Re: Space Duel Power Supply -- Part II

The high PIV isn't needed. If the output of the 15 volt regulator
goes much over 15 volts you will have more to worry about than
replacing a diode! Anything rated at least 25 volts will be fine.

"Christopher X. Candreva" wrote:

> On Fri, 15 Oct 1999, Rodger Boots wrote:
>
> > Then it must be there to keep the output from getting driven
> > negative, probably during power-down of the game.
>
> That makes sense. Here's a bad ASCII diagram:
> |\
> Vin| \__________ +15
> ----| / | |
> |/| -+ -
> | -.1uf ^ 1N100
> | | |
> _____|__________
> Gnd
>
> > > > voltage. You can use any diode with a HIGHER PIV, but not lower... if the
> > > > orig was 100 PIV, go down to RAT shack and get a diode with 100+ PIV --
> > > > many go 200, 300, etc. The diode there is non critical in almost every
> > > > spec except PIV :)
>
> > The diode has to turn on before the innards of the regulator do.
> > Germanium turns on at about .2 volts instead of the .65 of silicon.
> > Schottky is somewhere in between, and you will have a hard time
> > finding a 100 volt Schottky. But as long as it's good for at least
> > 20 or 25 volts it should be fine.
>
> Difference of opinion. :-) But this is actually what I was originally
> thinking. RS has the 1N34A, which is germaniuam, but only has a PIV of 60v.
> Unless this supply is powering the counter or something, I can't imagine
> it's going to have such large voltages to deal with.
>
> Of course the real solution is to get the right part. Makes me REALLY wish I
> had a decent place to buy from locally. Speading $4 shipping on a $.50 part
> drives me nuts.
>
> I'm going to trace through this some more to see what this +15 drives, other
> than the vector generator sections. Anyone who knows why such a high PIV is
> needed feel free to smack me upside the head.
> :-)
>
> -Chris
>
> ==========================================================
> Chris Candreva -- chris@westnet.com -- (914) 967-7816
> WestNet Internet Services of Westchester
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Received on Fri Oct 15 13:48:37 1999