Re: (Hopefully) simple Battle Zone problem

On Thu, 15 Oct 1998, Christopher X. Candreva wrote:

>
> OK -- I'm still a bit confused here, so . . .
>

<snip>

>
> OK, so remembering my basic power supply knowledge, it's the PRV of the
> diode that determines the output voltage.

        That's wrong. I'm not exactly sure what you mean by "output
voltage," but when a diode is on, it is the Vf that is most important.
When the diode is on, there will be Vf across the diode. When the diode
is reverse-biased, it will usually just be off, but if the "reverse"
voltage is large enough, it will cause the junction of the diode to go
into an "avalanche breakdown" mode, where the diode is usually permamantly
damaged. This voltage where the diode goes into this mode is
essentially the PRV.

> Does this mean that the 19V2000 needs a DIFFERENT diode, to make the 14.5kv
> instead of 12kV ? As in, SK7333 is actually wrong, since it crosses to H1812
> instead of H1809 ?

        No. You can use a diode with a higher PRV (i.e. the SK7333) no
problem, but you can't use a diode with a 12kV PRV in the 19V2000. As is
the case with most NTE/ECG/SK parts, the NTE527A, etc is over-speced, and
actually has a PRV of 35kV, well above what is necessary.

> Mouser lists some general, high-voltage rectifiers. In the .35 amp range, we
> have
>
> PRV IFM (Surge A)
> HVM14 14000 50
> HVM16 16000 50

        THe HVM16 looks like it will work for both applications.
The HVM14 will work for the G05, but not the 19V2000, as they are speced
in the monitor manuals.
 
> Would one of those do ? If I understand what you are saying the PRV value
> has to be within +- 300V of 14.5kV ?

        No, the Vf value should be as small as possible, but definitely
not larger than 300V. THe PRV should be at least as big as the HV of the
monitor.

Joe
Received on Thu Oct 15 00:06:49 1998