What is the physics behind it?

[gikiian]

What's the physics behind it?

 

[256bits]

Color coded so you know which is which.

 

[gsal]

Consistency, polarity convention.

This way, you can compare to voltages and know whether they are both the same polarity or not, e.g., they are 100V and 150V, or 100V and -150V.

 

[Gordianus]

I think it's the other way round. We usually connect the red cable to the positive terminal and the black to the negative.

 

[davenn]

I think it's the other way round. We usually connect the red cable to the positive terminal and the black to the negative.

You beat me to it :) yes exactly. I am a bit suprised the first 2 responders didnt pick up on that one lol

Dave

 

[Redbelly98]

I think it's the other way round. We usually connect the red cable to the positive terminal and the black to the negative.

I agree. And the only reason I can think of is that you would prefer to have a positive number for the meter reading. But it really isn't necessary; if you reverse the leads you just get -1 times the reading you would have gotten.