Potential Difference, Voltage

Potential Difference, Voltage Points : Potential Difference, Voltage In section the absolute potential of a point was defined as the amount of work done to bring a unit positive charge from infinity to that point. Most of the time we are not concerned with the absolute potential of a point but with potential difference between two points. Suppose we have three neutral bodies A, B and C. To body A we add electrons and the amount of the work done builds up a potential -10 volts. On body B we also add electrons but less work is done and its potential is -6volts. From body C we take away electrons and the work done builds up a potential of +12 volts. The potential difference between A and B is 4 volts, between B and C it is 8 volts and between A and C it is 22 volts. The potential difference is also called voltage and is measured in volts:
When talking about potential difference or voltage it is more appropriate to, designate it as voltage rise or voltage drop. From Point B and A there is a voltage drop of 4 volts and it is generally written as V_BA (i.e. voltage of point B with respect to A or voltage drop from point B to A). From point A to B there is a voltage rises of 4 volts. Therefore V_AB equals -4volts Evidently V_AB equal -V_BA.