for Education and Industry
Electricity 101 is an interactive computer program that
will give you an intrinsic understanding of electricity through
the use of text, graphics, animation, and sample problems.
No prior knowledge of electricity is assumed or required.
You can benefit from this program if...
- You simply want to know more about electricity.
- You need an understanding of electricity for your job, such as
a project manager, purchasing agent, or researcher.
- You need to be able to communicate with electricians,
electrical contractors, engineers, or technicians.
- You know something about electricity but need to "fill in the
gaps" and get a better understanding.
- You want to start a career path in an electrical field and
need a foundation for further study in your chosen field.
Here is the Table of Contents of the program...
Table of Contents
Why study electricity?
What do I care about electrons?
Where do I go from here?
2. What Is Electricity?
What is an electron?
What is a valence electron?
What makes a good conductor of electricity?
3. How Does Electricity Flow?
What makes electrons move?
How do electrons move?
Where do electrons go?
4. How Is Electricity Made?
What are the 6 Categories of Electricity?
5. How Is Electricity Measured?
What is an amp?
What is a volt
What is resistance?
What is Ohm's Law?
What is a VOM?
How is a VOM connected to measure volts, amps, and ohms?
6. What is AC and DC?
What is DC?
What is AC?
What is Frequency?
What is Hertz?
What is RMS?
What is a Sinewave?
What is 3 Phase AC?
7. How Is Electricity Sold?
What are Watts?
What are Kilowatt-Hours?
8. What Are Some Types of Circuits?
What is an Open Circuit?
What is a Short Circuit?
What is a Series Circuit?
What is a Parallel Circuit?
9. How Is Electricity Made Safe?
How Much Electricity is Dangerous?
How Can We Protect Against Lightning?
How Can We Protect Against Short Circuits?
What Is a fuse?
What Is a Circuit Breaker?
What Is a GFCI?
What Is an AFGI?
Why are some wires bigger than others?
10. How is My House Wired?
What is a transformer?
What is a panelboard?
What is a single-pole breaker?
What is a two-pole breaker?
Why doesn't that bird get electrocuted?
Electricity 101 is written in .html format so you can use
your favorite internet browser to navigate through it using
hyperlinks, bookmarks, and word searches. Electricity 101
requires no software installation on your computer. Just
double-click on the Table of Contents.html.
Electricity 101 is written by a Professional Engineer with 14
years industrial experience and 20 years experience teaching
electrical engineering technology at the college level.
Following are some sample screens shots from Electricity 101...
...part of Chapter 5.
How Is Electricity Measured?
The next picture shows a VOM connected to check for "continuity".
The meter is placed in the Ohm reading position, usually on the most
sensitive (smallest resistance) scale. A continuity test is
performed to determine if there is a continuous path for electricity
to flow between two points. This is useful, for
instance, to trace a wire in a circuit, to check if a wire is
broken, to check if contacts are closed, or to check if a fuse is
If the wire, contact, or fuse is intact, the VOM will read virtually
zero ohms, since a piece of wire, good contact, or good fuse has
very little resistance. You would get the same result if
you touched the two leads of the meter together.
If the wire, contact, or fuse is broken, the VOM will read
extremely high resistance because the air gap at the break has very
high resistance. The extremely high resistance is usually
indicated by "O.L." on a digital meter, meaning "overload", because
the resistance is higher than the meter can indicate. You
would get the same result if you simply held the two leads apart in
the air, since the resistance of air is very high (i.e.: air is not
a very good conductor of electricity, except in the presence of an
extremely high voltage such as lightning or a high voltages arc).
...part of Chapter 9. How Is
Electricity Made Safe?
What is a Ground Fault Circuit Interrupter (GFCI)?
There are some electrical faults that a fuse or circuit breaker
cannot protect against. For instance, fuses and circuit
breakers in a home usually have a 15 amp or 20 amp current
rating. An electrical circuit may have a small "leakage"
current to ground, called a "ground fault", that is not enough
current to trip the fuse or circuit breaker. But if you get in
the path of the leakage current it can travel through your body on
the way to ground and cause injury or death. We saw in the
table at the beginning of this chapter that a current as low as
0.075 amps can cause heart fibrillation. The chances of the
leakage current passing through you to ground is increased if you
are in contact with water, thereby decreasing your resistance to
ground. For this reason, devices called Ground Fault Circuit
Interrupters (sometimes just called Ground Fault Interrupters or
GFIs) are required by the National Electrical Code in locations
where water is present, like bathrooms or outdoor receptacles.
Ground Fault Circuit Interrupters can be built into convenience
outlets, circuit breakers, or portable power cords for use on
construction sites as shown below.
Regardless of their packaging, GFCI's work by comparing the amount
of current that flows from the receptacle or circuit breaker to the
load with the amount of current that flows back from the load.
If the two currents don't match, then some current must be leaking
to ground through a ground fault, and the GFCI trips to remove power
from the circuit.
It is interesting to note that some motor driven equipment like
freezers are exempt from GFCI requirements because they inherently
have leakage current to ground, and use of a GFCI would result in
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