... and many other things.

Though, for general applications there are some well known types wich have been around for ages and used by everyone. For small signals types like BC547 (NPN) and BC557 (PNP) are very common (europe).
... guess you will have to have an idea of what there going to be used for before you go buy them

 

[mozikluv]

transistor compatibility

hi,

when you say "if they are compatible with what i have/need" does that mean "replacement"? if it is, then a PNP can only be replace with a PNP with the same specs like Vceo, Ic, power disipation, hfe, frequency or a transistor with a little bit higher specs. likewise with an NPN. however this approach of replacing with not an exact specs is not always applicable.