Voltage Rise and Voltage Drop

Author: E.E. Kimberly

When a voltage is generated in any device or in any part of a circuit, the point of positive potential is said to be at a higher potential than the point of negative potential. The means by which the voltage is generated is said to produce a voltage rise, and the rise is designated by the letter E. In some instances the instantaneous value of a changing voltage rise may be under consideration and it will be designated by e. When the circuit is completed, as in Fig. 3-1, the available voltage E forces a current through the remainder of the circuit and there is said to be a voltage drop through that part of the circuit. Drop in voltage is designated by the letter V.

Fig. 3-1. Circuit in example 3-1

The sum of all voltage rises in the circuit to the sum of all voltage drops. It may seem that, as indicated in Fig. 3-1, there is a distinction without a difference because E and V appear across the same points in the circuit. However, in more complicated circuits the distinction will be found to be valuable.