Re: diode check

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

Original poster: "colin.heath4 by way of Terry Fritz <twftesla-at-qwest-dot-net>" <colin.heath4-at-ntlworld-dot-com>

hi ]
the best way is to use an insulation resistance tester or megger as they are
known in the uk
these output 500 or 1000 volts so are just right for testing high voltage
diodes
cheers

colin----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, August 24, 2002 6:12 PM
Subject: Re: diode check


> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
>
> You'll need some sort of higher voltage supply to check the diode than the
> volt or so the VOM uses.  Something around 20-24 V should do.. Hook the 20
V
> in series with a 1 K resistor (or 470 or something..) that will limit the
> current to around 20 mA.  Now try the diode in both orientations.. A
simple
> VOM across the resistor will work..  zero volts means no current flow..
>
> In one orientation, you'll get some current flow.. typically, these MOT
> diodes have about 10 V forward voltage drop, so you'll see the difference
> across the resistor.  In the opposite direction, you'll see no current.
>
> Bear in mind that the MOT diode is actually a bunch of lower voltage
diodes
> in series inside the encapsulation, and it is entirely possible that
you've
> blown up just one of them.  There are three possible situations facing
you:
>
> 1) Totally fried and open.. no current either way
> 2) Totally fried and shorted.. current both ways
> 3) some diodes shorted.. current one way, but PIV and forward voltage drop
> reduced.
>
> if you have another (known good) diode of the same type to compare
against,
> it helps...
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, August 23, 2002 9:53 PM
> Subject: diode check
>
>
> > Original poster: "Steven Ward by way of Terry Fritz
<twftesla-at-qwest-dot-net>"
> <srward16-at-hotmail-dot-com>
> >
> >
> > Hi,
> >
> > I was caught up in the moment and snagged the diode from my VTTC to use
it
> > on a voltage multiplier.  Well the multiplier killed at least one of my
> > diodes(multiplier doesnt work), and i dont know which one.  I want to
put
> > the good one back on the tube coil but i dont know how to test the
diodes.
> > Does anyone know how?  I have a basic multimeter(VOM).  I think that
> someone
> > posted something awhile ago about this.  Oh, and its a microwave oven
> diode.
> >   Thanks
> >
> > Steve Ward
> >
> >
> >
>
>
>
>