Re: Please clarify European resistor value notation for me



Joerg wrote:

Eeyore wrote:
Joerg wrote:
Eeyore wrote:
Joerg wrote:
Jim Thompson wrote:
Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote:

Just imagine a missing dot on a 2.2ohm inrush limiter and someone puts a
22ohm in there. Click - POOF.

The way I work a missing dot would get caught at LVS (layout versus
schematic), the netlists wouldn't match.

Well, yes, same here. But that doesn't help the poor guy who reads a
faded schematic and thinks, wow, I've got that 22ohms right here.


This is where the 'European' scheme wins hands down.

So how do they write 2.2 Ohms?


2R2.

In the 70s the idea was floated to use 'E' as in 2E2 - and I've seen it used a
few times but R ended up being adopted .


Ouch! E as in Eurocrat? That would collide with pretty much any SW and
scientific convention where they use that as exponent header. 5E6 would
then be interpreted as 5.6 by a few and 5M by most others.

The idea was indeed 'exponent' as in exponent zero AIUI. In any case it fell by the
wayside. An 'e' is apparenty 2.54 mm btw. Another one that never really took off. A
token attempt to include the inch in metric drawings.


When drawing circuits on a piece of paper I far prefer the old style ( US )
method of drawing a resistor though.

I don't 'get' the funny US caps with curly plates though.

On CAD I do. Can be very handy when you need to indicate where the
outside layer should be connected to. That can matter a lot in audio gear.

I make my own symbols for electrolytic caps a la European version.

What non-electrolytics tell you which is the outer layer btw ? Incidentally the can
isn't reliably the negative terminal in radial electrolytics - it tends to be
floating.

Graham

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Relevant Pages

  • Re: Please clarify European resistor value notation for me
    ... The idea was indeed 'exponent' as in exponent zero AIUI. ... token attempt to include the inch in metric drawings. ... I make my own symbols for electrolytic caps a la European version. ... What non-electrolytics tell you which is the outer layer btw? ...
    (sci.electronics.design)
  • Re: Please clarify European resistor value notation for me
    ... The idea was indeed 'exponent' as in exponent zero AIUI. ... An 'e' is apparenty 2.54 mm btw. ... I make my own symbols for electrolytic caps a la European version. ... On top of the line foil capacitors that is often indicated by a bar ...
    (sci.electronics.design)