Capacitor general questions...
Robert Banks
Hello,
I've recently taken up building circuits as a hobby and have recently
acquired a bunch of small ceramic disc capacitors. My question is regarding
the markings on the capacitors. For example, ".02Z 100v". I assume the
'100v' is stating the maximum voltage. I would even wager a guess that .02
is some sort of Farad measure. But what is the Z? microFarads? Some
others include "RMC 470-10% N2200", ".33Z 3V", "MP 104Z 25V".
Thanks! I also heard that colors have something to do with the farad
measures? Thanks again!
nob...@nowhere.net
The .02 is .02uF. As for the Z I can't recall but it might be
tolerance. 470-10% sounds like an electrolytic at 470uF, 10%. The .33
is .33uF,3V and the 104 is read 10 + 4 0's as in 100000pF or when
divided by 1,000,000 yields .1uF at 25V.
Tom Bruhns
: I've recently taken up building circuits as a hobby and have recently
: acquired a bunch of small ceramic disc capacitors. My question is regarding
: the markings on the capacitors. For example, ".02Z 100v". I assume the
: '100v' is stating the maximum voltage. I would even wager a guess that .02
: is some sort of Farad measure. But what is the Z? microFarads? Some
: others include "RMC 470-10% N2200", ".33Z 3V", "MP 104Z 25V".
Seems like the Z should be "Z5U" temperature characteristic. That
specifies a tolerance over a temperature range. Ceramic caps are
usually divided into bypass types where large changes with temperature
aren't too important, and types that would be used in filter or
timing or tuning applications, where known temperature stability or
specific drift rate are important.
The "RMC" should be a manufacturer. The 470 can be deceptive: in some
cases it means 470pF, and in others it means 47, followed by 0 zeros,
or just 47pF...in this particular case, I'd guess it means 470pF.
The N2200 means it's a controlled-temperature-coefficient capacitor
that moves about 2200 parts per million, or 0.22 percent, per degree
Centigrade, in a N_egative direction. That is, increase temp causes
decreased capacitance. 104Z should be 10 plus 4 zeros = 100000pF = 0.1uF.
The problem stems largely from the fact that each manufacturer has his own
way to mark his capacitors, and even that changes over time for a
particular manufacturer.
: Thanks! I also heard that colors have something to do with the farad
: measures? Thanks again!
Colors? Yes, some caps are color coded. I think _usually_ the color codes
are digit-digit-number_of_zeros sorts of things, and the value is in pF.
--
Cheers,
Tom
to...@lsid.hp.com
a92...@zipi.fi.upm.es
In article <6e4tqd$2jb$1...@ha2.rdc1.pa.home.com>, "Robert Banks" <ba...@home.com> writes:
> Hello,
>
> I've recently taken up building circuits as a hobby and have recently
> acquired a bunch of small ceramic disc capacitors. My question is regarding
> the markings on the capacitors. For example, ".02Z 100v". I assume the
> '100v' is stating the maximum voltage. I would even wager a guess that .02
> is some sort of Farad measure. But what is the Z? microFarads? Some
> others include "RMC 470-10% N2200", ".33Z 3V", "MP 104Z 25V".
>
> measures? Thanks again!
>
When the reference is given starting with a dot, it's always in microfarads.
.022 -> .022uF
When you get 3 digits and a letter, the foormer 2 digits are the most
significant digits of the value, and the latter is the number of 0's (in pF)
103Z ->10000 pF->10 nF
The letter (usually Z or K) is the tolerance, but I don't know the meaning
of each one.
Eduardo Gimeno.
Segovia-Spain.
Paul Braunbehrens
I really appreciate all the help us novices got on this one, I even did a
DejaNews search and found more stuff, but I'm still stumped on a few caps.
For example, I have some that have a value, a line under that, and a period
under the line. Is this to be interpreted as if the period was a decimal
place and therefore the value is in uF? Also, is M sometimes used to
abbreviate uF, or is that always a tolerance. And finally, I have a lot of
stuff that has 3 digits, with the last one being a zero. What is the rule,
does 330 mean 33 picofarads, or does it mean 330 picofarads?
Urgh, I wish they would just print the stuff in a way that is readable, I
guess that'll teach my buying large bags of caps!
Thanks again for all the help, guys.
In article <6ehodc$6...@newsops.execpc.com>, en...@execpc.com (Robert Endl) wrote:
> The Z is probably the tolerance. Z is an EIA code for
> -20/+80%. Sounds like a low quality ceramic.
>
>
>
> On Tue, 10 Mar 1998 21:44:19 -0500, "Robert Banks" <ba...@home.com>
> wrote:
>
> >Hello,
> >
> > I've recently taken up building circuits as a hobby and have recently
> >acquired a bunch of small ceramic disc capacitors. My question is regarding
> >the markings on the capacitors. For example, ".02Z 100v". I assume the
> >'100v' is stating the maximum voltage. I would even wager a guess that .02
> >is some sort of Farad measure. But what is the Z? microFarads? Some
> >others include "RMC 470-10% N2200", ".33Z 3V", "MP 104Z 25V".
> >
> > Thanks! I also heard that colors have something to do with the farad
> >measures? Thanks again!
> >
>
> Send replies to: en...@execpc.com
--
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Robert Endl
Robert Endl
On Sun, 15 Mar 1998 17:28:24 -0800,
Bakali...@REMOVETHISBakalite.com (Paul Braunbehrens) wrote:
>I really appreciate all the help us novices got on this one, I even did a
>DejaNews search and found more stuff, but I'm still stumped on a few caps.
