On 4/4/22 08:54, Ken Kundert wrote: > Now consider the issue of “unitless units”. In electrical circuit we often talk > about gain, which it the ratio between the signal level at the output of > a circuit relative to the signal level at the input. But you need to be > specific about how you measure signal level. Typically, it would be a voltage, > current, or power level. Consider a circuit where both the input and output are > measured in volts. Then the gain would have units of "V/V", which is unitless > in dimensional analysis. But units of "V/V" (voltage gain) is much different > from units of "A/A" (current gain) or "W/W" (power gain), even though they have > the same dimensions. Mixing them up results in errors and confusion. An > additional complication is that sometimes logarithmic units are used. For > example, decibels in voltage, or dBV, is 20*log(Vout/Vin). Again, > a dimensionless quantity, but nonetheless "dBV" much different from "V/V".
[several other examples elided] It seems to me that these "unitless' units actually have units, even if they *appear* to cancel each other out. -- ~Ethan~ _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/XLRERZPX4WP7S4D4WZ7DB3XSKICQJLDX/ Code of Conduct: http://python.org/psf/codeofconduct/
