cap help

Archiver

Hi all,

Can someone help me find out how to read caps. One has on it 22, another has 184, another has 563K, and another has 223K. They do not have a voltage value on them and they are non-polarized. These are only a snip of what I have.

Thanks

TC

Archiver

I was going to suggest looking in the "Art of Electronics" student manual,
which has a couple of pages on reading caps.

I did a search on google for "reading capacitor values" to see if there
was anything on the web. The top hit:
http://www.seas.upenn.edu/courses/belab/ReferenceFiles/capacitor_values.pdf
is a pdf of those pages...

there is another link further down that also explains it well:
http://members.nbci.com/talkingelect/1000_page5a.html


hope it helps,


Nick

On Thu, 21 Jun 2001, Anthony Conti wrote:

> Hi all,
>
> Can someone help me find out how to read caps. One has on it 22, another has
184, another has 563K, and another has 223K. They do not have a voltage value on
them and they are non-polarized. These are only a snip of what I have.
>
> Thanks
>
> TC
>

Archiver

Small, non-polarized caps such as these are generally marked in picofarads,
where the first two digits are the numeric value and the third digit is the
number of following zeros. Therefore:

22 = 22pF
184 = 180,000pf or 0.18uF
563 = 56,000pF or 0.056uF
223 = 22,000pF or 0.022uF

Bob Baxter

At 03:20 PM 6/21/01 -0400, you wrote:
> Hi all, Can someone help me find out how to read caps. One has on it
>22, another has 184, another has 563K, and another has 223K. They do not
>have a voltage value on them and they are non-polarized. These are only a
>snip of what I have. Thanks TC
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> Text in the Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

Archiver

At 03:20 PM 6/21/01 -0400, you wrote:
>Hi all,
>
>Can someone help me find out how to read caps. One has on it 22, another
>has 184, another has 563K, and another has 223K. They do not have a
>voltage value on them and they are non-polarized. These are only a snip of
>what I have.
>
>Thanks
>
>TC

Reading capacitors is just like reading resistors, only different. It is
not much more difficult, but unfortunately there are several common conventions
for marking capacitors. Some capacitors will have the value written on the
side (eg, 10mF (microFarad, 10-6 F), or 220mF). Some will have a number 0.01
or 0.003, in this case the unit is usually assumed to be mF. The third common
convention is much like that for resistors and consists of three number
followed by a letter. The letter is the tolerance, and the three numbers
denote the value and are read in the same way as that for resistors except the
base unit is pF (picoFarad, 1 pF = 10-12 F = 10-6 mF). So a marking of 154 is
= 15*10^4 pF
or
= 1.5*10^5 pF
or
= 150000 pF
or
= 0.15 mF.

A common mistake is to think of a pF as 10-3 mF instead of as 10-6 mF, but
this is a nF (nanoFarad, 10-9 F). However the term nF is seldom used, 1 nF
is either expressed as 0.001 mF, or as 1000 pF.



tolerance:
D = ± 0.5pF
F = ± 1%
G = ± 2%
H = ± 3%
J = ± 5%
K = ± 10%
M = ± 20%
P = +100%, -0%
Z = +80%, -20%

---

Beau Schwabe IC Mask Designer
National Semiconductor Wired Communications Division
500 Pinnacle Court, Suite 525 Mail Stop GA1 Norcross, GA 30071

---