Cap values

L

Les Cargill

Guest
So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm

--
Les Cargill
 
"Les Cargill" <lcargill99@comcast.com> wrote in message
news:jevhfm$ijh$3@dont-email.me...
So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm

--
Les Cargill
Click to expand...
Its easy to find cap value tables online:

http://www.csgnetwork.com/capcodeinfo.html

0.1uF is 100 nF
0.01uF is 10nF or 10,000pF
0.001uF is 1nF or 1000pF
-and so on-
 
On Sun, 15 Jan 2012 15:51:10 -0600, Les Cargill <lcargill99@comcast.com>
wrote:

So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm
Click to expand...
It's in uF. Units of pF or nF wouldn't make sense and if it was in mF
then (I assume) they'd just annotate it as "1.0". Could be unadorned
farads but that's unusual enough that one would expect it to be so
indicated.

A quick Spice run (too lazy to breadboard it ;-) indicates that .001 uF
would behave in a sane manner...

--
Rich Webb Norfolk, VA
 
Ian Field wrote:
"Les Cargill"<lcargill99@comcast.com> wrote in message
news:jevhfm$ijh$3@dont-email.me...
So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm

--
Les Cargill

Its easy to find cap value tables online:

http://www.csgnetwork.com/capcodeinfo.html

0.1uF is 100 nF
0.01uF is 10nF or 10,000pF
0.001uF is 1nF or 1000pF
-and so on-
Click to expand...
The problem is that there are units on some of the caps,
no units on others. My question relates to what the default
units for a cap on a schematic generally are if there are
no units specified.

I can most likely manage conversions :) Slide dat decimal place...

--
Les Cargill
 
Rich Webb wrote:
On Sun, 15 Jan 2012 15:51:10 -0600, Les Cargill<lcargill99@comcast.com
wrote:

So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm

It's in uF. Units of pF or nF wouldn't make sense and if it was in mF
then (I assume) they'd just annotate it as "1.0". Could be unadorned
farads but that's unusual enough that one would expect it to be so
indicated.

A quick Spice run (too lazy to breadboard it ;-)
Click to expand...
I sincerely hope so! Even a Spice run would be way too much work...

indicates that .001 uF
would behave in a sane manner...
Click to expand...
Thank you.

--
Les Cargill
 
On Sun, 15 Jan 2012 15:51:10 -0600, Les Cargill wrote:

So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?
Click to expand...
The ARRL Handbook's old nomenclature was that fractional values like your
0.001 would be in microfarad, and decimal values (i.e. 33 or 100) would
be pF.

I would expect something similar. Particularly if the schematic is over
10 or 20 years old, anything 1uF and above is almost certainly going to
be electrolytic, and will be marked with polarity.

_My_ nomenclature, heavily influenced by my college physics courses, is
to put the correct dimensions on everything -- so that cap would be
labeled "1nF" or (under duress) 0.001uF.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
 
"Les Cargill" <lcargill99@comcast.com> wrote in message
news:jf2bdu$i57$1@dont-email.me...
Ian Field wrote:
"Les Cargill"<lcargill99@comcast.com> wrote in message
news:jevhfm$ijh$3@dont-email.me...
So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm

--
Les Cargill

Its easy to find cap value tables online:

http://www.csgnetwork.com/capcodeinfo.html

0.1uF is 100 nF
0.01uF is 10nF or 10,000pF
0.001uF is 1nF or 1000pF
-and so on-



The problem is that there are units on some of the caps,
no units on others. My question relates to what the default
units for a cap on a schematic generally are if there are
no units specified.

I can most likely manage conversions :) Slide dat decimal place...

--
Les Cargill
Click to expand...
The markings on capacitors are often ambiguous - you get used to it.
 
"Tim Wescott" wrote in message
news:juydneREzflSj4jSnZ2dnUVZ_sWdnZ2d@web-ster.com...

The ARRL Handbook's old nomenclature was that fractional values
like your 0.001 would be in microfarad, and decimal values (i.e. 33
or 100) would be pF.

I would expect something similar. Particularly if the schematic
is over 10 or 20 years old, anything 1uF and above is almost
certainly going to be electrolytic, and will be marked with polarity.

_My_ nomenclature, heavily influenced by my college physics
courses, is to put the correct dimensions on everything -- so
that cap would be labeled "1nF" or (under duress) 0.001uF.
Click to expand...
Many small capacitors (MLCs) use a three digit system based on pF, so 102 is
1000 pF. It can be confusing for a 10 pF capacitor which would be labeled
100, while a 100 pF would be 101. It's even more confusing, perhaps, for
values smaller than 10 pF, but they are relatively rare. And there are some
capacitors which use just one or two digits for actual values in pF.

There is also the nomenclature that uses the prefix for the decimal point,
which is helpful on some copies of schematics where the decimal point may be
very faint or disappear (as may happen in scanned copies and JPGs and the
like). I use a variation of that for my part numbering system, as in:

C_3N30_50V_5%_0805 which is 3.30 nF 50V 5% in a 0805 SMD package
C_25F0_2V7_D500_LS300 which is 25.0 Farads, 2.7V, in a 500mil diameter can
with 300mil lead spacing

I use a similar system for resistors, inductors, and other common
components. For ICs, transistors, and special components I use the part
number:

U_74HC139_SO16
Q_2N3904_TO92

I use these part numbers primarily for PCB design, so they are in the PADS
libraries. Someday I may also cross-reference them to a database where I can
keep track of cost, vendors, and quantities on hand.

Paul
 
On Mon, 16 Jan 2012 17:26:17 -0600, Les Cargill <lcargill99@comcast.com>
wrote:

Ian Field wrote:
"Les Cargill"<lcargill99@comcast.com> wrote in message
news:jevhfm$ijh$3@dont-email.me...
So I see an online schematic with a cap of value ".001" What are the
default units? Microfarads ( uf )?

Here's the schem ( C1 is designated .001 )
http://www.muzique.com/schem/mosfet.htm

--
Les Cargill

Its easy to find cap value tables online:

http://www.csgnetwork.com/capcodeinfo.html

0.1uF is 100 nF
0.01uF is 10nF or 10,000pF
0.001uF is 1nF or 1000pF
-and so on-



The problem is that there are units on some of the caps,
no units on others. My question relates to what the default
units for a cap on a schematic generally are if there are
no units specified.
Click to expand...
As others have said, the default units are almost always microfarads. If it's
something else it will be noted somewhere on the schematic.

>I can most likely manage conversions :) Slide dat decimal place...
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top