TABLE OF CONTENTS Modern electronic circuitry requires direct current for operating semiconductor devices. This direct current can be obtained from linear or switching power supplies, batteries, solar cells, or even fuel cells. This section covers the principal practical means for obtaining DC power at voltages that are typically less than 50 V The technical definition of a battery is two or more power cells connected in series to provide an output voltage that is the sum of the voltages of the individual cells. But battery manufacturers' literature and consumer advertising, as well as the general public, typically refer to both 1.5-V C cells and 9-V alkaline batteries as batteries. This section distinguishes between the two electrochemical power sources.
A battery is an assembly of two or more electrochemical power-producing cells. The power cell consists of four principal components:
Anode or negative electrode (a reducing material or fuel)
Cathode or positive electrode
Oxidizing agent
Electrolyte which provides for internal ion transfer
Electrolytes are usually liquid, but some cells have solid electrolytes. In addition, there is a material separating the anode and cathode.
The cell converts the chemical energy within its active materials directly into electric energy by an oxidation-reduction process. The anode gives up electrons during cell discharge in an oxidation reaction and electrons are transferred from one material to another. The anode is separated from the cathode, which is capable of accepting electrons. Electrons flow in the external circuit connecting the anode and cathode through the electrolyte to...
