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Watts - How do you compute the
number of watts? Easy, just multiply the number of volts times the
number of amps, and that's the number of watts.
Here' s an example: you plug a lamp
into the 12-volt line in your wall, and it draws 1 amp of current
through the light bulb. How many watts does it use?
120(volts) x 1(amp) = 120(watts)
That's right, it's a 120-watt bulb.
If you replaced it with a 60-watt bulb, that one would use only 1/2
an amp.
120(volts) x 1/2(amp) = 60(watts) |
Circuit
Electricity flows readily in some
materials but not in others. Some conduct electricity readily;
they are of course called
conductors.
Typical good electrical conductors include copper, aluminum, gold
and other metals, and water. Materials that do not conduct
electricity are called
insulators.
Common insulators include wood, glass, plastic, and air.
However, any substance, even one that normally insulates so well as
to stop the flow of electricity, will conduct electricity if the
charge is strong enough-even the air.
What material conducts electricity in the air?
Why
is jewelry an important factor concerning a circuit?
What would happen if a screw fell on a powered computer?
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Direct current
- Abbreviated "DC"
- Produced by batteries, static,
and lightning.
- Specific, constant voltage
- Usually a portable or
battery-powered device
- DC circuits are relatively low
in voltage
What current
does a PC use?
What are some devices that use DC for power? |
Alternating current
-
Abbreviated "AC"
- produced by power companies
- fluctuating power (low to high
then high to low)
- Power usually comes from a
socket
- Can change voltage using a
transformer
- Can generate extremely high
voltages
What is the standard voltage for
a AC socket? |