For grins and giggles I ordered 10 2N5109 parts on E-bay (from Asia). Also
ordered new ones from Mouser which I just received today, and also had one
that I purchased a long time ago from Mouser (all of my Mouser purchased
ones are marked CEN on their sides whereas the ones from Asia are
identified as being Motorola (Motorola Emblem on their top).
I built up a simple common emitter amplifier on a white plug in
experimenter board to make simple voltage gain measurements, and the Asia
parts as suspected by others do not appear to be authentic.
1) The old and new Mouser purchased 2N5109 transistors measure similar to
each other (gain within 0.8 dB at 25 MHz).
2) At 0.5 MHz the Asia transistors have slightly more gain (about +0.8
dB), but at 25 MHz the Asia transistors definitely have less gain (average
of -2.8 dB)
3) Plotting the gain versus frequency of the various transistors show the
slope of the curves are similar between my old and new Mouser purchased
2N5109's, whereas the Asia purchased 2N5109's have a much more negative
gain versus frequency slope indicating they are definitely not similar in
performance.
I requested a refund for the ones I purchased from Asia under the complaint
that they "Do Not Appear Authentic" which is one of the choices to pick
from on the E-bay refund request system and also provided my data, and the
seller very quickly refunded my purchase.
Just FYI,
Don (wd8dsb)
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