DAVE: SHOCKLEY diodes  - Page 1
Forum section: electronics / general

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 10, 2021, 01:56:09 pm
content: Hi everyone,It's been quite some time since I've been able to continue my hobby in electronics (life is evolving organized chaos), and even longer since I've posted. I'm to the point where I'm clearing out what I don't absolutely need and can't fit on/under one desk.Currently, sitting in front of me on the desk, I have a small assortment of genuine Shockley diodes. (I've posted about these before, years ago.)One of them appears to me to potentially be an experimental, hand made piece. Five others may also have been experimental.Additionally, there's an assortment of:(11) 4E20 M-28(3) 4E20 A(3) 4E20-8(2) 4E20 M-8(1) 4E30 A(1) 4E40-28(4) 4E50-8(3) M4L2054(2) M4L3054(2) ST36 (The only ones with date codes - 6527)(1) ER900(1) Lettering is worn off, but what's still visible is: "STDXXX, MAL629", where XXX denotes unreadable text or space.So here goes:1) I want to see these go to people who will truly appreciate the history that comes with these pieces.2) I'd like someone who has quality photography equipment to document them, send the info to the semiconductor museum and other places of record. Curve tracer characteristics would be fantastic, too.Dave, if you're interested, I'd like to offer you the six unmarked ones and any others that you're interested in. I know that you'd handle them well and I 100% trust your judgement on wherever you would re-home them to if you didn't choose to keep them. If you are interested, PM me also, as I've got a question for you regarding these diodes.Best regards to all,Brian

author: tooki
author_rank: Super Contributor
timestamp: July 10, 2021, 02:11:15 pm
content: You should send them to Fran Blanche. She’d appreciate these far more than Dave, since he’s not really that into vintage gear. Also folks like CuriousMarc (computer history museum), etc.

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 10, 2021, 02:41:46 pm
content: I offered them to Dave already, so I'm going to give him time to respond.Depending on the outcome of that, I'm open to suggestions regarding where these should go - as long as no arguments evolve.Also, fair is fair, so if someone is going to directly financially benefit from these (selling them, building devices with them and selling the devices), I'll expect to be paid for them. I'd like to have them go to people that will educationally benefit from them and get enjoyment out of their use and history.But as I said, I'm going to wait it out for a response from Dave, and then I'll go from there.

author: Jim McAvoy
author_rank: Newbie
timestamp: March 05, 2023, 10:17:38 pm
content: Did anything ever happen with these Shockley diodes? I'd love to see some good pictures of all the different 4E20, 4E30, 4E40, and 4E50 part numbers. I found some 4E20-8 and 4E40A and 4E50A diodes, and have attached photos.

author: EEVblog
author_rank: Unknown
timestamp: March 05, 2023, 11:41:36 pm
content: Quote from: Addicted2AnalogTek on July 10, 2021, 02:41:46 pmSorry, just saw this post!I'm with Tooki, Fran Blanche might be more interested in these.But unless they have some traceable history and a story behind them, they are just some diodes I'm afraid.

author: jonpaul
author_rank: Super Contributor
timestamp: March 06, 2023, 12:22:48 am
content: bonjour à tousJust saw this now, if still available, our Foundation is,happy to accept a donation.Have,fine macro photographe and Tek 576 curve,tracer.Can document and give you the results.Eventually in a,museum of technology in EU.Please PM me if,interestingBon SoiréeJon

author: floobydust
author_rank: Super Contributor
timestamp: March 06, 2023, 01:23:15 am
content: It appears to be what's known today as a DIAC? Patent 1959US2997604(lots of complex math)edit: 4N50D $3.75ea./500-lot, in today's dollars is $39. The p/n last two digits seem to be the firing voltage. Pic from archive.org search

author: ebastler
author_rank: Super Contributor
timestamp: March 06, 2023, 12:57:23 pm
content: Gentlemen, the second post from Addicted2AnalogTek above (dated July 2021) is the last post he made on the forum so far. He has not been back (at least not logged in) since late July 2021. I'd recommend a Personal Message to him, hoping that he has email notifications turned on.