help id part - maybe thyristor - Page 1
Forum section: electronics / beginners

author: fxkl47BF
author_rank: Contributor
timestamp: March 26, 2023, 11:19:29 pm
content: a friend found a couple of thesehe wanted me to id them but i can't find a datasheetmy cheap little component tester calls it a thyristor

author: janoc
author_rank: Super Contributor
timestamp: March 26, 2023, 11:30:47 pm
content: Assuming that 7807 is not a date code, that looks very much like an old 7 volt fixed voltage 78xx voltage regulator. Those did come in TO-3 package.The little tester would be pretty confused by that for sure.

author: fxkl47BF
author_rank: Contributor
timestamp: March 27, 2023, 01:36:27 am
content: i looked up the numbers across the top, 108 046, and found a lot of foreign chips but no datasheeta lot of folks selling them but no description of what they're selling

author: srb1954
author_rank: Super Contributor
timestamp: March 27, 2023, 04:36:57 am
content: Quote from: janoc on March 26, 2023, 11:30:47 pmI very much doubt that it is a 7V regulator. I don't think any of the standard 3-terminal regulators came in a 7V version.THe 7807 is most likely a date code.

author: janoc
author_rank: Super Contributor
timestamp: March 27, 2023, 09:36:33 am
content: Quote from: srb1954 on March 27, 2023, 04:36:57 amNo idea why would you think so:https://www.digchip.com/datasheets/download_datasheet.php?id=6878552&part-number=LM7807-TA3-TST also used to have L7807 but it is not made anymore.LM78xx came in fixed voltages from 4.7 to 24V, in one volt steps between 5 and 12V.Granted, 7V is not very commonly used but that doesn't mean it didn't/doesn't exist.

author: shapirus
author_rank: Super Contributor
timestamp: March 27, 2023, 09:40:20 am
content: What a nice piece of history.

author: Gyro
author_rank: Super Contributor
timestamp: March 27, 2023, 09:46:04 am
content: From the general look of the package and markings, I would say that it is a 1970s vintage part, with relevant date code. The part number has the look of an in-house part code (HP or Tek for example).

author: janoc
author_rank: Super Contributor
timestamp: March 27, 2023, 09:54:53 am
content: Quote from: Gyro on March 27, 2023, 09:46:04 amThat's possible too. I would also check whether there isn't any marking on the side of the can, instead of the top. Some manufacturers did put their markings there as well ...

author: srb1954
author_rank: Super Contributor
timestamp: March 27, 2023, 09:55:41 am
content: Quote from: janoc on March 27, 2023, 09:36:33 amBack in 1978 the 7807 didn't exist. Neither did Unisonic Technologies.Please produce produce a datasheet dated 1978 or earlier showing a 7807 in a TO-3 package to support your claim.

author: wraper
author_rank: Unknown
timestamp: March 27, 2023, 09:57:32 am
content: Seems to be Branson Ultrasonics part numberhttps://ultrasonicweldingparts.com/products/108-046f-branson-transistor?pr_prod_strat=use_description&pr_rec_id=a616c2bb1&pr_rec_pid=8138105717027&pr_ref_pid=8138105815331&pr_seq=uniform

author: gamalot
author_rank: Super Contributor
timestamp: March 27, 2023, 11:32:52 am
content: All I can find is that all Chinese sellers claim this is a high power transistor for ultrasonic welding equipment, and one of them mentions Branson 8700.

author: fxkl47BF
author_rank: Contributor
timestamp: March 27, 2023, 03:27:34 pm
content: Quote from: gamalot on March 27, 2023, 11:32:52 amthat's all i could findno mention of specs

author: janoc
author_rank: Super Contributor
timestamp: March 27, 2023, 10:15:01 pm
content: Quote from: srb1954 on March 27, 2023, 09:55:41 amSorry but I am really not going to spend hours now to dig through old catalogs for you. These things aren't all available online and pretty much everyone and their grandma made copies of 78xx regulators in TO-3 cans. Even in the Eastern bloc - I still have some MA7805s made by Czechoslovak Tesla around.If it is actually a 7807 regulator it obviously wasn't made in 1978 because then that would be the part number and not date code.I also never claimed it was an Unisonic part, only that 7V versions of the 78xx regulators do exist. The can has an obvious RCA logo, as far as I can see.If it was a transistor then I would assume the cheap tester would identify it as one and not claim it is a thyristor (SCR).

author: srb1954
author_rank: Super Contributor
timestamp: March 28, 2023, 07:22:56 am
content: Quote from: janoc on March 27, 2023, 10:15:01 pmYes, practically everyoneexceptRCA. Looking back through their old catalogs you find they had very little to offer in the linear power IC range and as far as I am aware they never did jelly bean chips like three terminal regulators.QuoteI checked a variety of RCA metal can devices and, inallexamples, the part number was arranged circularlyabovethe RCA logo in the 10AM to 2PM position. In the 3 to 5 position was the 4 digit date code and in the 7 to 9 position was an alpha-numeric code, which could be a mask number or manufacturing plant code. So, on an RCA marked part, there is simply no way that the 7807 code could be interpreted as a part code.QuoteIt could easily be an SCR. RCA used to make a wide range of SCRs and TRIACS, many of them in TO-3 packages.

author: Haenk
author_rank: Super Contributor
timestamp: March 28, 2023, 12:58:40 pm
content: Looking at google pictures, the 7807 is without doubt a datecode. Case closed - it's not a voltage regulator.So essentially, you could look up a 1977/78 databook and see what has been on offer - however it even might be a customer-specific production.

author: wraper
author_rank: Unknown
timestamp: March 28, 2023, 03:43:54 pm
content: IT's easy to figure out what it actually is by doing some measurements with multimeter. Of course it will not provide you specs but you'll figure out what type of part it is. Most likely it's off the shelf part but with customer specific part number, so you won't find it in databooks unless you figure out which usual part number hides under this customer specific code. As it's supposedly ultrasonics related, I expect it to be some sort of high voltage NPN transistor.

author: amyk
author_rank: Super Contributor
timestamp: March 29, 2023, 12:29:09 am
content: I found some sketchy references to it being equivalent to NTE327 180V 25A NPN.

author: fxkl47BF
author_rank: Contributor
timestamp: March 29, 2023, 06:17:43 am
content: Quote from: amyk on March 29, 2023, 12:29:09 amthanks, i'll pass along this info

author: Zero999
author_rank: Super Contributor
timestamp: March 29, 2023, 01:02:46 pm
content: Quote from: fxkl47BF on March 26, 2023, 11:19:29 pmThose circuit testors are generally fairly good. It's probably a thyristor, if it says so.Have you bench tested it to ensure it is a thyristor?

author: fxkl47BF
author_rank: Contributor
timestamp: March 29, 2023, 01:30:50 pm
content: Quote from: Zero999 on March 29, 2023, 01:02:46 pmi haven't

author: wraper
author_rank: Unknown
timestamp: March 29, 2023, 02:12:33 pm
content: IMHO instead of stupidly relying on these cheap testers everyone who deals with electronics should know how to do component measurements with multimeter. Diode mode is vary handy for testing different semiconductors. I learned how to do it when I was around 10 years old and it was one of the first things I learned.