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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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16th Jan 2018, 7:38 pm | #1 |
Heptode
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 647
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What voltage rating are these caps please?
These capacitors were amongst a load of mixed components that I bought recently. I have a couple of physically identical resistors that are helpfully marked " High Voltage Resistor" but these are definitely caps and the only markings are the ones that you can see in the photos.
Does anybody know what rating these things are please? TIA, Hugh |
17th Jan 2018, 8:41 am | #2 |
Banned
Join Date: Dec 2013
Location: Middlewich, Cheshire, UK. & Winter in the Philippines.
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Re: What voltage rating are these caps please?
No. But I would be very charry about using them unless you test them very thoroughly, to the extent of destruction testing several to try to establish a working voltage. Even then I would only use them in a very non critical application, like a transistor radio.
NOS and suspect caps are really not the best thing to use, anywhere. My small stock of acquired NOS caps get checked before use but any that have odd markings or no voltage etc. get binned. What is the origin of them, they look very odd? |
17th Jan 2018, 10:46 am | #3 |
Octode
Join Date: Aug 2003
Location: Welwyn Garden City, Herts. UK.
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Re: What voltage rating are these caps please?
I think they are resistors possibly 5 watts
What makes you think they are caps? |
17th Jan 2018, 11:32 am | #4 |
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Re: What voltage rating are these caps please?
They do look resistorish. Some are marked JR, some JS. Values 470 & 820
Too flakey to consider? |
17th Jan 2018, 11:34 am | #5 |
Moderator
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Re: What voltage rating are these caps please?
The OP has nearly 400 posts to his name. I would assume he's checked them with an ohmmeter and found them open circuit, suggesting they're capacitors?
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17th Jan 2018, 11:40 am | #6 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
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Re: What voltage rating are these caps please?
What are the capacitance values (by measurement) and the dimensions?
Capacitance value relative to dimensions might give a rough idea. Lawrence. |
17th Jan 2018, 11:40 am | #7 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
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Re: What voltage rating are these caps please?
I have vague memories of caps that looked like that from when I was a B.O.T apprentice at Bletchley. I think they must have been fairly old even then (67 / 68) as they were in a load of surplus ministry junk given to us to play about with. I always assumed they were an early ceramic type but I could easily be wrong.
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17th Jan 2018, 12:31 pm | #8 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
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Re: What voltage rating are these caps please?
They look very much like typical examples of the silvered ceramic rod type capacitors that abounded in electronics from about just post-war until at least the '70s, available in a wide range of values from fractional-pf to low tens of nF and a wide range of temperature coefficients- in other words, the sort of duties that disc ceramics subsequently took on. ISTR they were made by Erie (amongst others?) and this would tie in with the outer ceramic body that was also used for their resistors- though the capacitors had a rather better reputation. Anyone who's worked on ex-military kit (in particular) will have seen lots of these- although the labelling is usually bolder and more explicit. One thing that seemed to be elusive with them was the voltage rating, I don't recall seeing this on any. There were different sizes in similar capacitance, though.
If there was a time-warp machine, I'd hoover up as many NOS as I could, classic vintage components. A typical shot of a typical application in a typical radio.... Late edit- a peek through a few equipment component lists shows many Erie Ceramicons descibed as 500V DC working, a few at 750V DC working-perhaps the bigger ones? Nothing less than 500V, possibly these being "valve era", there wasn't sufficient demand for lower voltage development. Last edited by turretslug; 17th Jan 2018 at 12:59 pm. Reason: Supplement. |
17th Jan 2018, 1:14 pm | #9 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,510
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Re: What voltage rating are these caps please?
I agree that they look like Erie Ceramicons - which is why they look like Erie resistors enclosed in a ceramic tube.
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18th Jan 2018, 7:36 am | #10 |
Dekatron
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Re: What voltage rating are these caps please?
I have come across these, I have one in a junk box somewhere, they are definitely ceramic caps. As I have a ionisation tester out on the bench I'll pop one across it, but 5 - 750v sounds about right as does Turretslugs reasoning.
Andy.
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18th Jan 2018, 12:40 pm | #11 |
Octode
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Re: What voltage rating are these caps please?
They are ceramic, there are several low pF in an Ekco televisions of the 1948-49 era.
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18th Jan 2018, 6:31 pm | #12 |
Heptode
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
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Re: What voltage rating are these caps please?
Erie Ceramicons - thanks Andy & Turretslug, that's exactly the information I was after in order to find out more.
To those who suggested they were really resistors - I made that mistake to start with too but a quick check with a multimeter (just as Graham suggested I had) showed that they weren't. Trying them on a capacitance meter confirmed that they were indeed caps and the number marked on them is the capacitance in picofarads. Hugh |