Resistors 100R and 47R
- Thread starter Pasquada
- Start date
drew.spriggs
Well-known member
R just means resistance - makes it clear that 100 is 100, and not 100k.
dot matrix madness
Active member
Since the greek character for Ohm is not straight forward available on most keyboards/fonts "R" is used instead.
As @drew.spriggs pointed out, it makes absolutely sure which value is meant.
As @drew.spriggs pointed out, it makes absolutely sure which value is meant.
Feral Feline
Well-known member
Another reason for the "r" is that the Omega may be misconstrued as an extra zero, depending on the size and font choice of the text:
I prefer to use lower case "r" because at a glance an upper-case R may be misconstrued as a K —
The OHM symbol, Ω, is easily obtained on a Mac with "OPTION-ZED":
Press the OPTION key while using "Keyboard Viewer" and you can see what each key becomes...
Of course, you don't need to pull up the Keyboard Viewer to use OPTION-ZED, just press the two keys and you get a perfect Greek Omega every time.
Also, if you want to have the symbol for MICRO instead of wussing out with a letter "u", press OPTION-M and you get the proper "µ", so your micro-farads can be properly addressed, for example "10µF"
(Having caps-lock on screws up the OPTION-key combos, btw)
120Ω vs 1200
I prefer to use lower case "r" because at a glance an upper-case R may be misconstrued as a K —
100r 100k
100R 100k
100R 100K
100r 100K
The OHM symbol, Ω, is easily obtained on a Mac with "OPTION-ZED":
Press the OPTION key while using "Keyboard Viewer" and you can see what each key becomes...
Of course, you don't need to pull up the Keyboard Viewer to use OPTION-ZED, just press the two keys and you get a perfect Greek Omega every time.
Also, if you want to have the symbol for MICRO instead of wussing out with a letter "u", press OPTION-M and you get the proper "µ", so your micro-farads can be properly addressed, for example "10µF"
(Having caps-lock on screws up the OPTION-key combos, btw)
Erik S
Well-known member
It's been a long time since I messed with any special characters. I remember at some point having a post-it with a list of alt-codes for doing it in windows. Alt+230 on the number pad in Windows will also get you a "µ". Weirdly only works with the numbers on the number pad though.
Apparently Window key + period key will also get you to a special symbols menu I wasn't aware of.
Fama
Well-known member
Ohm and 0 gets especially tricky because sometimes the symbols can be partially cut off by the pads on PCB's. That's also why I agree, 100r would be better than 100R. Thankfully PPCB boards are always very clean about this and I don't remember seeing it happen, but it does happen on some other boards (arguably it's also a point for RefDes, although those have their own issues with some designations looking pretty identical due to some part of the symbols being cut off).
Feral Feline
Well-known member
EXACTICKLY-wickly — clarity — it's so easy to miss the decimal point with a poor resolution screen/print-out, smeared page etc...
.
Is that a smudge on your screen or did I sneak in a decimal, somewhere, full stop?
really appreciate your time explaining this.