Re: Converting diodes to resistors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Black Moon by way of Terry Fritz <teslalist-at-qwest-dot-net>" <black_moons-at-hotmail-dot-com>

Also note we put it across the spark gap because the spark gap is only a 
few 100v when arcing over, and it has a slow rise time otherwise.
when you put it across the cap, you get your RF ringdown feed RIGHT into 
your PSU


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Converting diodes to resistors
>Date: Sun, 22 Jun 2003 16:12:06 -0600
>
>Original poster: "Daniel Barrett by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <dbarrett1-at-austin.rr-dot-com>
>
>     Heya!
>     The diodes are highly capacitive, so the RF just caused excessive
>current flow- the diodes can only stand a few microamps. Try to use (very)
>fast recovery diodes for this. I have yet to cook a UF4007, but have burned
>up hundreds of 1N4007s...
>db
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Sunday, June 22, 2003 12:55 PM
>Subject: Converting diodes to resistors
>
>
> > Original poster: "S & J Young by way of Terry Fritz <teslalist-at-qwest-dot-net>"
><youngs-at-konnections-dot-net>
> >
> > Semiconductor failure experts,
> >
> > I fried (over easy) a string of  15 1N5408s in my DC resonant charger
>power
> > supply.  Usually I have the spark gap across the supply & resonant choke
>and
> > the cap in series with the primary.  But I noticed in Richie Burnett's
>site
> > he showed the cap across the charging power supply and the gap in series
> > with the primary.  So I tried it.  BIG MISTAKE!  The RF caused a smoky and
> > stinky voltage breakdown in one of the MOTs I used for the charging
> > inductor.  The RF also wiped out a diode string.
> >
> > Question:  The diodes all still have the usual forward characteristics,
>but
> > the reverse resistance on all of them has gone from higher than 200
>megohms
> > when they are good, to around 12K.  They vary from 5 K to 20 K.  So, just
> > curious, what did the RF do to the diode junctions to make them act like
> > resistors?
> >
> > --Steve Y.
> >