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 #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Use the MO diodes, they are perfect for this. Also my favorite diodes are the EM520, they are like 1N4007 but rated at 2kV, so you only need half of them.
Registered Member #3806
Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259
Thanks Dr. DC for your answer
I was considering using strings of 1N4007 for higher current, but when I put them alongside to MO diodes, my feeling is that these MO diodes might handle more than the 350mA they are rated
I didn't know the EM520, thanks for the tip, might be handy ;)
EDIT:
I was really curious about this so I made some destructive tests with these MO diodes
I connected one of them in series with my amp meter and a smotthing Iron on my variac
Then I increased current by 100mA steps
At 700ma it was getting barely hot
At 900ma it was getting quite hot in a few minutes
So I mounted the MO diode on a heatsink (quick and dirty mounting, just using a clamp to keep the diode pressed towards the heatsink)
Then I kept increasing current by 0.1 A steps. After each current increase I let it run for 5 minutes before pushing further
From 1A to 1.3A I could barely feel the heatsink heating.
At 1.4 A I let it run for more than 20 mins, and the heatsink was a little hot
Then I pushed it to 2 A, there it died with some smoke after one minute
Well I think these MO diodes can easilly handle 1A with a proper heatsink mounting. But I'm not sure how long they would last in such conditions
HVM12 datasheet
There is also one point on which I would like some confirmation:
I ran these tests at low voltage (betwwen 30V and 110V), so very far from the max diode voltage. Because of this I wonder if my test is reliable.
As far as I understand, the heat generated by the diode depends on the junction voltage drop and the current, and the diode voltage drop is the same at any test voltage, so the test voltage doesn't matters.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Hi, the MO diodes have a voltage drop of around 10 volts, this is why they are so big, there are many individual dies in series. Running 350 mA through them, they dissipate around 3.5 watts, which really is the limit for such a small package without heatsinking (which is the way they are really used). Some MO diodes are rated at 550 mA, but I would not go over this if you want them to last. The manufacturers have a reason to state the current they state...
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.
Which diodes for MOT full wave rectification
