On Aug 21, 2006, at 8:41 PM, John Griessen wrote:
Do you hack code on the old machines and also hack on their circuit
boards/ Just how much hacking are we talking about here? grin
Both. Lots of both! 8-) I'm currently restoring a PDP-8/e with two
RK05 disk drives, a TU56 tape subsystem,
0.1 uF or 1 uF ? Same footprint (0603), the 1uFs are a few cents more
each (er, ~ 40% more cost for 10x the capacitance).
Don't know if the 0.1uFs have some benefits inductance-wise or
ESR-wise, in general.
This question (and those like it) is the topic of constant debate on
SI-LIST. My
I'm working on a simple sram/ethernet add-on card for one of my m32c
starter kits. It's a 2 layer 3.5x4.5 board, 32MHz signalling, and the
power and ground are tree structure - i.e. no planes (won't fit) -
with 20 mil traces (signals are 8 mil). Heck power and ground enter
the board about 3
Great minds think alike; I'm currently doing that. Caps are cheap, so
for the srams example, I'm using 0.1uF at each power pin (16 total),
and 1uF at the end of each sram bus (eight total). Plus scattering
some 10uF (also 0603 ceramic) around.
Hmmm, do you actually have 10uF 0603 ceramic caps
Hmmm, do you actually have 10uF 0603 ceramic caps in hand? I'd bet
dollars to doughnuts that you either haven't looked for them, or your
haven't ordered them yet (so you haven't found out that they are only
brochureware).
Digikey ECJ-1VB0J106M
It's the biggest value 0603 cap Panasonic
DJ -
On Mon, Aug 21, 2006 at 02:01:51PM -0400, DJ Delorie wrote:
Plus scattering some 10uF (also 0603 ceramic) around.
Or this one: digikey PCC2233CT-ND
10uF 0805 ceramic, 10v, +20% -80%, only $0.20 each.
Have you ever looked at the capacitance-vs-voltage
curves for Y5V dielectric? Yuck.
Have you ever looked at the capacitance-vs-voltage curves for Y5V
dielectric? Yuck.
I've been avoiding the 20/80 caps for anything other than bulk
bypassing, but I'm easily talked out of them completely.
OTOH this board will only see room temperature. I'll look for
high-temp-range parts for
Yeah, my sort algorithm (stolen from the web somewhere) sorts by
ASCII character, not by anything more intelligent. I can fix that
at some point.
pcb has a sort-helper that does the right thing, if you want to grab a
copy of it.
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geda-user
What about Al electrolytics? Like, for power supply bulk filtering?
The furnace controller will be seeing 34 Vdc peak, does that mean 100v
caps?
Yes, that's what I'd do.
Also, with electrolytics, you need to pay attention to the temp
rating. 85C rated caps are for cheap consumer junk. You
What about Al electrolytics? Like, for power supply bulk filtering?
The furnace controller will be seeing 34 Vdc peak, does that mean 100v
caps?
Yes, that's what I'd do.
I just located my copy of NASA practice no PD-ED-1201, which covers
electronic part derating. Table I in that doc calls
Also, with electrolytics, you need to pay attention to the temp
rating. 85C rated caps are for cheap consumer junk. You want at
least 105C for industrial equpt, IMO, and 125C is better
It's going to be bolted to my FURNACE. So yeah, high temp range is
good. It's on the duct that carries
On Aug 20, 2006, at 10:56 PM, DJ Delorie wrote:
0.1 uF or 1 uF ? Same footprint (0603), the 1uFs are a few cents more
each (er, ~ 40% more cost for 10x the capacitance).
Don't know if the 0.1uFs have some benefits inductance-wise or
ESR-wise, in general.
If they are both 0603, inductance
On 8/21/06, DJ Delorie [EMAIL PROTECTED] wrote:
Also, a Google search will turn up lots of info about how to
properly select an electrolytic cap.
Too much info. What keywords should I be using?
You may want to try the capacitor manufacturer websites --- Kemet,
AVX, Nichicon, etc.
(* jcl
You may want to try the capacitor manufacturer websites --- Kemet,
AVX, Nichicon, etc.
Ah, so Google isn't always my friend? ;-)
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Here are some links I found from electrolytic capacitor lifetime:
http://www.aavidthermalloy.com/technical/papers/capacitor.shtml
http://www.nichicon-us.com/english/seihin/pdfs/e-nx.pdf
http://powerelectronics.com/mag/power_optimize_electrolytic_capacitor/index.html
On Aug 21, 2006, at 1:26 PM, Stuart Brorson wrote:
Also remember that NASA recommendations tend to be super
conservative.
I would normally agree, except that NASA's 60% rating suggests using a
10V cap to hold off 6V, which seems too low to me. A 2X derating
would suggest at least 12V to
I updated the board online, adding five 10uF 0805s around the board.
One near each incoming power, two in the middle, and one at the other
end of the board. Plus the one 10uF on the 3.3v regulator.
I feel like I'm beating this horse far beyond the point where it's
already dead. . . . . .
But
0.1 uF or 1 uF ? Same footprint (0603), the 1uFs are a few cents more
each (er, ~ 40% more cost for 10x the capacitance).
Don't know if the 0.1uFs have some benefits inductance-wise or
ESR-wise, in general.
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