The document discusses the basic concepts of electricity including direct current (DC), alternating current (AC), voltage, resistance, and circuits. It explains that DC flows in one direction while AC periodically reverses direction, and that AC is easier to transmit over long distances due to transformer capabilities. The basic components of an electric circuit are also defined as the load, supply, and switch.

1. Computer Hardware and Servicing
Lesson 4, Module 4
MA. RACHEL B. ESPINO
Buhatan National High School
Purok Marcos, Buhatan, Sorsogon City

2.  Electricity is define as the
flow of electron or electric
current. It is an invisible
form of energy that can be
transform into other form of
energy like heat light and
mechanical.

3.  Electron is the negatively
charge component of an
atom. It has the ability to
flow.

4.  Proton is the positively
charge component of an
atom. It had the ability to
attract electron.

5.  Matter is anything that
occupy space and has
mass. It can be a solid,
liquid or gas in state.

6.  Atom is the basic
component of matter. It
composes of a nucleus
which is the central part, the
protons and electrons.

7.  Current same as electricity
or flow of electron. The
amount of current flowing in
a circuit can be measured in
ampere (I).

8.  Voltage is the amount of
pulling force that makes the
electron flow. Also known as
potential difference or
EMF(electromotive force).
The amount of voltage can
be measured in volt (V).

9.  Resistance is define as the
opposition to the flow of
current. The amount of
resistance can be measure
in ohms (Ω).

10.  Conductors are materials
that easily allow the flow of
current, or it has a low
resistance to current flow.
Examplesaluminum, gold,
silver, copper, iron

11.  Insulators are materials that
do not easily allow the flow
of current, or it has a high
resistance to current flow.
Examples; rubber, plastic,
paper

13.  In direct current (DC), the
flow of electric charge is
only in one direction. This is
the type of electricity is
produced by batteries,
static, and lightning. A
voltage is created, and
maybe stored, until it is
consumed. The current
flows directly, in one
direction.

14.  In the circuit, the current flows
at a specific, constant voltage
(this is oversimplified
somewhat but good enough
for our needs.) When you use
a flashlight, pocket radio,
portable CD player or virtually
any other type of portable or
battery-powered device, you
are using direct current.

15.  Most DC circuits are
relatively low in voltage; for
example, your car's battery
is approximately 12V, and
that's about as high a DC
voltage as most people ever
use.

16.  Direct currents flow in one
direction only, and are
constant in time. Their
appearance is that of a
straight line which does not
vary. They are produced
from power sources such as
batteries, power supplies
and DC generators.
Photovoltaic devices such as
solar cells also generate DC
power.

18.  In alternating current (AC,
also ac) the movement of
electric charge periodically
reverses direction. This type
of electricity is produced or
generated by AC generators
commonly from a hydro
electric plant. It is the
commercial power that we
use in homes and offices

19.  Delivered through a power
transmission lines, AC
current can be reduced
through the use of power
transformer to suite for its
application. It can also be
converted to DC for a
specific purpose. In the
Philippines AC is rated as
220V AC at 60 Hz.

20.  Alternating currents change
direction, flowing first one
way and then the other. They
are sinusoidal waves, so that
they change in time. They are
produced from sources such
as power supplies and AC
generators.

21.  In North America, AC is 120
volts and 60 hertz or cycles
per second. This means it
changes direction 60 times
per second. In Europe, it is
generally 50 hertz with 220
to 240 volts.

22.  There are a number of
reasons, but one of the
most important is that a
characteristic of AC is that it
is relatively easy to change
voltages from one level to
another using a
transformer, while
transformers do not work
for DC.

23.  This capability allows the
companies that generate
and distribute electricity to
do it in a more efficient
manner, by transmitting it
at high voltage for long
lengths, which reduces
energy loss due to the
resistance in the
transmission wires.

24.  Another reason is that it
may be easier to
mechanically generate
alternating current
electricity than direct
current.

25.  PC’s use only direct
current, which means that
the alternating current
provided by your utility
must be converted to
direct current before use.
This is the primary
function of your power
supply.

27.  Electric circuit - is the
pathways for electricity to
flow.

28. 1. Load - commonly
represented by a bulb or
any electrical component
that consumes electricity.
2. Supply - Commonly
represented by a cell or a
battery
3. Switch - an electrical device
that opens or closed a
circuit.

29. SWITCH

30. 1. Open Circuit - a
type of circuit that
has an open path for
current to flow. It
means that current
cannot flow in open
circuit.
The switch is said to be
“OPEN” the current can’t
flow into the circuit and
the bulb is “OFF”

31. 2. Closed Circuit - a
type of circuit that
has a closed path for
current to flow. It
means that current
can flow in a closed
circuit.
The switch is said to be
“CLOSED” the current can
flow into the circuit and the
bulb is “ON”

32.  Identify what is being
described in the following
statements.