What is a SILISTOR ? - Page 1
Forum section: electronics / beginners

author: BravoV
author_rank: Super Contributor
timestamp: October 30, 2018, 02:11:30 am
content: Click to enlarge.Recent visit to local recycling shop, bought this, and yes, I'm a hoarder, as its dirt cheap < $3, and also never seen anything like this before, so I grabbed it.Google results don't show much, although its sort of thermistor, but I get it that it is sort of temperature sensor, cmiiw.Attached below other various angle shots with TO220 as reference size.Its 3 terminals device, and looking at the clipped wires, it must be used in industrial or big machinery, isn't it ? Or even 4 terminals (including the metal chasis mount) ?Any insight , comments about this component, or where its suitably used at will be appreciated.

author: bitseeker
author_rank: Super Contributor
timestamp: October 30, 2018, 02:31:56 am
content: Never heard nor seen one before. Silistor sounds like its resistance varies with silliness.

author: BravoV
author_rank: Super Contributor
timestamp: October 30, 2018, 02:39:42 am
content: Quote from: bitseeker on October 30, 2018, 02:31:56 amLOL, had the same thought when I saw it too.

author: ArthurDent
author_rank: Super Contributor
timestamp: October 30, 2018, 02:51:02 am
content: It looks like an old high power silicon carbide varistor (MOV)

author: xrunner
author_rank: Super Contributor
timestamp: October 30, 2018, 02:53:35 am
content: Quote from: BravoV on October 30, 2018, 02:11:30 amConnect it to one of the Chinese transistor testers it'll tell ya.

author: mtdoc
author_rank: Super Contributor
timestamp: October 30, 2018, 03:32:26 am
content: Quote from: bitseeker on October 30, 2018, 02:31:56 amBegging for an electronics version of a Monte Python sketch. The Ministry of Silly Resistors.

author: rs20
author_rank: Super Contributor
timestamp: October 30, 2018, 05:04:13 am
content: Quote from: xrunner on October 30, 2018, 02:53:35 amIt sounds like you're saying this as a joke, but very often the output of the Chinese components testers will be extremely illuminating*, and valuable to include in a thread like this, even if its guess isn't immediately correct. Unfortunately, this isn't one of those times, it'll just appear as a short circuit (assuming this thing is a 100V MOV.)* I once put a (4-terminal) optocoupler into a 3 terminal component checker, and it reported back that it was an SCR. This seemed funny and silly at first, until I realised that the configuration I had created by reducing the 4 terminals to 3 had created something that behaved very very much like an SCR (the transistor powers the LED, which sustains the light keeping the transistor on, hence the latching behaviour.)

author: daqq
author_rank: Super Contributor
timestamp: October 30, 2018, 05:59:35 am
content: If you put two in series, do you get a serioustor?

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 07:01:12 am
content: I knew this, and didn't even slightly use google (and I never joke). (ok, you had me, I hadn't heard of it either).Quotehttps://www.radio-electronics.com/info/data/resistor/thermistor/ptc-positive-temperature-coefficient.php

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 30, 2018, 09:56:02 am
content: Strange that it would have voltage and current ratings, like maybe it's a current limiting device.I don't know how old the usage is, of the silicon PTC term. This is, I guess, 60s or 70s Japanese, so it's probably hard finding references over here to begin with, let alone online...Would be strange to have a PTC, that's three terminal, and suitable for some power I would guess. It's not a polyfuse style device -- if it is a PTC, it's not that kind, but a softer slope (R roughly PTAT).Some electrical tests should tell what it is, or at least hint at it.Tim

author: BravoV
author_rank: Super Contributor
timestamp: October 30, 2018, 10:19:16 am
content: Quote from: ArthurDent on October 30, 2018, 02:51:02 amLooks really similar, but this Silistor has 3 terminals, while that MOV even has the similar 2 red discs sandwiched, still its a 2 terminals device as the outer clamping metals are connected.

author: BravoV
author_rank: Super Contributor
timestamp: October 30, 2018, 10:21:29 am
content: Quote from: T3sl4co1l on October 30, 2018, 09:56:02 amTim, any hint what or how to test ?Most thermal sensor (non active component/semiconductor) devices have only 2 terminals right ?

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 10:22:01 am
content: Quote from: T3sl4co1l on October 30, 2018, 09:56:02 amIf you look carefully at the picture, it has two terminals each. But there are apparently two of the PTC (or whatever it is) devices, sharing one terminal, common to both of them.Maybe they have different temperature settings (coefficients etc), between the two PTCs, so that it can be used to regulate the temperature of something, between two set points, or something.I.e. one temp for turn on, another temp (i.e. hysteresis between them) to turn back off again.But there are thousands of other speculative options at this point.

author: glarsson
author_rank: Frequent Contributor
timestamp: October 30, 2018, 11:50:01 am
content: Very large for a temperature sensor. Why make it this large and have to wait hours for a reading?

author: ArthurDent
author_rank: Super Contributor
timestamp: October 30, 2018, 01:07:53 pm
content: SILIcon carbide variSTOR or what we call today an MOV. These large bulk ones were first made by GE for industrial use and the smaller ones that look like an orange disc capacitor followed for use in equipment for home use. The disks could be wired in parallel for higher surge capacity like the one I showed above or could be used on a house split 240 VAC to have one from each 120 line to neutral like the 3 wire one shown in the first photo. There are large ones still used on power poles near transformers and look like tall finned insulators. Here's another photo of one with 2 leads and one with multiple connections.

