electronic components

[dikkombe]

Hi,people i have a few questions
1-all integrated circuits perform the same work?
2-transistors are all the same work?
3-when I'm building a circuit have to choose any circuit or have to choose the specific one?
how to classify the circuits?-
thx!!!!

[Alex]

Jumping in to prevent the flames. 

1 - No, although some perform similar functions or multiple times a function.
2 - Very broadly, yes. However different characteristics between them make them useful in very different applications.
3 - You can classify circuits by their intended function, e.g. alarm system, flashlight, radio receiver, power supply etc.