----- Original Message ----- From: "Robert B." To: Sent: Thursday, April 15, 2004 3:26 PM Subject: Re: [EE]: Why isn't Ohm's Law written I=V/R? > ----- Original Message ----- > From: "Rick Regan" > > But aren't R and V the only two of the three variables > > that you can manipulate directly? > > No, not really. There is a current source in the EE lab that maintains a > set current regardless of voltage or resistance (within reason). I think > ordinary transistors do this to some extent also, as they are current > amplifying devices. It just so happens that most people are more acquainted > with measurements in voltage due to the use of batteries, wall warts, etc. > A current source makes I an independent variable. Also there are some > applications where R changes with I, which makes R the dependent variable! > > So in terms of which is the "proper" way to write it, I'd say it really > doesn't matter. It's probably just easiest to avoid the fraction, so most > people write E=IR. > > > > > I think writing it I=V/R would be less confusing > > to the novice. With the V=IR form, I've seen > > descriptions like "if the current doubles the voltage doubles." > Mathematically, yes, but it's not like you can > > double the current independently of V and R. > > > > -- > > http://www.piclist.com hint: To leave the PICList > > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu