On 7/10/25 04:18, andy pugh wrote:
On Thu, 10 Jul 2025 at 08:17, Erik Christiansen via Emc-users
<emc-users@lists.sourceforge.net> wrote:
(< ghesk...@shentel.net >) rakstīja:
Electrolytic caps should always be used at 90% of rated voltage or even higher
the rule for 25 year minimum service life in Telecommunications equipment was
"Never specify an electrolytic capacitor to operate above half its rated
voltage."
Which demo's that much of whats available online is published by id10t's
who have no knowledge of the chemistry involved in how an electrolytic
capacitor works. I already had 25 years of electronics troubleshooting
experience in 1972 when I walked into a Community College classroom in
Norfolk Nebraska, down with that seasons flu, of a professor who had
been teaching electronics using the NEA's std CET test as a final grade,
and who had been teaching that class for 6 years then. Allocated at 4
hours to do the test. I had to spend 15 minutes in the john because of
the flu. 125 multiple choice questions I filled out the black boxes for
and handed him the 4 sheets of paper in about an hour. He was surprised
and asked me if I was sure, I said yes so he dropped the stencil sheet
on my answers and raised his eyebrows, a sea of black, then checked the
next until he was done, I had nailed 123/125.
Later conversations disclosed I was the first to pass it at that
collage, and he had a class of 20 some taking it each year. I had seen
the notice the test was to be given the next day in the daily fishwrap,
never cracked a book as it was a just show up and pay the test fee,
$20. That test even checked my knowledge of relativity which I was
intimately familiar with at the time since I was the resident engineer
keeping a klystron powered 30kw powered UHF transmitter on the air for
the Nebraska ETV commission. Klystrons have a nasty habit of screwing
up the then NTSC signal by messing with the timing of the signal
according to the power level. And I had to educate our FCC on
relativity vs video distortion because back then we had no knowledge of
how to predistort the signal to compensate for it, now we do else
digital tv wouldn't work even with a 10kw transmitter in your shirt pocket.
That certificate, NB-118, laid on the GM's desk, has gotten me every
$dayjob since. I checked again in 1977 when I became the CE at KIVA-TV
in Farmington NM, in 6 years they were only up to 122. I have only known
of one other CET I've met over the net, but he isn't active now. Might
even have passed, its been several years since he's posted to any list
I'm on.
I thank you and several other members of this list, you're teaching has
allowed me to do stuff few even think possible. But I do think outside
of the box some. ;o)>
|"Go not to the internet for answers, for it shall say both 'yes' and 'no'"
And both can be correct, in the proper context.
Cheers, Gene Heskett, CET.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
