On Friday, June 22, 2012 at 8:55:37 PM UTC-4, Arfa Daily wrote:
"Piotr Piatek" wrote in message
...
On 22.06.2012 02:48, Arfa Daily wrote:
Anyone come across a transistor "D 8050" ? The logo is just a small
star. That is followed by a "D", then below that "8050". My first
thought was 2S - D8050, but that turns up no data, except the usual
component search engine dead ends and non-existent data sheets. It's a
standard TO92 D-line plastic package, and the board has its pins marked
as E-B-C.

When I see the number 8050 on a TO92 package, my first guess is an S8050:
http://www.alldatasheet.com/view.jsp?Searchword=S8050

Best regards

Piotr



Ah, yes ! Good call. With the "D" in front of the number, I hadn't even
considered that it could be an "S" prefix device, but you are right of
course. Four digit numbers in the '8000' range often are correctly prefixed
by "S". Maybe the "D" is actually part of the logo ?? I've put a piccy on
TinyPic - see my reply to spamtrap1888 for the link.

Having looked at the S8050 data, it looked a reasonable assumption that that
was indeed the type, so I put in a trusty MPSA42, which has the same pinout,
similar current rating and better voltage rating, and away it went. Control
IC then produced steady and continuous gate drive for the switching FETs,
which then produced correct and steady secondary-side voltages, so a good
result all round, and Christ knows, I needed one of those for a Friday,
after the crap week I've had ... :-)

Arfa



Except that the S8050 is a PNP and you said that yours checks out as an NPN (and you installed an NPN which works), so any data on that S8050 won't help identifying your part. I'd keep my eye on it a few days before shipping it.