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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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19th Oct 2017, 10:38 pm | #1 |
Heptode
Join Date: Jan 2016
Location: Nottinghamshire, UK.
Posts: 676
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Capacitor voltages?
I silly question but some non electrolytic yellow poly capacitors are marked for example 630v and some 630v DC I assume these are both the same so I thought I would ask as its niggling at me!!
Cheers Kev |
19th Oct 2017, 10:45 pm | #2 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,573
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Re: Capacitor voltages?
Hi.
From my understanding the voltage rating of a capacitor is the DC rating unless otherwise marked in which case it will be marked as 400Vac for example to indicate it's AC rating. Regards Symon |
19th Oct 2017, 10:47 pm | #3 |
Heptode
Join Date: Jan 2016
Location: Nottinghamshire, UK.
Posts: 676
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Re: Capacitor voltages?
I think I have answered my own question looking at a thread on X/Y capacitors which the working voltage is AC and all others the working voltages are DC
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19th Oct 2017, 11:11 pm | #4 |
Heptode
Join Date: Jan 2016
Location: Nottinghamshire, UK.
Posts: 676
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Re: Capacitor voltages?
Thanks Symon our post crossed! Thank you for confirming that, its much appreciated
Regards Kev |
19th Oct 2017, 11:31 pm | #5 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,944
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Re: Capacitor voltages?
Yes, always assume the rating is DC unless it is clearly marked AC. The DC rating will always be higher than the AC rating.
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20th Oct 2017, 2:37 am | #6 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,199
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Re: Capacitor voltages?
Rule of thumb says: if no AC value is given, assume a factor 3 lower than the DC value (actually 2 times sqrt 2) and no high dV/dt applied unless it's a polypropylene capacitor.
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20th Oct 2017, 2:39 pm | #7 |
Heptode
Join Date: Jan 2016
Location: Nottinghamshire, UK.
Posts: 676
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Re: Capacitor voltages?
Thanks Guys much appreciated.
Kev |