"GregS" wrote in message
...
In article ,
(GregS) wrote:
In article , "Travis
Jordan"
wrote:
Most people would just use the NTEreplacement.
I found a distributor who claims to sell this Towers
International Transistor Selector from 1977 ??
greg
The more I read the responses, the more confused I get. There appears to be
literally hundreds of thousands of different transistors. They have various
ratings including, but not limited to:
ECO
EBO
BCO
Ic
Ib
hFE (min AND max)
Pd in Watts
Which ones need I concern myself with? The various "cross-reference" pages
all give different results when presented with search keywords. The most
confusing term I see is hFE... I consulted a catalog (digikey) to try to get
a handle on how these ratings correspond to each other, the various
packages, etc. The "hFE" rating may jump from 25 to 1000 between a "40V,
1A" and a "60V, 2A" transistor. ???
What I mean is, without getting into the meat of transistor theory and
operation (yeah, I know, I've got to go there sometime), is there a simple
way for me to pick an "equal or greater value" transistor to replace my bad
one? For example another poster suggested TIP42C as a replacement.
Here's how they stack up
Parameter 2SB527 TIP42C
V(CBO) 100 100
V(CEO) 110 100
Ic 0.8A 6A
Pd 10 10
I was all happy until I saw the hFE rating. This is a measure of
transistor's gain. There was no absolute maximum gain given for the TIP42C,
the value is "30" at 0.3A, so I'd imagine that might approach the value of
"55" given as the absolute max on the 2SB527 as Ic approaches zero on the
TIP42C.
Thanks a lot for your assistance so far, I think I'll rummage around a bit
and see if I can scare up ANY PNP power transformer rated at 100V and 1A.