>For example, I have some that have a value, a line under that, and a period
>under the line. Is this to be interpreted as if the period was a decimal
>place and therefore the value is in uF? Also, is M sometimes used to
>abbreviate uF, or is that always a tolerance.
The M could be the tolerance, +-20%.
And finally, I have a lot of
>stuff that has 3 digits, with the last one being a zero. What is the rule,
>does 330 mean 33 picofarads, or does it mean 330 picofarads?
I have seen it both ways. You need a cheap capacitance meter.
>
>Urgh, I wish they would just print the stuff in a way that is readable, I
>guess that'll teach my buying large bags of caps!
We've all purchased a bag of caps, fun to play with but I
wouldn't build anything with them.
>
>Thanks again for all the help, guys.
>
>In article <6ehodc$6...@newsops.execpc.com>, en...@execpc.com (Robert Endl) wrote:
>
Send replies to: en...@execpc.com
Thomas Weeks
I have some Cap Q's regarding energy denisty and discharge rates..
If I were wanting to play around with homebrew railgun technology, are
polarized Electrolytic's the best storage medium to go with? I thought some of
the older railguns used racks and racks of such devices... but with the advent
of these extremely high density low voltage deives on the market, can anyone
here see the actual tradeoffs involved of one storage medium over another? I
would THINK that for higher power systems, you would want to concentrate on
increasing the CURRENT of the cpa->coil discharge--not the voltage...
am I off base here?
Email please: twe...@texas.net
Tom D Tek
Falk
Thomas Weeks wrote:
>
> I have some Cap Q's regarding energy denisty and discharge rates..
>
> If I were wanting to play around with homebrew railgun technology,
Wanna play around with railgun technology?? Simply try playing Quake II
;-)
> are
> polarized Electrolytic's the best storage medium to go with? I thought some of
NO,AFAIK their dicharge speed is not very high. (ok, still enough for
Xenon tubes)
> the older railguns used racks and racks of such devices... but with the advent
I dont know.
> of these extremely high density low voltage deives on the market, can anyone
I think you mean gold caps?? They are even slower than the electolytic
caps.
> here see the actual tradeoffs involved of one storage medium over another? I
> would THINK that for higher power systems, you would want to concentrate on
> increasing the CURRENT of the cpa->coil discharge--not the voltage...
The main goal is to increase the power density, that means as much as
possible energy in a very short time. Imagine a simple resistor in
series with a charged capacitor. The discharge can be decribes with the
function
I(time)=( Voltage of fully charged cap
)/resistance*exp(-time/(resistance*capacitance) )
The product of resistance and capacitance is the time constant (tc) of
the RC circuit. The capacitor is (practical) fully discharged after 5 *
tc. The energy stored in a cap can be calculated with
E = 0.5 * capacitance * (Voltage)^2
power is energy / time.
Here an example:
You have two circuts:
1st one: R=1 Ohm C=1 Farad V=1 Volt
-> tc=1s -> discharge time=5s
-> E = 0.5 Ws (Wattseconds = Joule)
-> power = E/time = 0.1 Watt
2nd one: R=1 Ohm C=0.25 Farad V=2 Volts
-> tc=0.25s -> discharge time=1.25 s
-> E = 0.5 Ws (same energy)
-> power = 0.4 W (4 times power)
You see??
--
CU Falk
Pamela Hughes
Falk wrote:
<snip>
> The main goal is to increase the power density, that means as much as
> possible energy in a very short time. Imagine a simple resistor in
> series with a charged capacitor. The discharge can be decribes with the
> function
>
> I(time)=( Voltage of fully charged cap
> )/resistance*exp(-time/(resistance*capacitance) )
>
> The product of resistance and capacitance is the time constant (tc) of
> the RC circuit. The capacitor is (practical) fully discharged after 5 *
> tc. The energy stored in a cap can be calculated with
>
> E = 0.5 * capacitance * (Voltage)^2
>
> power is energy / time.
>
> Here an example:
>
> You have two circuts:
>
> 1st one: R=1 Ohm C=1 Farad V=1 Volt
> -> tc=1s -> discharge time=5s
> -> E = 0.5 Ws (Wattseconds = Joule)
> -> power = E/time = 0.1 Watt
>
> 2nd one: R=1 Ohm C=0.25 Farad V=2 Volts
> -> tc=0.25s -> discharge time=1.25 s
> -> E = 0.5 Ws (same energy)
> -> power = 0.4 W (4 times power)
>
> You see??
>
> --
> CU Falk
Yes, your time constant will affect the output, therefore you want as much energy as
possible with a small delta T. Also, don't forget the effect of inductive
reactance... electrolytics are pretty bad at that too unless they were designed as
high speed discharge caps in the first place (some aren't and can't take a fast short
without destroying their internal connections). Would guess that it would be best to
use high voltage oil caps with very short and very thick leads. High voltage also
makes it possible to use a triggered arc for switching (there are special tubes that
do this, though they often contain a radioactive source, are banned from export since
they can be used in A-bomb triggers and are hard to obtain unless you stumble on a
source. As an alternative, you can just set two 1 inch brass spheres just far apart
enough that they don't arc, place a needle so the tip is near the space between them
and fire the thing by discharging a small cap through a flash trigger transformer
connected to the needle)