Basic Electrical Theory Questions- EASY

[Paul W. Abernathy]

I don't think the powers that run this board want me anywhere near helping out in that fashion. I am here to help when needed and I will post quizes and information to help...until they kick me off I guess...lol

[Patrick Bolliger]

Ok all you electrical hot shots..
What is "Coulomb's Law" ? What does this have to do with electricity?

Also: Do we really get 120/220 Volts at our home? Does RMS mean anything and what really is peak to peak voltage?

Electron flow or conventional flow ...What is what?

[Bob Badger]

Originally Posted by pbolliger

What is "Coulomb's Law" ?

Like charges repel, unlike charges attract.

What does this have to do with electricity?

Never really thought about it but off the cuff I would say it is the basis for the 'flow' of electricity.

Also: Do we really get 120/220 Volts at our home?

Not in the US.

In the US you get 208/120 or 240/120.

Does RMS mean anything

Root Mean Square.

The root-mean-square of a variate X, is the square root of the mean squared value of X

In this case it is the square root of the mean squared value of a voltage reading.

what really is peak to peak voltage?

That is quite literally the voltage measurement from the 'top' to the 'bottom' of an AC sine wave.

If you measure a '120 volt' outlet with a 'scope you will see about 180 volts peak to peak.

Electron flow or conventional flow ...What is what?

You stumped me there.

A note on true RMS multimeter's they are nice to have but not necessary for residential work. True RMS meters are need when the frequency of the voltage is other than 60 cycles, which in industrial work is often the case.

[Paul W. Abernathy]

Originally Posted by pbolliger

Ok all you electrical hot shots..
What is "Coulomb's Law" ? What does this have to do with electricity?

Also: Do we really get 120/220 Volts at our home? Does RMS mean anything and what really is peak to peak voltage?

Electron flow or conventional flow ...What is what?

Coulomb's Law

Like charges repel, unlike charges attract.


The electric force acting on a point charge q1 as a result of the presence of a second point charge q2 is given by Coulomb's Law:

where ε0 = permittivity of space


Note that this satisfies Newton's third law because it implies that exactly the same magnitude of force acts on q2 . Coulomb's law is a vector equation and includes the fact that the force acts along the line joining the charges. Like charges repel and unlike charges attract. Coulomb's law describes a force of infinite range which obeys the inverse square law, and is of the same form as the gravity force.

Electric Potential Energy
Just like in the gravitational case, the potential falls proportional to r-1. The form of the potential energy U looks the same as the that for the force F except for the power of r.

Again, note that the potential energy is positive when the two charges have the same sign and negative otherwise. Note that the potential energy of a set of charges, qa,qb,...qzis the sum of the potential energies of the pairs. For instance, if there are 3 charges, qa,qb,qc, the net potential energy is:

Electrostatic charging


Forces between two electrically-charged objects can be extremely large. Most things are electrically neutral; they have equal amounts of positive and negative charge. If this wasn¹t the case, the world we live in would be a much stranger place. We also have a lot of control over how things get charged. This is because we can choose the appropriate material to use in a given situation.
Metals are good conductors of electric charge, while plastics, wood, and rubber are not. They¹re called insulators. Charge does not flow nearly as easily through insulators as it does through conductors, which is why wires you plug into a wall socket are covered with a protective rubber coating. Charge flows along the wire, but not through the coating to you.
Materials are divided into three categories, depending on how easily they will allow charge (i.e., electrons) to flow along them. These are:

• conductors - metals, for example
• semi-conductors - silicon is a good example
• insulators - rubber, wood, plastic for example

Most materials are either conductors or insulators. The difference between them is that in conductors, the outermost electrons in the atoms are so loosely bound to their atoms that they¹re free to travel around. In insulators, on the other hand, the electrons are much more tightly bound to the atoms, and are not free to flow. Semi-conductors are a very useful intermediate class, not as conductive as metals but considerably more conductive than insulators. By adding certain impurities to semi-conductors in the appropriate concentrations the conductivity can be well-controlled.
There are three ways that objects can be given a net charge. These are:

1. Charging by friction - this is useful for charging insulators. If you rub one material with another (say, a plastic ruler with a piece of paper towel), electrons have a tendency to be transferred from one material to the other. For example, rubbing glass with silk or saran wrap generally leaves the glass with a positive charge; rubbing PVC rod with fur generally gives the rod a negative charge.
   
2. Charging by conduction - useful for charging metals and other conductors. If a charged object touches a conductor, some charge will be transferred between the object and the conductor, charging the conductor with the same sign as the charge on the object.
   
3. Charging by induction - also useful for charging metals and other conductors. Again, a charged object is used, but this time it is only brought close to the conductor, and does not touch it. If the conductor is connected to ground (ground is basically anything neutral that can give up electrons to, or take electrons from, an object), electrons will either flow on to it or away from it. When the ground connection is removed , the conductor will have a charge opposite in sign to that of the charged object.

An example of induction using a negatively charged object and an initially-uncharged conductor (for example, a metal ball on a plastic handle).
(1) bring the negatively-charged object close to, but not touching, the conductor. Electrons on the conductor will be repelled from the area nearest the charged object.
(2) connect the conductor to ground. The electrons on the conductor want to get as far away from the negatively-charged object as possible, so some of them flow to ground.
(3) remove the ground connection. This leaves the conductor with a deficit of electrons.

(4) remove the charged object. The conductor is now positively charged.

BRAIN FREEZE ALERT............................

[Paul W. Abernathy]

P.S...If you really want to learn some NEAT stuff...click on the links in the above posting.....That learning site is awesome.

Ok..How does this apply to Home Inspectors.....If you do not know the basics of electricity.....you simply can't say you have a background in Electricity when it come to home inspections....these are basic principles plus it is just plain fun...who wants to look at violation picture all the time.

[jtedesco1]

http://hyperphysics.phy-astr.gsu.edu/

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

[Paul W. Abernathy]

lol...Joe I think I posted most of those up above....and BOY did it take up space..thehehe

[Paul W. Abernathy]

because these tests are freely anywhere so the answers can be found.....they would need to be original.........Joe might be able to come up with some...what do you think JOE T........you seem to like this post !!

[jtedesco1]

Audel Practical Electricity

ISBN: 0025845616
Author: Robert Gordon Middleton L. Donald Meyers Joseph A. Tedesco
Publisher: Audel
Edition: 4
Date published: 1988-07-29
Format: Paperback
Number of pages: 512
All Editions Similar Books

Electrical Courses for Apprentices and Journeymen

ISBN: 0025945505
Author: Joseph A. Tedesco
Publisher: John Wiley & Sons Inc
Edition: 3
Date published: Jun 1988
Format: Hardcover
Number of pages: 471
All Editions Similar Books


I will try to remember?

[Paul W. Abernathy]

lol.......hmmmm...are you saying those that do not have the time or desire to ab author do not know anything...lol.......I JUST might surprise you old man....

[Paul W. Abernathy]

relax.....I call my dad old man also.....thehehehe

[Richard L. Bennett]

Anyone spot the errors in Bob Badgers post??

rlb

[Jay Moge]

well of couse.............not.

[Paul W. Abernathy]

Considering he is NOT here to defend himself......pointless

[Patrick Bolliger]

Paul ,

You win a "stuffed animal" prize here at the carnaval...

Now for our final questions.........

What works on zero Hertz?

and our million dollar question:

What is the "string" theory?? Sorry ha ha ha ha