Welcome
Username or Email:

Password:


Missing Code




[ ]
[ ]
Online
  • Guests: 25
  • Members: 0
  • Newest Member: omjtest
  • Most ever online: 396
    Guests: 396, Members: 0 on 12 Jan : 12:51
Members Birthdays:
No birthdays today

Next birthdays
11/29 Sonic (58)
11/29 kamelryttarn (46)
11/30 arnsfelt (45)
Contact
If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.


Special Thanks To:
  • Aaron Holmes
  • Aaron Wheeler
  • Adam Horden
  • Alan Scrimgeour
  • Andre
  • Andrew Haynes
  • Anonymous000
  • asabase
  • Austin Weil
  • barney
  • Barry
  • Bert Hickman
  • Bill Kukowski
  • Blitzorn
  • Brandon Paradelas
  • Bruce Bowling
  • BubeeMike
  • Byong Park
  • Cesiumsponge
  • Chris F.
  • Chris Hooper
  • Corey Worthington
  • Derek Woodroffe
  • Dalus
  • Dan Strother
  • Daniel Davis
  • Daniel Uhrenholt
  • datasheetarchive
  • Dave Billington
  • Dave Marshall
  • David F.
  • Dennis Rogers
  • drelectrix
  • Dr. John Gudenas
  • Dr. Spark
  • E.TexasTesla
  • eastvoltresearch
  • Eirik Taylor
  • Erik Dyakov
  • Erlend^SE
  • Finn Hammer
  • Firebug24k
  • GalliumMan
  • Gary Peterson
  • George Slade
  • GhostNull
  • Gordon Mcknight
  • Graham Armitage
  • Grant
  • GreySoul
  • Henry H
  • IamSmooth
  • In memory of Leo Powning
  • Jacob Cash
  • James Howells
  • James Pawson
  • Jeff Greenfield
  • Jeff Thomas
  • Jesse Frost
  • Jim Mitchell
  • jlr134
  • Joe Mastroianni
  • John Forcina
  • John Oberg
  • John Willcutt
  • Jon Newcomb
  • klugesmith
  • Leslie Wright
  • Lutz Hoffman
  • Mads Barnkob
  • Martin King
  • Mats Karlsson
  • Matt Gibson
  • Matthew Guidry
  • mbd
  • Michael D'Angelo
  • Mikkel
  • mileswaldron
  • mister_rf
  • Neil Foster
  • Nick de Smith
  • Nick Soroka
  • nicklenorp
  • Nik
  • Norman Stanley
  • Patrick Coleman
  • Paul Brodie
  • Paul Jordan
  • Paul Montgomery
  • Ped
  • Peter Krogen
  • Peter Terren
  • PhilGood
  • Richard Feldman
  • Robert Bush
  • Royce Bailey
  • Scott Fusare
  • Scott Newman
  • smiffy
  • Stella
  • Steven Busic
  • Steve Conner
  • Steve Jones
  • Steve Ward
  • Sulaiman
  • Thomas Coyle
  • Thomas A. Wallace
  • Thomas W
  • Timo
  • Torch
  • Ulf Jonsson
  • vasil
  • Vaxian
  • vladi mazzilli
  • wastehl
  • Weston
  • William Kim
  • William N.
  • William Stehl
  • Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Forums
4hv.org :: Forums :: High Voltage
« Previous topic | Next topic »   

DC voltage for an AC rated capacitor

Move Thread LAN_403
Signification
Fri Feb 27 2015, 01:22AM Print
Signification Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367
I am looking for -reliable- information concerning a safe DC voltage rating for AC capacitors.
Mostly, I have seen the V*1.414 rule, or [ V x sqrt (2) ]. This is obtained, obviously, from calculating the peak value an AC signal would apply to the capacitor. So I guess there is also a peak-to-peak rule [2V*sqrt(2)] out there too.

Here are some additional comments I have run into:

The "simple textbook equation" says that an AC capacitor can take
1.414 times its AC rating with DC. However, due to AC causing extra
stress to capacitors, the real-world factor is higher.

"I have seen a few capacitors with an AC rating of 1 kV and a DC rating
of 3 kV. I have seen a few others with the factor being around 2.5."

"I think it's generally reasonably safe to have DC voltage at 2 times
the AC voltage rating, and generally only mildly adventurous to have DC
at 2.5 times the AC rating."
Back to top
Sulaiman
Fri Feb 27 2015, 02:58AM
Sulaiman Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
for foil/film capacitors I have noticed rated Vac = 0.4 x Vdc quite common
and Vtest = 1.5 x Vdc rated, but it is better to look at manufacturers datasheet,
and wiser to not use any component at maximum rated value !
Back to top
dexter
Fri Feb 27 2015, 06:45AM
dexter Registered Member #42796 Joined: Mon Jan 13 2014, 06:34PM
Location:
Posts: 195
the AC rating is sometimes lower than 1.41 due to dielectric looses

Back to top
Signification
Fri Feb 27 2015, 09:12AM
Signification Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367
So, are you saying there are some capacitors with a LOWER DC rating compared to it's AC rating?
Back to top

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob

Go to:

Powered by e107 Forum System
 
Legal Information
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.