[16] E.g., see Robert L. Shrader, Electronic Communication,
Sixth Edn., MacMillan/McGraw-Hill, New York, NY, 1991.
(1993 Imprint). Quoting from p. 6: "A source of electric
energy does not increase the number of ~ree electrons in a
circuit; it merely produces a concerted pressure on any
aimlessly moving electrons."