In rec.radio.amateur.homebrew Michael Black wrote:
On Tue, 21 Aug 2018, wrote:

In rec.radio.amateur.homebrew Phi wrote:

wrote in message
...
In rec.radio.amateur.homebrew Phi wrote:

"Gareth's Downstairs Computer"
wrote in message
news You know, the ones in the clear plastic blobs, wire
ended with low puffage values and reputed to be super
stable?

Silver mica were the best.

Got any 1,000 uF silver micas?

--
Jim Pennino


Perhaps you forgot or don't know, they are not electrolytic.

Neither silver mica nor polystyrene capacitors are electrolytic.

What's your point?

Perhaps you forgot or don't know that in general polystyrene capacitors
are advantageous at audio frequencies while silver micas are advantageous
at RF frequencies and fill two entirely needs.

Read this:

https://en.wikipedia.org/wiki/Film_c...ilm_capacitors

Except "1,000uF" is a large value of capacitance, more in line for audio
than RF.

No ****?

Perhaps that is why I made the comment about polystyrene capacitors
being more advantageous at audio frequencies.

At that value, virtually everyone shifts to an electrolytic
capacitor since it's the only way to get the value cheap and in a
reasonably sized package.

That depends on the application.

I admit to misreading it when I read it first, me thinking "1,000 pF"
which of course is .001uF and a value not common for the sort of thing
being discussed.

What thing is that?

The post that started this is "Silver mica were the best." without mentioning
best at what.

It's a common RF bypass value, where you wouldn't need
an exact value and hence no need for polystyrene capacitors.

And since no one except your imagination said anything about "1,000 pF",
so what?

Yes, I know
there are exceptions, but generally it is a high value for RF frequency
control purposes.

Who said anything about RF frequency control purposes?

As for what happened to them, they came "late", and then I thought they
had just sort of morphed, either under a different name or something else
came along that was equivalent, but I admit I've not paid attention.

If you had bothered to read my link above, you would know what happened
to them and would not be making wild ass guesses.


--
Jim Pennino

On 22/08/2018 09:50, Jeff wrote:
Suflex capacitors. Scourge of the devil. I always viewed them with
suspicion when fault finding.


Suflex were a particular make, rather than a type.

There was another brand, Styroflex perhaps, which I think were similar.

I'm sure there were others, those just spring to mind.


I don't why everyone is talking in the past tense they are still readily
available, not Suflex but other brands, from RS, Farnell etc.

Jeff

These days, at least when buying for home use, I tend not to look at the
make.

In the days when I was involved in circuit design professionally,
picking specific parts was common - not only performance but 'second
source' availability, expected long term availability, ...... etc.

These days, it tends to be basic technical requirements. Not brands.
With Ebay etc, even cost tends to be a minor issue.



--

Remarkable Coincidences:
The Stock Market Crashes of 1929 and 2008 happened on the same
date in October. In Oct 1907, a run on the Knickerbocker Trust
Company led to the Great Depression.

On 21/08/18 19:08, wrote:
In rec.radio.amateur.homebrew Phi wrote:

"Gareth's Downstairs Computer"
wrote in message
news
You know, the ones in the clear plastic blobs, wire
ended with low puffage values and reputed to be super
stable?

Silver mica were the best.

Got any 1,000 uF silver micas?

=====================
Polystyrene and silver mica caps are still available to my knowledge
(JAB Electronics -UK)

Frank , EI7KS

In rec.radio.amateur.homebrew wicklowham wrote:
On 21/08/18 19:08, wrote:
In rec.radio.amateur.homebrew Phi wrote:

"Gareth's Downstairs Computer"
wrote in message
news You know, the ones in the clear plastic blobs, wire
ended with low puffage values and reputed to be super
stable?

Silver mica were the best.

Got any 1,000 uF silver micas?

=====================
Polystyrene and silver mica caps are still available to my knowledge
(JAB Electronics -UK)

https://en.wikipedia.org/wiki/Film_c...ilm_capacitors

--
Jim Pennino