Agree completely with Carl! 1N5408 diodes, mounted on perf-board, works fine.
Depending on the size of the holes in the board, one may have to slightly
enlarge them to get the thicker gauge wire of the 1N5408 through the board.
Believe it or not, Radio Shack is an excellent source of inexpensive
perf-board. Not for many things these days, except for aluminum mini-boxes and
a very few other items, but for perf-board actually true!
Glen, K9STH
Website: http://k9sth.net
On Wednesday, October 8, 2014 10:36 AM, Carl <km1h@jeremy.qozzy.com> wrote:
I wouldnt use smaller than a string of 1N5408's as they have a much higher
surge current capability as the rather obsolete 1N4007 in the era of much
higher filter cap C and dirty AC utility lines.
The diode leads are the heat sink and a minimum of 1/2" in free air is
recommended by the manufacturers. Ive no idea how potting would modify that.
My own method is to simply mount them on perf board when possible and thats
easy in the Alpha 77DX in place of the "petrified blocks".
Carl
KM1H
----- Original Message -----
From: "KA4INM radio" <ka4inm@gmail.com>
To: "amps" <amps@contesting.com>
Sent: Wednesday, October 08, 2014 9:36 AM
Subject: Re: [Amps] HV Diodes
> On 10/08/14 06:35, Chris Wilson wrote:
>
> When companies pot a string of 1N4007's (1 kV at 1 Amp) they rate the
> string at .75 Amp. The diodes, lacking the posts or copper foil to act as
> heat sinks, run hotter when potted. Short leads to the circuit board
> copper conduct heat away from the silicon die better than long leads.
>
>> Hello Han,
>>
>> On Wednesday, October 8, 2014, you wrote:
>>
>>> hi George-san and all
>>
>>> I think HV6-1 is equivalent to GI HVPR10-MX12.
>>
>>> I have measured forward voltages of these diode modules
>>> using a CVCC power supply with 100-mA current.
>>
>>> Assuming each of the diode in a string exhibits 0.7 V forward
>>> voltage one can presume how many series diodes are in
>>> the module.
>>
>>> GI HVPR10-MX12 6.36 V: 9 diodes
>>> EDHD 15k 10.67 V per a leg: 15 diodes x 2 (which I am using)
>>> SEMITECH KV-PAC SDHD-15k 12.97 V per a leg: 18 diodes x 2
>>> Toshiba S5166A (13 kV 500 mA) 14.0 V: 20 diodes
>>
>>> I think 10 x 1kV 1A diodes in series is OK as an alternative.
>>
>>> de Han JE1BMJ
>>
>> Has anyone experimented with home "potting" diode strings to make
>> their own blocks? I am curious about diode lead length, physical
>> orientation, and potting compound used. thanks.
> --
> Ron KA4INM - Youvan's corollary:
> Every action results in unwanted side effects.
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