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.
Registered Member #2794
Joined: Sat Apr 10 2010, 05:13AM
Location:
Posts: 12
Hi, this might be a stupid question!! Do the components of a voltage multiplier need to be rated for the input or the output, or do the ratings need to increase from the input to output?
Registered Member #190
Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567
The caps need to be rated for 20% more than the maximum voltage across the terminals. Each stage will see a portion of the final output. I have a doubler and each of the two caps is rated for less than the final value
Making the assumption the question is about a half wave CW multiplier, the first capacitor must be bipolar and rated for the peak applied input voltage. All other caps and all diodes must be rated for twice the peak applied input voltage. Then apply whatever safety margin people recommend, eg the 20%, which may depend on your application and the quality of the capacitors used. So for example if the input was 1KV AC and 20% fudge the first cap would need to be 1 * SQRT(2) * 1.2 = 1.7Kv and everything else would be 3.4Kv minimum.
Other multiplier designs vary. It's certainly not a stupid question, circuit diagrams are common in books and on the internet and very few give voltage ratings.
There are some advantages to using identically rated capacitors, voltage and capacity, for the whole ladder such as behavior during a fault but this is not the most efficient design for power.
Registered Member #2794
Joined: Sat Apr 10 2010, 05:13AM
Location:
Posts: 12
All right, I was going to build this quadrupler(pic). Does it remain 20% no matter how many stages? I was planning on adding 4 more stages to the quadrupler. The input would be 7500vac. I have 16 18kv rated doorknob capacitors no diodes yet.
Registered Member #3429
Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288
TACAMO wrote ...
All right, I was going to build this quadrupler(pic). Does it remain 20% no matter how many stages? I was planning on adding 4 more stages to the quadrupler. The input would be 7500vac. I have 16 18kv rated doorknob capacitors no diodes yet.
The CW multiplier is a very common circuit that's used in Dental X-ray heads (I repair them for a living) and based on my own experience, the part that fails more often than others is the very first capacitor (labeled C1 in your diagram) in the chain. I think it's because it "sees" every + and - peak of the ac waveform coming out of the transformer. All of the other caps see only one peak every N cycles, depending on how far down in the chain (or ladder) it sits. So that first cap should not only be rated for the required voltage, but it needs to be able to handle the current also. In some CW's that I've seen, the first cap in the chain is physically larger than the other caps of the same capacitance and voltage rating. I can only assume that it's larger in order to handle more current than the other caps need to handle.
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.
Voltage doubler question
