Re: 12KV 750Ma diodes

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: G Hunter <dogbrain_39560@xxxxxxxxx>

Nah, not a problem.  For one thing, this is how very
high voltage commercial diodes are built--using many
smaller elements in series potted in a little brick.
This is evidenced by the high forward voltage drop of
HV diode modules.

Secondly, when forward biased, each diode in a series
string only drops about .7v.  Multiply this by your
expected max current of 750ma, that works out to a tad
more than 1/2W per diode.  A 1N4007 at room
temperature can dissipate 1/2W indefinitely.

Experience-wise, I've had longish series strings of
1N4007s last for years in tesla coil power supply
service.

Cheers,

Greg

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Mddeming@xxxxxxx
>
> In a message dated 4/9/07 2:57:58 A.M. Eastern
> Daylight Time,
> tesla@xxxxxxxxxx writes:
> Original poster: G Hunter <dogbrain_39560@xxxxxxxxx>
>
> Here's a pair of 14kv 1000ma diodes:
>
>
http://cgi.ebay.com/HV-Rectifiers-14KV-1-Amp-Set-of-2-HV-Diodes_W0QQitemZ130095517214QQihZ003QQcategoryZ48708QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
>
> You can also roll your own by soldering twelve,
> 1N4007
> diodes in series.  This will give you 12kv at 1000ma
> for under $1.
>
> Greg
>
>
> Hi Greg,
>
> Perhaps this is not a problem, but I have always
> been concerned about
> the power dissipated in long strings of small
> diodes. Even a few
> volts each, times a dozen or  more diodes, times an
> amp can generate
> some heat. This is probably why I've seen strings of
> diodes on boards
> in oil for some X-ray units. What has your
> experience been?
>
> Thanks,
> Matt D.
>
>
>
>
> ----------
> See what's free at
>
<http://www.aol.com?ncid=AOLAOF00020000000503>AOL.com.
>
>
>




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