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Electricity Notes

(If you are down loading these off of the Internet you
should look up the symbols and the schematics for series and parallel circuits.)

Electrical Symbols
Know the symbol for a piece of wire. ___________________

Know the symbol for wires not connected.

Know the symbol for a light bulb.

Know the symbol for a resister.

Know the symbol for a 10-volt DC battery.

Know the symbol for an open switch (off).

Know the symbol for a closed switch (on).

Know the symbol for a fuse.

Definitions:

A fuse is a safety device that

stops the flow of electrons. It is always placed in series so the electrons have to go through it. Never buy a "bigger" fuse than what you need.

A circuit breaker is like a fuse except

that it acts like a switch and can be reused after being tripped.

Another name for current is	is amperage; there are two kinds of current (AC and DC).
1.)Direct Current (DC) flows	in one direction from negative to positive. Electrons flow.
2.) Alternating Current (AC) flows	back and forth between positive and negative. Electrons flow.

Another name for resistance is

ohms.

A resister is anything that

opposes current flow. Light bulbs, radios, TV, etc. are examples.

A rheostat is a device that varies the

resistance - like the pencil lead lab that change the brightness of the light bulb.

A potentiometer is a device that varies

the voltage - like the lab that had three batteries that change the brightness of the five light bulbs.

Conductors are things that	conduct the flow of electron. Gold, silver, and copper are your better ones; gold is the best.
Insulators are things that	do not conduct current flow. Plastic, wood, and rubber are common examples of them.

A series circuit has

one path for CURRENT flow. If one thing is open, then everything will go off. Example = a string of cheap Christmas lights may all go out if just one bulb is not working.

A parallel circuit has

two or more paths for CURRENT flow. If one path is open, the electrons will just use another path. Example = if your house has one light go out, most of your house will still have power.

Magnets and Motors

A magnet has a north pole and south pole that point toward the Earth's magnetic north pole or magnetic south pole of the earth, not toward the "true" north or south pole.

A magnet is surrounded by	a magnetic field.
Like poles (ex. = north and north)	of different magnets repel each other.
Opposite poles (ex. = north and south)	of different magnets attract each other.
An electromagnet can	drop the magnetic field, unlike a permanent magnet, and can be made very strong.
Electrons are arranged	into lines of magnetic. They are aligned into straight rows, not in random.
Motors get spinning by	attracting and repelling magnetic fields.
An electroscope	detects magnetic fields. It has foil leaves that repel each other when charged.

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