Hello

Can somebody write how works
diode with label 'N'
and diode with label 'S'

(small green)

The labels is called a "top mark" if you have a top mark directory you can get the real world part number for the diode. Then the data-sheet and all the info. But in general there are two types of protection diodes. first is Schottky the second is Zenner. The Schottky has a low forward voltage drop and is used to protect from power reversals. The Zenner has a set voltage at which it begins to conduct in reverse. This limits the maximum supply voltage. There is a third type of "Diode" that is not really a diode but a Diac. It will go from an open to a short if its brake-over voltage is exceeded.


Hope this helps

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HWHacker
Smiles

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You don't have to backup all of your files, just the ones you want to keep.

I suspect that the OP may be referring to smt fuses, not TVS diodes.

Littelfuse Surface Mount Fuses, N = 2A, S = 4A:
http://www.farnell.com/datasheets/48294.pdf