# Electric potential in a cicuit

Look at the image at (http://sub.allaboutcircuits.com/images/00082.png). Ignoring all the resistors in the diagram and assuming that the charged particles flow as arrows show, why does the electric potential/voltage decrease from point 4 to 3 to 2 to 1? I thought that the electric potential/voltage will be higher at point 3 than point 4 as the distance between the positive end of the battery and point 3 is further than the distance between the positive end of the battery and point 4?

• allaboutcircuits doesn't seem to have adopted the same convention on current flow as the rest of the world.
– Chu
Feb 13 '16 at 10:11

simulate this circuit – Schematic created using CircuitLab

Figure 1. Circuit.

• Yes, electron flow is from the negative terminal. However, conventional current flow was established well before the discovery of the electron (by J.J.Thomson discovered in 1897) as from + to - and we still use this for practical applications while keeping the true charge flow in the back of our minds. Current flow is in the direction of the red arrow on Figure 1.
• We need to take some point as reference on our circuit. Battery negative is the usual choice.
• The point of maximum potential is node 1.
• The potential decreases from 1 to 2, from 2 to 3 and from 3 to 4 as per resistor ratio. For example, if R1 = R2 and R3 = R1 + R2 then the potential at node 3 = Vbat/2 and potential at node 2 = 3/4 Vbat.

So your understanding is correct apart from conventional current flow. Without a link to the article it's difficult to know what caused your confusion.

• Thanks for the help. However I apologize for not stating my question properly. I know that in static electricity the potential depends on the distance between 2 electric charges. In the circuit above, node 2 is further away in length from the negative end of the battery compared to node 3. So shouldnt the charge at node 2 have a higher potential? Thank you for helping Feb 14 '16 at 11:21
• Static electricity is quite different to an electrical circuit such as the one in your question. In static there is an imbalance in charge and an object can hold this because there are insulators. In the circuit there is no net charge at any point. i.e., at Node 2 there are no missing or extra electrons. There is a difference in potential between 2 and 3 and, yes, 2 is higher but there is no 'charge' there. Feb 14 '16 at 13:27