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On 11/23/24 09:52, Nuno Yahoo wrote:

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Hang in there, I do get to glass diodes and 120V....

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I was 14 and using some glass case 1N4004 from Motorola.

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My uncle worked for Ledex and had a special run of 1N4004 made with glass so they could visually inspect the junction. They made many products but their primary product was rotary solenoids, a ~3/8"? pull in was turned into a ~90 degree movement similar to the image shown here.

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Ledex made the locking system for the LEM to Apollo command module.

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[They also modified several hundred dot matrix printers to print braille for free]

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NASA wanted Six Sigma a decade or two before Motorola came up with the idea and wanted visual inspections of the diode junction. [Don't ask why it was NASA!]

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It worked out the visual inspection was no better (and probably worse) then testing Vf at a specified current and breakdown voltage limited to a few uA for 100 hours at various temperatures.

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So I ended up with a 100 of these odd balls. They tested several hundred glass diodes to destruction, it worked out the epoxy case was much better with intense vibration, it didn't shatter like glass. [wonder how much that bit of data cost, oh wait, don't ask, it was NASA!]

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Now the silly part.

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I made a 'bridge' rectifier late one night (early one morning) and got distracted and wired all 4 diodes in series. Yes it was silly.

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Hint do not try to dig out the now gone VNG Australian time station while doing anything that requires total focus....

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Anyway I was just a tad [totally] distracted and was building a full wave, direct line powered 160V DC power supply.

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When I plugged my miswired diode 'bridge'...there was a brilliant flash of light a loud band and the lights went out.

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My room lighting was wired to the same fuse as the outlets. But my room was on a separate magnetic breaker that opened before the fuse. [wonder why Dad added that....] I had the breaker closed before my parents were there...

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Fortunately I wore regular glasses, which were ruined and Mom dug a gazillion bits of glass out of my face and dabbed each puncture with iodine.

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The worse oops I was "part of" was in EE lab when the student in the next work station discharged a ?1uf? 20kV capacitor charged to ~15kV with a 5W 100k carbon comp resistor. I saw what he was going to do, turned and started to say "Don't" but it was too late. The resistor went off like a blasting cap. It ruined my glasses and dress shirt, we had to dress up back then for school, I had a half dozen bits of carbon comp resistor in my face, about the same in both arms, the student who messed up looked like you'd shot him with bird shot, a lot of skin was just peeled away.

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He wailed for about 10 seconds before shock caused him to faint.

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{I puked from the sight.}

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The dean was unamused, we had a new lab supervisor the next day and I had a nice nurse dig out the bits.?<"Now this is going to hurt." I didn't say "Brilliant like it doesn't hurt right now!">

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The school bought me new glasses and started a rule "Safety glasses must always be worn in the lab" and issued each of us our own pair...and kicked out the next student who didn't wear their glasses, no warning just "You are expelled."

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I still have no idea what he was doing, a capacitor of that value charged to that voltage could kill.

It was a major safety violation and we had health and safety people crawling up our butts for the next month.

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They'd have had a collective heart attack if they'd visited the chemistry labs.
"Safety? We don't need safety, we have luck!"?

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In the late 80s or early 90s a professor was 'cleaning' some chemistry equipment in the engineering quadrangle, and did something wrong, the explosion blew out almost every window in the building, even those in rooms with closed doors. The professor left for greener pastures soon after. They mobilized all the physical plant workers and building operators bought up every push broom at all the Lowe's (and maybe Home Depot, don't know when they came to Lexington) in central Kentucky and spent the next 20 hours sweeping up glass.

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I worked in a building built in 1910 with walls 1 foot thick of concrete. You could feel the blast like someone hit you as hard as they could with a firm pillow. The vet who'd served in Vietnam and I dropped to the floor and rolled next to a thick wall. I thought "Unibomber or Weather Underground...wonder which...." Yea we were laughed at but if it had been an explosion closer, we'd probably have survived unhurt.

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[I went through a civil defense class where the practical consisted of a teacher popping a paper bag filled with air screaming "hit the floor!" at random intervals for 4 hours a day for a week. That made the training stuck. Anyone else remember "duck and cover"?]

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I have no idea what energetic chemicals he was using for what purpose, I suspect he was extremely luck not to be charged with a crime. [or be killed by the blast] The forces of law and order frown on unauthorized explosions. I'd liked to have been a fly on the wall when he explained what happened to the dean of the college of engineering....bet that was interesting.}?

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I've had 3 pieces of resistor work their way of my arms in the last 40 years. Freaked my wife out the first time when I said "Oh, that's just a bit of resistor."

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The oddest thing this year [so far] was a quarter inch piece of something off white about 1/2" X 1/8" came of the? healed surgical incision on my left leg during PT. It freaked the therapist out.

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They didn't sew or directly glue the incision after surgery but placed a flexible mesh over the entire length that extended an ~inch and a half on each side then applied 'glue.'

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I inspected the mesh when it came off and there were no tears or holes.?We showed it to the surgeon and he sent it to pathology, he was a bit concerned. The path report? came back "small piece of pure calcium."

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Now where in the heck did a bit of pure calcium end up just below the surface of the incision? It had to be shallow or it'd never have worked it's way out. And the spot it came from didn't bleed.

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The surgeon ordered a high resolution ultrasonic scan of the incisions on each leg, at hospital expense.

It was interesting to see the inside of the incision, how the scar tissue runs from the surface all the way down to the bone. And, it was really interesting to see the two pieces of metal that make up my new knee joint.

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[We can rebuild him. We have the technology. We can make him better than he was...."....a Dr. Pepper to the first to ID the quote...funny my replacement corneas for cataracts don't give me telescopic vision.,,,]

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So yea I've had glass diodes "light up with 120," hope to? never experience it again.

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Did I mention it was loud?? Oh lord was it loud, my ears rang for an hour.?

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[Oh...(mythical)NE-1 neon bulbs also explode when connected between a 100 foot random wire antenna and ground when lightning strikes nearby. Maybe a bit louder.....don't ask.]

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I've often wondered why my parents didn't sell me to the Gypsies..... [No insult intended for the Roma Peoples]

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Ledex was bought by Lucas and my uncle retired...I'll avoid the obligatory jokes about Lucas Lord of Darkness or why the British drink warm beer....

well at the moment aan arduino uno is driving the aod472 fets to drive a nima 23 stepper,i have made a pcb in eagle the buz 72 would be better to mount on the pcb than the d2pak fets,i just wondered if they would work,i am using 24v for the stepper.

would a buz 72a be ok for a replacement?