Circuit Diagrams

[Kari]

Hi. I'm a chemistry and biology student, and I just do electronics as a hobby on the side, so I don't know a whole lot.

I was wondering why circuit diagrams always depict current as flowing from the positive pole of the power source to its negative pole (e.g. diodes, transistors, etc.) Aren't electrons attracted to positive charge?

 

[(*steve*)]

Before there was conclusive proof, we had to have a convention. Positive to negative was chosen. Bzzzt.

This is actually pretty common. For example when map directions were being developed, North was considered to be the "top". Conclusive evidence now shows this to be wrong yet almost all maps are drawn upsidedown as a matter of convention.

I'm sure you can think of other cases.

 

[Merlin3189]

... when map directions were being developed, North was considered to be the "top". Conclusive evidence now shows this to be wrong ...

I'm intrigued! So what is top and why? Or do you just mean that, now we know the Earth is spheroidal and a sphere does not have a top? (Though if a billiard ball is on a table one might reasonably say the point in contact with the table is the bottom and the opposite point is the top.)
My own feeling is that there is no right or wrong in any of these things. Sometimes there are common conventions, but there's always someone who chooses to do it differently.

 

[(*steve*)]

I'm intrigued! So what is top and why?

Well, it should be obvious to you people standing on your heads in the northern hemisphere.

Yep, that was a joke. But it did get you thinking.

However, one could argue that if electrons had been known at the time, we still would have said that electricity flows from positive to negative. Electrons would then have a positive charge, we would have negatrons instead of positrons, and PNP transistors would perform better than NPN transistors.

If humans had evolved to be mostly left handed instead of right handed, would we still call the majority right handed, and would sinister still mean that someone that had the less common dominant hand?

If the magnetic poles had been the reverse of what they are now when magnetic north was named magnetic north, would all of our rules regarding magnetic fields, current and force be swapped over?

 

[shrtrnd]

Chemists vs Engineers, ....
This is why I became a tech.