BASIC ELECTRONICS - OD1633 - LESSON 1/TASK 1
stated by Ohm's law, and provide examples of applying Ohm's law to a basic
a. Amperage (Current) and Voltage.
(1) Amperes. Current flow, or electron flow, is measured in amperes
While it is normally considered that one ampere is a rather small
current of electricity (approximately what a 100-watt light bulb would
draw), it actually involves a tremendous flow of electrons. More than six
billion electrons a second are required to make up one ampere.
Electrons are caused to flow by a difference in
electron balance in a circuit; that is, when there are more electrons in one
part of a circuit than in another, the electrons will move to where they are
This difference in electron concentration is called potential
difference or voltage (E). The higher the voltage, the greater the electron
imbalance becomes. The greater this electron imbalance, the harder the push
on the electrons (more electrons repelling each other) and the greater the
current of electrons in the circuit.
When there are many electrons
concentrated at the negative terminal of a generator (with a corresponding
lack of electrons at the positive terminal), there is a strong repelling
force on the electrons moving in the wire.
This is exactly the same as
saying that the higher the voltage, the more electric current will flow in a
circuit; all other things, such as resistance, being equal.
b. Resistance. Even though a copper wire will conduct electricity with
relative ease, it still offers resistance to electron flow. This resistance
(R) is caused by the energy necessary to break the outer shell of electrons
free, and the collisions between the atoms of the conductor and the free
It takes force (or voltage) to overcome the resistance
encountered by the flowing electrons. This resistance is expressed in units
called Ohms. The resistance of a conductor varies with its length, cross-
A long wire offers more resistance than a short wire of the same cross-
sectional area. The electrons have farther to travel.