100nF vs. 0.1uF

I like to use `104` ;-)

Best regards, Spehro Pefhany

I'm middle skool and switched from 0.1uF to 100nF. The decimal place doesn't get lost which is a problem with my eye sight getting worse (I don't like wearing glasses).

-- Mark

UK hobby magazines like Practical Wireless seemed only to recognise pF and uF in the sixties, and nF came along later with other publications like ETI and Elektor having external (Aus/Euro) influence.

Chris

When I went to skool, it was micro-microfarads or uuF.

I like to do everything in pF. Besides driving everyone nuts, it helps prevent my chronic and apparently incureable order of magnitude errors. I also like the sound of pF = "puff", which is usually what happens to my circuits.

Conversion tool:

Mark, How are you doing with all the fires around Santa Barbara?

...Jim Thompson

No decimal points.

I have preferred to used 100nf for many years, but don't find a problem with 0.1uf either.

One problem which does occur from time to time (especially with multi-generation photocopied circuit diagrams) is loss of the decimal point. This is where the continental system of using the unit as a decimal point really does have a big advantage. Thus "6.8pf" becomes "6p8f" and "2.2nf" becomes "2n2f".

I have always found the British Standard symbols for electrolytic capacitors are confusing (and difficult to draw), so I dug around to find out what alternatives were available. Eventually I settled for the pre-war German symbol, which I find completely unambiguous and self-explanatory:

I use that style of capacitor symbol for microwave capacitors that have a "preferred" geometry for mounting. (I.e., you can mount them backwards and they're still capacitors, but their frequency response is noticeably different [out past 1GHz] than when they're mounting the other way around.)

US clients 0.1uF, foreign clients 100nF. Unless I see something different on their schematics or they tell me their preference. Same with part symbols.

For really, really traditional clients it'll be 100 jars :-)

Reminds me of the classic "GE circuit" mike/tape/phono preamp, except that it only used two transistors.

But why the pair of 1 milliohm resistors?

John

Same reason as the use of a lower-case f for farads, which is usually represented by a capital F, and selective use of the omega symbol for ohms - a capital R is often used for 220 R, for example. I haven't looked but BS3939 probably gives a consistent set of rules.

Also, a former employee once asked me why I considered it so important always to insert a space between the number and the unit ... so I typed 21lb and asked her what it meant. Less ambiguous typed as 21 lb.

Chris

I think that nowadays, personal preferences are generally over-ridden by the exigencies of SW GUIs.

I note that you also don't seem to like crossed wires or connection dots. This would never fly. I'm a 'loop = no-connection ' guy, myself, but only when it's pen on paper.

RL

CAD programs generally couldn't care less which style you use, although companies that have a database of components presumably end up having a certain standard.

In the vein of, "schematic capture programs are actually rather poor in adopting conventions from other drawing/CAD programs," most schematic capture programs don't do the little "loop over an orthogonal wire = no connection" bit, even though much simpler programs like Visio do. Anyone know of schematic capture programs that does? Pulsonix doesn't, ORCAD C(r)apture doesn't, Altium didn't last time I used it...

---Joel

Wonder how one would symbolize that so that both ends of the "loop" would have the same net name?

Charlie Edmondson? Two pins with the same name ?:-)

...Jim Thompson

"Joel Koltner"

I reckon that should be your guide.

..... Phil

Well, the vast bulk of caps I use today are surface mount without markings.

Different manufacturers' datasheets use different nomenclatures.

---Joel

"Joel Koltner" "Phil Allison"

- you pedantic f*****ad.

...... Phil

I guarantee you that well over 90% of the tens of thousands of capacitors sitting within a few hundred feet of me here have no markings whatsoever on them.

Even if they were marked, the question was about how capacitors are shown on schematics -- how capacitors are physical marked may play into this, but it doesn't have to. (This gets into the classic debate over whether schematic symbols for connectors should be made to look like the physical part of not -- you can certainly make decent arguments on both sides.)