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 02:21:53 pm
content: There seem to be datasheets online (not necessarily the device the OP found, but more modern ones).So Silistor seems to be a brand name.Which is a type of Varistor, if (Silistor) is a brand name, but PTC if (Silistor) is used as a generic name.https://www.datasheetarchive.com/pdf/download.php?id=cb2132fb1bb8b58e2f644ad06486a8c6dc1e4e&type=O&term=silistorThere seem to be lots of datasheets, I only looked at one of them, linked to above.https://www.datasheetarchive.com/silistor-datasheet.htmltl;drIt seems to be a MOV/Varistor. Hence the 100V/20mA values on it.

author: drussell
author_rank: Super Contributor
timestamp: October 30, 2018, 03:13:24 pm
content: I agree that theSilistoris a brand/product name, in this case apparently made byIshizuka Denshi. Ok, that makes sense, but if it is a MOV type device, what is up with the 20 mA rating specification?There are Japanese patents granted to Ishizuka Denshi for various things relating to temperature measurement like "method wherein an intermittent signal is applied to a temperature measuring part to operate a temperature detection element" and ones dealing with "thin film thermistor," "infrared detector," "infrared sensor," "production of temperature sensor," etc.Perhaps a little more digging in to what this company traditionally focused on, what their product range included, etc. would yield some likely useful information.Google Patents search for patents assigned toIshizuka Denshi KK

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 30, 2018, 03:18:12 pm
content: Quote from: BravoV on October 30, 2018, 10:21:29 amSure: just for basics, see if it has a meaningful resistance. If not, then capacitance. Test it under incrementally higher voltage/current, see if it's nonlinear. If it's looking more like a MOV, try a higher voltage supply (200V+?) with a series resistor (100k?) and see if it has a reasonable varistor voltage.I don't know what the 20mA means, but 100V is mains over in JP so it could be that it's rated by nominal AC RMS, like most (many?) MOVs are, and you should expect a Vz somewhat over 150V.Tim

author: Gyro
author_rank: Super Contributor
timestamp: October 30, 2018, 04:08:27 pm
content: Looking at the tabs, there are a pair of same colour and gauge wires clamped to each tab. That would probably support the idea of some sort of 'across the line' type usage.

author: drussell
author_rank: Super Contributor
timestamp: October 30, 2018, 05:46:40 pm
content: Quote from: Gyro on October 30, 2018, 04:08:27 pmIf it is an "across the line" device, what does the 20 mA specify?I believe it is a non-linear resistance element of some kind, but I'm not so sure it is some kind of surge supressor or spike arrestor.

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 05:51:34 pm
content: Quote from: drussell on October 30, 2018, 05:41:40 pmIf you accept that I might be a million miles out and totally wrong.When I read through a bunch of the datasheets, by that brand, the 20mA's, seems to be what we would call (in English), the maximum continuous current, for the device.Which follows through logically, because the datasheet was (for the device I was looking at), around 2.9 Watts max dissipation, at around 100 volts, hence 20 mA's doesn't sound too unreasonable.Although this might be an unexpected parameter, don't forget these are probably components from a rather long time ago, different manufacturer so does their datasheets differently.Also there are even graphs, showing the current (in mA's vs highish voltages).I'm not clear if these currents (20 mA's) are suppose to flow, because these are old non-linear resistor devices, rather than modern MOVs, or if it is unwanted leakage currents, increasing at higher voltages, because they are very old devices.Or I'm completely wrong. (Because the datasheets are rather brief and seem to be Japanese originally, I'm having partial difficulty understanding them).

author: RoGeorge
author_rank: Super Contributor
timestamp: October 30, 2018, 06:02:40 pm
content: That's 20 Mega Ampere, not 20 mili Ampere.

author: drussell
author_rank: Super Contributor
timestamp: October 30, 2018, 06:10:47 pm
content: Quote from: RoGeorge on October 30, 2018, 06:02:40 pmCould be. We should haveBravoVtest it as such.Must provide video, though...

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 06:17:33 pm
content: Quote from: RoGeorge on October 30, 2018, 06:02:40 pmYou have got to be joking!I am talking about the maximum allowable continuous currents, for a device with something like 145 volts across it and a limited maximum dissipation of something like 2.9 Watts (stated in the datasheet).20mA at 145 volts = 0.02 x 150 = 2.9 Watts.You seem to be talking about the maximum peak currents.I was seeing similar devices in the datasheets, rather than the exact one the OP has. But it is by the same manufacturer.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 30, 2018, 06:23:10 pm
content: Not joking, just mislead by the capital M, sorry.Found some datasheet.P.S. I missed a few posts, including the one with your link to the datasheet.

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 06:34:33 pm
content: Quote from: RoGeorge on October 30, 2018, 06:23:10 pmIt is all too easy to miss things in threads, no worries.You had me worried, because MOVs often do deal with extremely high PEAK currents, so I could have easily been mixed up about it.

author: MK14
author_rank: Super Contributor
timestamp: October 30, 2018, 07:18:31 pm
content: From having a quick partial read on a varistor application note.I'm wondering if they mean, 100V (limit) when a current of 20mA flows.Hence why it says 100V 20mA.So a more modern varistor, would probably be 100V at 1mA, and may just say 100V, with the datasheet going into the proper details.The app note is here:https://www.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_varistors_basic_properties_terminology_and_theory_application_note.pdfQuote