In our modern world, the easiest and most
efficient way of distributing large amounts
of energy is through electricity.
Electricity is made up of positive and negative,
static and moving charges, like protons and
electrons.
These repel similar charges and attract their
opposites.
Pushing like charges together or pulling opposite
charges apart takes work, which stores electrical
potential energy in the form of a field between
them.
This potential energy is released when we
allow the charges to move together, or to
push apart.
The amount of field energy acting on individual
charges in an area is called the electric
potential.
The difference in electric potential between
two isolated areas is called the potential
difference, and is measured in volts.
If we connect the two areas with a material
that allows charges to flow, we make a circuit.
Charges will be pushed and pulled through
the circuit in an attempt to balance the fields.
We call this movement an electrical current,
and measure it in amperes, or amps.
The amount of current flow, multiplied by
the potential difference between the two points,
is equal to the amount of power being moved
or used, and is measured in watts.
One amp flowing though a potential difference
of one volt delivers one watt of power.
Current can flow through a circuit in only
one direction at a time.
If that current always flows in the same direction,
it’s called a direct current or DC.
But, if it regularly changes directions it’s
called an alternating current or AC.
The voltage of an alternating current looks
like a wave, and has a frequency, an amplitude
and a phase when compared to other AC flows
of the same frequency.
All materials oppose the flow of charges,
at least a little bit.
This opposition, called resistance, is measured
in ohms.
Special items, called loads, resist the current
flow in a way that extracts the current’s
power.
Resistors, Inductors, and Capacitors are three
types of loads that form the basic building
blocks of most circuits.
Resistors convert electric power into heat
or light, inductors store power as a magnetic
field, and capacitors store power as an electrostatic
field.
Since the current flowing into and out of
the circuit must be the same, the energy removed
reduces the voltage across the load.
This is a loss of one volt for every one amp
crossing a one-ohm resistor.
Power loss through capacitors and inductors
is more complicated because their behavior
depends more on how the circuit is set up.
Resistors usually act the same way for both
AC and DC power, while capacitors and inductors
don’t.
Capacitors briefly allow direct current to
pass through them as they build their electrostatic
field, before building a high resistance to
the flow.
Inductors are the opposite, temporarily stopping
the flow of direct currents as it builds its
magnetic field, before letting it pass.
Alternating current is constantly changing
flow directions, and if it’s frequency is
high enough, it passes through a capacitor
with little distortion.
On the other hand, higher frequencies make
it harder for AC to flow through inductors,
as the inductor’s magnetic field has to
continually change directions.
Fortunately, a changing magnetic field also
induces a current in nearby wires, allowing
inductors to transfer power through magnetism,
and making things like transformers, motors
and radio possible.
While there are a lot of other parts that
can make up electric circuits and important
fancy equations that describe what’s going
on in better detail, these fundamental pieces
form the bulk of how we interact with electricity
on a daily basis, making them the basic facts
about electricity that everyone should know.
For Tech Laboratories, I’m Tech Adams, saying
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