I'm aware that in some situations TO92 transistors marked C556 mean BC556 (not 2SC556), can the same be for BF...? I have a board with dozens of BF422, HV transistors on. These agree with the schematic but someone has previously replaced 2 with a pair marked F422 and one of them has failed B-C-E short. Diode testing (Vb-c < Vb-e) the remaining one shows correct pinout for BF422
TO92 marked F422 = BF422 ?
Jul 24, 2010
2 Replies
That marking style is fairly common.
BC556
I don't remember coming across it before for BF... , a few times I've seen it with Philips TO92 BC... types
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