8 Jan
2002
8 Jan
'02
4:18 a.m.
Another question from me :)
The Compukit UK101 has several ceramic capacitors, all marked 104Z 25V,
which judging by what I've found on the web so far makes them .1uF. My local
Maplins (sorry, that seems to be a swear word in some parts) only has 224Z
at 25V (I'd guess .2uF?) and 104Z at 50V, half the size.
What can I get away with? Or am I right in assuming I need to match exactly?
Ta for any help....
--
Adrian Graham, Corporate Microsystems Ltd
e: adrian.graham(a)corporatemicrosystems.com
w: www.corporatemicrosystems.com
w2: www.binarydinosaurs.co.uk (Online Computer Museum)
8 Jan
8 Jan
4:37 a.m.
Hi,
The Compukit UK101 has several ceramic capacitors, all
marked 104Z 25V,
which judging by what I've found on the web so far makes them .1uF. My local
Maplins (sorry, that seems to be a swear word in some parts) only has 224Z
at 25V (I'd guess .2uF?) and 104Z at 50V, half the size.
What can I get away with? Or am I right in assuming I need to match exactly?
It's ok - I know how it is with maplin - can be hard to pick up bits and
bobs these days, all the little stores are closing.
I don't remember my capacitor markings that well, but you seem to have
covered that. The voltage stated is a maximum working voltage, so you
should use the 104Z 50V version, *not* the 224Z.
Hope this helps :&)
-- Matt
---
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4:44 a.m.
On Tue, Jan 08, 2002 at 03:18:03PM -0000, Adrian Graham wrote:
The Compukit UK101 has several ceramic capacitors, all
marked 104Z 25V,
which judging by what I've found on the web so far makes them .1uF. My local
Maplins (sorry, that seems to be a swear word in some parts) only has 224Z
at 25V (I'd guess .2uF?) and 104Z at 50V, half the size.
What can I get away with? Or am I right in assuming I need to match exactly?
I am not up to date on capacitor markings, but I will say that it is
the capacitance that is important--that and the type of capacitor
(which implies inductance, leakage, and I am not sure whatelse).
The voltage is something you merely need to meet, exceeding it is OK.
Assuming everything else matches, I'd go with the "104Z at 50V".
-kb
5:21 a.m.
On Tue, 8 Jan 2002, Kent Borg wrote:
The voltage is something you merely need to meet,
exceeding it is OK.
Assuming everything else matches, I'd go with the "104Z at 50V".
-kb
Quick lesson in capacitor markings:
The number '104' indicates the capacitance, with the first two digits
'10'
being the 'mantissa' or value and the last digit being the exponent.
Ceramic (and other caps marked like this) are all rated in pF or 10^-9 F.
Therefore, this cap is 10x10^4pF or 100,000pF, or 0.10uF. The other
capacitor, 224Z, would be 0.22uF (22x10^4pF). The 'Z' specifies a
temperature range (IIRC) or something else that is not terribly important
for most applications.
-- Pat
5:55 a.m.
On Tue, 8 Jan 2002, Pat Finnegan wrote:
On Tue, 8 Jan 2002, Kent Borg wrote:
A few minor additions
pf = 10^-12 F (10 ^-9 uF)
Z probably stands for Z5U - the particular dielectric used. Z5U is a very
temperature unstable material but with a high dielectric constant, often
used for bypasses. Its so unstable that if you make an audio oscillator
with a Z5U capacitor determining the frequency, you can hear the pitch
change by just warming the capacitor with your finger...
X7R is a newer, somewhat more temperature stable material used for
bypasses.
Peter Wallace
The voltage is something you merely need to meet,
exceeding it is OK.
Assuming everything else matches, I'd go with the "104Z at 50V".
-kb
Quick lesson in capacitor markings:
The number '104' indicates the capacitance, with the first two digits
'10'
being the 'mantissa' or value and the last digit being the exponent.
Ceramic (and other caps marked like this) are all rated in pF or 10^-9 F.
Therefore, this cap is 10x10^4pF or 100,000pF, or 0.10uF. The other
capacitor, 224Z, would be 0.22uF (22x10^4pF). The 'Z' specifies a
temperature range (IIRC) or something else that is not terribly important
for most applications.
-- Pat
6:31 a.m.
On Tue, 8 Jan 2002, Peter C. Wallace wrote:
On Tue, 8 Jan 2002, Pat Finnegan wrote:
Oops should be (10 ^-6 uF)
Peter Wallace
On Tue, 8 Jan 2002, Kent Borg wrote:
A few minor additions
pf = 10^-12 F (10 ^-9 uF) The voltage is something you merely need to meet,
exceeding it is OK.
