2.2 Charge, Current, Voltage, and Power
For the most part, this text is concerned with
circuits in which only electron flow is relevant.
There are many devices (such as batteries, diodes,
and transistors) in which positive charge motion is
important to understanding internal operation.
However, external to such devices we typically
concentrate on the electrons which flow through
the connecting wires.
Note:
(1) Total number of positive and negative
charges remains constant.
(2) Net positive charges = net negative charges