4Voltage and Current: Direct and Alternating Current and Voltage
4.1 Introduction
In the last chapter we have described the characteristics behind difference in electric potential, electric fields, and current.
In this chapter, we will describe direct current (DC) and alternating current (AC) and voltage.
4.2 Terminology
The term “direct current” is used indiscriminately to refer to direct voltage and to direct current. In this book we will differentiate the terms to prevent confusion. The same thing is valid for “alternating current,” which in the real world is used to refer to both alternating voltage and alternating current.
Other terms also used are VDC to refer to “DC voltage” or direct (continuous) voltage and VAC to refer to “AC voltage” or alternating voltage.
4.3 Batteries
Around 1800, Alessandro Volta reported the results of an experiment where he was able to create electricity by piling discs of zinc and copper separated by felt spacers soaked in salt water. With this invention, Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings.
A new invention was born: the battery.
4.3.1 Battery Life
Batteries are electrochemical devices created by embedding two different metallic plates into a third one. This third one, the electrolyte, is responsible, broadly speaking, for creating a ...
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