Hello Win,
Yes, that's what I had in mind. They're pretty expensive
nowadays, but we maintain a full inventory: It's a little
surprising how much of my work relies on using them.
When I was a kid I scavenged lots of parts, including resistors, from
tube sets put out on the curb on bulk waste days. In Europe they used to
have those several times a year and it's a field day for "scavengers"
like I used to be. Finding a tuner with two AF239 felt like finding a
gold nugget. But I also kept all these resistors to this day. In terms
of stability not much beats a carbon resistor that has aged for 50 years.
Keeping this old stuff has saved the bacon a few times. When 1.35V
mercury batteries were outlawed a Ge diode was about the only device
that allowed retooling a camera to 1.55V cells. The alternative would
have been an expensive 2-3 point re-alignment at a specialty shop.
Welwyn (now a part of TT electronics, like IRC) also has good
pulse-withstanding chip resistors, with good data, as does IRC
for that matter.
Thanks! Good to know.
SFAICT the reduction in MOSFET Ciss for a given current-handling
capability amounts to only about a factor two over the years, or
maybe a bit more in some special cases. Or are you thinking of
a reduction in the gate-drive voltage, with logic-level MOSFETs?
Actually both. But it was more than that. In the 80's we had to make do
with a rather small selection. Very little granularity which meant we
often had to select a FET that was way too large but the next smaller
one would have caused field failures. HV BJTs weren't an option because
they ony made them for specific markets and the video transistors that
could stomach the voltage were just a wee bit too slow.
Today's FET selection feels like the all-you-can-eat buffet at Sizzler's.
