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.
Okay, I've been trying to figure out what this cap is (I got a pile of them as surplus). I was told they're a film cap of some sort, though whether mylar or polypropylene I can't be sure. The entire marking is thus:
PH 822H 1250VHOV
I can't make heads or tails of the "PH" of "HOV" ("high over-voltage"? I dunno . . . may be "H0V") designations, as they don't fit with any references I've found. I'm assuming "PH" is a dielectric code, but . . . eh. Anyone have an idea? I mean, I could always wire them up and see how long they last, but I'd rather save them for what they're suited for if they're not going to take the beating from a TC.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I'd say it's 8200 pF (8.2nF, code 822=8,2, and 2 zeroes in pF) 1250 Volts no idea what HOV means
I think it's a multi-layer ceramic capacitor with a very high "K" dielectric which means high capacity per volume but very lossy at high frequencies.
ok for dc and low-frequency use ... e.g. cockroft-walton voltage multiplier not very good for Tesla Coils etc. ... they will overheat quickly and give poor performance.
You sure? I've not seen +/-3% multilayer ceramics. I'm fairly sure they're (as sold) a film cap of some sort. However, if they are just mylar, they're relegated to a CW regardless . . . (Large ceramics usually have standard dielectric codes printed on them anyway.)
Obviously, for my purposes, I'm hoping it is MKP! *grin* Given that the dielectric code is either a mystery ("PH"), or not listed (if "PH" refers to something else), is there anything in the way of a test I could run, short of putting them in the MMC and using it until it overheats/blows? I don't have my TC out here . . . I've recently moved across the country, so I'm putting together a new one (of course!): so I have no way to stress-test them in a working coil at present.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
well, I've pulled a cap that looks awfully similar to yours from an old TV.. It was used as a snubber for the HOT, where it sees 15kHz at 1500Vp-p, so I guess it should be quite a quality cap
Well, according to my handy-dandy pica-stick with decimal inches (Yay for art supply stores! I'll bet they never thought it'd get used for HV electronics!), it's an inch wide, just about 0.6" tall, and around a quarter inch thick at the center.
I am going to hacksaw one . . . (note to self: buy new hacksaw blades) . . . however, I've never compared MKP to MKT in section . . . do they identifiably different?
I think I'll set them aside for an MMC anyway . . . the worst that can happen is they'd overhead, and I'm just feeding this with an OBIT I picked up from an estate sale, so I can't have too terribly long of runtimes anyway.
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.