Re: Can't find info about addon card for HP-150 #VintageHPComputers


On 5/31/21 5:47 PM, Sonno Ocea wrote:
The danger of replacing electrolytic capacitors with MLCCs is that the
latter tend to have issues with voltage coefficient of capacitance, i.e.
the capacitance goes down as the voltage across the capacitor increases.

I knew there were differences but I never had someone explain to me, too
practical for formal lessons, too advanced for random tutorials on the
internet. xD
Yeah. College professors naively think all components are "perfect",
and the eyes of random forum kids glaze over when people talk about tech
in-depth...if they can blink an LED with an Arduino in less than a week
of work, suddenly they're electronics experts. Sigh.

When doing design, the capacitance of a capacitor is only one of about
eight parameters that one must consider.

I've seen some on lcsc and digikey: I wanted to use polymer ones so they
don't leak corrosive stuff.
Yes, I've designed with aluminum organic polymer capacitors, they're
very nice. No liquid electrolyte to boil, so no "K" stamps on the top.
Another good option is niobium pentoxide. Tantalum capacitors are
excellent, but only if properly applied.

Sadly they seem to cost 10x more or they last 10x less than similarly
priced Nichicon ones so I'm not really sure on what to use.
Well, you're only buying one (or a couple)..

Also I did some reserch on my own and found out the AMD 8088-2
dissipates about 2W, so I think I'll stick a tiny heatsink on it.
I would. It certainly won't hurt.

Thanks a lot for the response!
You're welcome.


Dave McGuire, AK4HZ
New Kensington, PA

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