DC Fundamentals Unit 4 – DC Power Sources
Unit 4 – DC Power Sources .........................................................................................................
UNIT OBJECTIVE
At the completion of this unit, you will be able to demonstrate battery circuits by using the DC
FUNDAMENTALS circuit board.
UNIT FUNDAMENTALS
A basic source of electricity with which almost everyone is familiar is the battery. Although
batteries come in many types and sizes, two of the most common types are the storage battery,
used in automobiles, and the dry cell, used in transistor radios and flashlights.
Examples of battery types and voltages are carbon-zinc or alkaline (1.5 Vdc), nickel-cadmium
(1.25 Vdc), and lead-acid (2 to 2.2 Vdc).
A battery is composed of two or more voltaic cells. A cell is one unit consisting of a positive and
negative plate.
A battery is normally composed of two or more cells that are assembled in a single working
package. Cells can be classified as primary or secondary. A primary cell, such as a carbon-zinc
dry cell, cannot be recharged. Secondary cells, such as automobile batteries, can be recharged.
When cells or batteries are connected in series (positive to negative), their voltages are added,
and current is the same through each.
IT = I 1 = I 2