Free Semiconductors still available from KE6F
18 August 2016, 19July 2017, 27February 2018
Bob, KE6F, has a huge junk box that he is is willing and pleased
to share with other experimenters. Here are the items that
Bob presently offers:
BF998 Dual Gate MOSFETs. These are real
gems. He still has them. They are SMT
parts with four terminals. They are easy
to use in a breadboard and provide lots of gain and low noise
up through VHF. A 50 MHz low noise amplifier is
shown by clicking here.
To get a "pinch" of these parts, send a regular
sized (business) SASE with a "Forever" stamp to Bob and he
will send you the parts.
Incidentally,
the BF998 is not an obscure dual gate part from the
past. Rather, it is an active
component that is still listed in the Digi-Key and the
Mouser catalogs of August, 2016.
If you use these in, for example, a club project,
there is a good chance that they will still be around
for a while. (I just checked and Mouser
still has them listed in July, 2017. w7zoi)
TO-220 Power MOSFETs. The types are the BUZ101
and the BUZ104 from Siemens/Infineon. These are new leaded
parts. The specs look like these would work well for RF
power amplifiers in the low end of the HF spectrum.
Bob indicated that someone has used them for this. If
you want some of these parts, send a LARGE (8.5 x 11 inch) SASE to
Bob with a couple of dollars
of postage. Don't send money. With
the SASE Bob will send you "a fist full" of the parts in foil
wrap.
The data sheet for the
BUZ104L lists the part as 50 V max drain voltage, 17.5 A max
current, 0.1 Ohm max Rds-on, 60 Watt dissipation, and
typical gate-source threshold of 1.6 volt.
Here's what Bob, KE6F, had to say about these FETs
in a recent email:
Let your web
followers know that the BUZ104 fets came from a surplus dealer
many years back and were end of production parts from a now
extinct Silicon Valley company. BTW I'll include some
other BUZ fets in the mix BUZ 101 and BUZ 103 but I will not
be selective as I just grab a bunch from the box when I make
up the Free Bee shipments. I'm also sending some TO92
2n3904s that came from a bunch of stuff I bought from a
recycle place that got a pile of the remnants from the Grass
Valley Group closing. Once again for the power fets I
need and SASE with at least 3 bux in postage attached.
Please no cash and I can't
supply specific units; it's just a grab bag.
Our old friend Jeff, WA7MLH, has
been experimenting with the BUZ104 parts, mainly building
push-pull power amplifiers operating from a 13.5 volt
supply. He has been able to extract 40 watts, or
more, on 80 and 40 meters, with 20 dB of power
gain. Each FET is stabilized with a
drain-to-gate network consisting of 330 Ohms (3W) in series with
a 0.1 uF. The drains are protected with 38
volt Zener diodes. Each FET is separately biased.
Gain and output power drop off on 20
meters. Higher power supply voltages resulted
in broken FETs. Jeff speculates that the failures
were from gate-drain breakdown, although more measurements are
required.
And There is Even
More:
In one of Bob's
notes, he also mentioned other goodies. Here's
what he had to say: BTW
I also have zillions of 3 mm and 5 mm Red, Yellow and
Green LEDs for free along with zillions of SMT capacitors
in the 0.1 ufd and 1206 packages along with zillions of
little dual npn SMT and single NPN smts and 5 zillion
diodes smt. Please let your readers know that the
stuff is available as grab bag assortments free for the
asking with the receipt of a large envelope with three
dollars postage attached. Please no cash and paste the
stamps to the SASE.
Again, Bob emphasizes: DO NOT SEND MONEY.
The above SASE conditions apply to experimenters in the
USA. If you are elsewhere, please contact Bob
for details.
The address for the parts is
Bob Miller, KE6F
9239 Knights Lane
Wilton, CA 95693
Bob's email is millerke6f@aol.com
Many thanks Bob for your continued generosity.