Assuming everything else matches, I'd go with the "104Z at 50V".
-kb
Quick lesson in capacitor markings:
The number '104' indicates the capacitance, with the first two digits
'10'
being the 'mantissa' or value and the last digit being the exponent.
Ceramic (and other caps marked like this) are all rated in pF or 10^-9 F.
Therefore, this cap is 10x10^4pF or 100,000pF, or 0.10uF. The other
capacitor, 224Z, would be 0.22uF (22x10^4pF). The 'Z' specifies a
temperature range (IIRC) or something else that is not terribly important
for most applications.
-- Pat
8:26 a.m.
New subject: {Ceramic} capacitor Q & A's
Quick lesson in capacitor markings:...
Thanks for this. I bought one of those 1000
capacitors / $3.00 bags a few years ago and
never quite knew what I had.
And thanks for the corrections.
If I may, here's a question.
I have a ton of ?electrolytic? 'cans' so how do I chose
the best cap for "Battery" style usage? (obviously not
for constant voltage, its a cap) Some must be best at
EG 60hz operation, and some for the longer charge
cycles - just which ones?
And does "forming" always help?
John A.
8:40 a.m.
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7:06 a.m.
From: ard(a)p850ug1.demon.co.uk (Tony Duell)
Subject: Re: Ceramic capacitor question
To: classiccmp(a)classiccmp.org
Date: Tue, 8 Jan 2002 19:40:48 +0000 (GMT)
Reply-to: classiccmp(a)classiccmp.org
> The Compukit UK101 has several ceramic
capacitors, all marked 104Z 25V,
Why do you suspect they're faulty (or why do you want to replace them).
Most of the time, ceramic capacitors are used for supply decoupling in
these machines, which is not a particularly critical application. And
ceramic caps tend to last quite a long time anyway.
Yes, they can fail, but unless you have a supply line short or something,
I'd not suspect them.
Feel free to suspect or not but I fixed a mysterious problem on a
custom machine. Alldata used to sell whole machines for data pull up
on vehicle info/parts/TSBs) machine based around peecee board (to be
on topic I also repaired much eariler alldata machine around a atari
ST1040,. 1MB, 68000 I think). Both use CD as medium for data pull
up.
Back to this peecee board, this one made rapid "reboots" or resets
or like voltages going on/off every second. PSU design is kinda
pulled off the shelf w/ HUGE external passive heatsink, noticed it
has no PG signal except a small board wart bolted to PSU external
casing. That little board has one 8pin IC. That IC is readily
available and at power up, outputs comes up after certain time set
internally by that IC and small components countable with one hand.
Nothing else. Cause: small yellow coated ceramic capacitor looks
good till unsoldered it off that little board, one leg fell off
leaving a hole in the dipped package. BINGO!
Cannot put in regular peecee PSU, this case is designed to be
fanless and ventless to prevent dirt, shop's dirty stuff getting in.
Requires 24V for thermal printer (like a fax printer) so repair
that PSU is necessary.
Cheers,
Wizard
1:33 p.m.
The 50V 104Z will work just as fine as the 25V type
It simply wont blow as easely in case of an overvoltage
event, but I'm sure some other devices on your board will!
Sipke de Wal
-----------------------------------------------
http://xgitor.ath.cx
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----- Original Message -----
From: Adrian Graham <Adrian.Graham(a)corporatemicrosystems.com>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, January 08, 2002 4:18 PM
Subject: Ceramic capacitor question
Another question from me :)
The Compukit UK101 has several ceramic capacitors, all marked 104Z 25V,
which judging by what I've found on the web so far makes them .1uF. My local
Maplins (sorry, that seems to be a swear word in some parts) only has 224Z
at 25V (I'd guess .2uF?) and 104Z at 50V, half the size.
What can I get away with? Or am I right in assuming I need to match exactly?
Ta for any help....
--
Adrian Graham, Corporate Microsystems Ltd
e: adrian.graham(a)corporatemicrosystems.com
w: www.corporatemicrosystems.com
w2: www.binarydinosaurs.co.uk (Online Computer Museum)
8227
days inactive
8227
days old
9 comments
9 participants
participants (9)
-
Adrian.Graham＠corporatemicrosystems.com -
allain＠panix.com -
ard＠p850ug1.demon.co.uk -
classiccmp＠knm.yi.org -
jpero＠sympatico.ca -
kentborg＠borg.org -
pat＠purdueriots.com -
pcw＠mesanet.com -
sipke＠wxs.nl