here's the annotated cross section of the 1N914 diode. the two Dumet slugs are separate pieces of metal from the leads, and are brazed together during manufacture.pic.twitter.com/F9A8gcv1aS
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here's the annotated cross section of the 1N914 diode. the two Dumet slugs are separate pieces of metal from the leads, and are brazed together during manufacture.pic.twitter.com/F9A8gcv1aS
look at the slug on the left--you may notice it has a taper at the end. i think this end is inserted last, pushing up against the ohmic contact (dot) that's already plated onto the silicon die. then when it is heated to bond the glass to the dumet, it alloys with the contact.
how does the dot get there? there's a plating bath that applies an AC voltage that's slightly above the diode's voltage rating. only the good diodes get a dot at the cathode end. bad ones break down and plate on both sides. this means they are heavier...
...to sort out the bad diodes from the good ones, they dump the whole lot into a very dense fluid. the bad diodes sink, and the good ones float, so they just scrape those off and use them. forget what fluid they use, it's apparently quite toxic. barium something-or-other?
the sleeves start out with one slug already installed. these all go into special trays. the diode chips are dumped across the tray which is then vibrated at a very specific frequency, causing the diodes to land dot side up!
(source: friend of mine who used to be involved with diode manufacturing way back in the day)
Amazing! I'd have thought the glass envelope would be too brittle to cut. How did you do it? Or perhaps you just lapped the whole thing down until it was cut in half...
the latter, i just used sandpaper.
SOMEONE got a new @dremel tool...
i've had mine for over 20 years.
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