From: John Dyson
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Subject: Re: Transistors circuits by the thousands
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Date: Fri, 03 Jan 2003 01:53:52 -0500
NNTP-Posting-Date: Fri, 03 Jan 2003 01:45:25 EST
J M Noeding wrote:
> On Fri, 03 Jan 2003 00:49:32 GMT, Robert Baer
> > There are hundreds of similar transistor types that would work, just
> >pick those with minimum beta that you want.
> > Most small signal parts have similar quantity prices, but it is
> >relatively easy to find a part that matches or exceeds your specs.
> is it still something like Poly-Pak? You could buy small-signal
> devices with even lower beta than 50
Geesh, nowadays with transistor prices of $0.015 to $0.05 (perhaps
slightly more for a special part), the need for buying semiconductors
from places like Poly-Pak is nil (IMO.) There is still alot of
value in buying other kinds of surplus devices (mica caps or sumsuch),
For my hobby purposes, I have placed orders for 1000-5000 of the
cheaper parts (e.g. 2N3904), and perhaps 25-50 of the more pricy
parts (e.g. ATF54143.) What value is there in a pack of 100 U-test-em
of unmarked NPNs for $1, when you can purchase 100 real, marked
parts for $3-$4 (assuming minimum orders are met?) For the
very special applications (input stages, or driver/output stages),
then it isn't that big a deal to spend a little more in those
When I was a kid in the 1960s, I wasted alot of time on defective
U-test-ems than I ever gained by getting my transistors cheaply,
rather than paying $0.50-$1.00 each back then. Luckly also,
we did have a local surplus outlet that had packs of good parts
(e.g. 10-25 transistors) for reasonable price...
The idea of a cost competitive U-test-em is almost imponderable
nowadays: imagine a pack of 10000 random bipolar transistors,
in both TO92 and SMT packages :-). The price for the 'pack'
would be $10, but would take alot more money in that (assuming
the lowest burger joint labor rates) of any of our free time to
qualify the components.
Even more 'entertaining': imagine a pack of 50 random microwave
fets, U-test-em :-). Oops -- some might be missing their protective
pakaging (they are tossed into a sandwich bag for distribution :-)).