"Simistor"? - Page 1
Forum section: electronics / general

author: ozcar
author_rank: Frequent Contributor
timestamp: January 17, 2021, 06:46:43 pm
content: In another forum, somebody referred to an ST-made component, ACST6, as a "simistor", a term I had never heard of before. I don't feel totally ignorant though, as I note that even ST do not seem to use that name, preferring the long-winded "Overvoltage protected AC switch" -https://www.st.com/resource/en/datasheet/acst6.pdf.An old thread here hints that "simistor" could be derived from "symmetric thyristor", and by observation, Google seems to treat "simistor" as some sort of synonym of "triac", but such usage seems to be pretty rare. I also found that the term has been used for a completely different component, the "silicon thermistor" -https://www.theengineer.co.uk/silicon-thermistor/.So, if somebody were to mention "simistor" to you, would you know what they were talking about?

author: Zero999
author_rank: Super Contributor
timestamp: January 17, 2021, 07:38:59 pm
content: I've never heard of it. The data sheet is for a snubberless TRIAC. I presume it's a marketing term.

author: wraper
author_rank: Unknown
timestamp: January 17, 2021, 07:40:12 pm
content: It's a triac. Triacs are called simistor in Russian.https://ru.wikipedia.org/wiki/%D0%A1%D0%B8%D0%BC%D0%B8%D1%81%D1%82%D0%BE%D1%80

author: ColdPower
author_rank: Contributor
timestamp: January 17, 2021, 07:42:37 pm
content: When I went to school, the exact wording for triacs was "simistor" or the long version was exactly "symmetric thyristor". I guess maybe coming from Russian -https://www.google.com/search?sxsrf=ALeKk03_nn1c7UZULvVcKPkEnjoFOcwy4w%3A1610912449941&source=hp&ei=wZIEYLC1N_TTgwfxx7XQDA&q=%D1%81%D0%B8%D0%BC%D0%B8%D1%81%D1%82%D0%BE%D1%80&oq=%D1%81%D0%B8%D0%BC%D0%B8%D1%81%D1%82%D0%BE%D1%80&gs_lcp=CgZwc3ktYWIQAzIFCAAQyQMyBAgAEB4yBAgAEB4yBAgAEB4yBAgAEB4yBAgAEB4yBAgAEB4yBAgAEB4yBAgAEB4yBAgAEB46CwgAELEDEIMBEMkDOggIABCxAxCDAToICC4QsQMQgwE6AgguOgUIABCxAzoICAAQsQMQyQM6AggAOggILhDJAxCTAlDqCFjhD2CEEWgAcAB4AIABcIgB3gWSAQM2LjKYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwjwmd3C3KPuAhX06eAKHfFjDcoQ4dUDCAk&uact=5

author: ozcar
author_rank: Frequent Contributor
timestamp: January 17, 2021, 08:04:59 pm
content: Quote from: Zero999 on January 17, 2021, 07:38:59 pmI'm glad to hear I'm not the only one to be unfamiliar with it. It was not obvious that ST had used it as a marketing term, but maybe I missed that.Quote from: wraper on January 17, 2021, 07:40:12 pmI'll have to take your word that "simistor" is mentioned there, as I don't know how that would be written.

author: wraper
author_rank: Unknown
timestamp: January 17, 2021, 08:13:38 pm
content: Quote from: ozcar on January 17, 2021, 08:04:59 pmPut into google translate and let it sound.https://translate.google.com/?sl=ru&tl=en&text=%D0%A1%D0%B8%D0%BC%D0%B8%D1%81%D1%82%D0%BE%D1%80&op=translate

author: RoGeorge
author_rank: Super Contributor
timestamp: January 17, 2021, 08:53:19 pm
content: Triac.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 18, 2021, 01:32:18 am
content: Quote from: wraper on January 17, 2021, 07:40:12 pmMaybe I'm wrong, but the simisеor is not only a russian name, it is an international name for two counter-connected thyristors with a common control input. Triac has a different structure. 3Q, 4Q...

author: ozcar
author_rank: Frequent Contributor
timestamp: January 18, 2021, 02:42:00 am
content: Quote from: S. Petrukhin on January 18, 2021, 01:32:18 amIf that spelling was intentional, it defeats both Google and Bing, quite an achievment!"Semistor" ( a suggestion from Mrs Ozcar, who did a course of Russian translation half a century ago), seems more promising...

author: RoGeorge
author_rank: Super Contributor
timestamp: January 18, 2021, 08:41:27 am
content: In the datasheet linked in the OP it is described as a triachttps://www.st.com/resource/en/datasheet/acst6.pdfand it might be described as a diac with a gate (my guess), but the name of simistor is mostly unknown.

author: wraper
author_rank: Unknown
timestamp: January 18, 2021, 09:57:57 am
content: Quote from: S. Petrukhin on January 18, 2021, 01:32:18 amSuch part does not exist AFAIK and would not work to begin with. You cannot simply connect gate terminals together.

author: ColdPower
author_rank: Contributor
timestamp: January 18, 2021, 11:48:07 am
content: Quote from: wraper on January 18, 2021, 09:57:57 amIncidentally, that is the triac's "simistor" equivalent circuit, isn't it

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 18, 2021, 12:11:33 pm
content: Quote from: wraper on January 18, 2021, 09:57:57 amThere are thyristors that are controlled not relative to the cathode, but relative to the anode.

author: ozcar
author_rank: Frequent Contributor
timestamp: January 18, 2021, 04:35:16 pm
content: Quote from: wraper on January 17, 2021, 08:13:38 pmI just noticed that getting that to say "triac" results is something like "tree-ack", which is not how I say it. What next, tree-angles? So, not sure that is very trustworthy.Thanks for all the comments, I'll have to put this down as yet another of the many things I did not know. Or, if perchance I did know it, I had forgotten, an increasingly common phenomenon.

author: VK3DRB
author_rank: Super Contributor
timestamp: January 18, 2021, 10:35:19 pm
content: Quote from: Zero999 on January 17, 2021, 07:38:59 pmSIDACtor... just a TVS with a marketing term that makes it fantastic.