4. Drafting
The process of drawing to communicate ideas and
instructions to others.
Most manufactured products and all major buildings
were first created on drawing boards
5. Drafting Equipment
T square –instrument used in drawing horizontal lines. It is also used
in guiding triangles when drawing vertical lines.
Triangle – a three sided ruler which has typically two equal sides
meeting at 900.
30 x 60 and
45 x 45 degrees.
Divider - is used to create equal distances, transfer measurements and
spacing points or lines
Masking tape - material used for fastening the drawing paper on the
drawing table.
Erasing Shield - is a useful tool to protect the rest of the drawing when
clearing up smudges, unnecessary pencil lines and other erasures.
Pencil - is made of a much better grade of graphite, commonly called
lead which is used in drawing lines. (9H, 8H, 7h, 6H, 5H, 4H, 3H, 2H,
H, HB, B, 2B, 3B, 4B, 5B, and 6B)
6. Drafting
Freehand drawing or Sketching – the use of pencil,
paper and eraser only.
Mechanical drawing – describing the shapes of objects
completely and exactly with the aid of drawing instruments
and by the use of orthographic projection.
Technical Drawing – used to show the material, dimension
(Width, Height, Depth) and shape of a product.
Orthographic Drawing– representing the exact shape of an
object into 2 or more views on planes, generally at right angle
or 90 degrees.
Isometric drawing – the object is represented by three sides
seen at one time. It is made with a 30 x 60 degrees triangle.
Pictorial drawing – it shows object as it would appear in a
photograph. It shows more than one side of the object.
7. Lettering (Free Hand)
Lettering is usually done freehand
Either one of these two styles may be made; vertically or
inclined.
Italics is 67.5 degrees
A good height of lettering for dimension and notes on a working
drawing is 1/8 of an inch.
For the lettering of subtitles 3/16 of an inch is recommended.
All titles should be lettered with capital letters.
When only capital letters are used, the beginning letter of each
sentence is often made higher than the remaining letters.
When lower case letters are used, capitals are used in the
beginning letter at the start of a sentence, and for proper names,
8. Lettering (Guidelines)
[1]Cap line – the uppermost line for uppercase letters
and for ascender.
[2]Waist line – line between Cap and Base lines, used
to determine the height of the lower case letters.
[3]Base line – line where all the letters rest or stand.
[4]Drop line – a line for letters with strokes that
extend downward known as descender.
Day
[1]
[2]
[3]
[4]
9. Drafting (Kinds of Letters)
Gothic – all letters are composed of uniform width
elements
ABCDEF abcdef
Roman – letters have strokes (accented), or made up
of thick and thin elements
ABCDEF abcdef
Text – elements are made with style C or D speedball
pens. Old English, church text.
ABCDEF abcdef
10. Drafting (Lines)
[1]Dimension line - used to indicate the measurement of objects
which are represented by dark solid lines.
[2]Extension line – fine line used to show clearly the dimension
limits.
[3]Center line – light broken lines used in circles, sometimes as
extension line
[4]Leader line – line leading from a dimension value, or explanatory
note to the feature on the drawing. An arrowhead is used in pointing
end but not in note end.
[5]Long break – a limiting line used to limit the length of elongated
object.
[6]Invisible line - a series of light dash line that represents parts of a
drawing that are not seen.
Border line - is considered as the darkest lines that surround a
drawing usually in rectangular shape
12. Drafting (Isometric Drawing)
It presents the object in 3 views, FV, TV and RSV.
Three axes are needed to perform isometric drawing, the vertical axis,
left 300 axis and right 300 axis (a=1200 , b=1200 , c=1200 )
The drawing that has equal measure.
The BOX method is the starting point of isometric drawings.
a
b c
13. Drating (Pictorial Drawing)
Axonometric Drawing – the object turned so that three faces
are viewed simultaneously
Oblique Drawing
a pictorial drawing having one side parallel to the picture plane. It
maybe drawn at any convenient angle.
Types of Oblique drawing
Cavalier –the width, depth and height is the true length or size (Actual
representation)
Cabinet –the depth is reduced to one half. The front is actual size,
while the depth of top and right side are drawn one half to the actual
Perspective Drawing – the most realistic, the object is drawn as it
seen by the naked eye.
One point drawing (Vanishing Point)
Two points drawing
VP
15. Sample Question 1
a
b c
A.) Perspective
B.) Isometric
C.) Orthographic
D.) Technical
16. Sample Question 2
This is a kind of letter in lettering where letters have
strokes (accented), or made up of thick and thin elements
ABCDEF abcdef
A.) Gothic
B.) Roman
C.) Text
D.) Old English
17. Sample Question 3
This is a series of light dash line that represents parts
of a drawing that are not seen.
A.) Dimension Line
B.) Leader Line
C.) Invisible Line
D.) Center Line
19. Carpentry
Carpentry is the term commonly referring to
technology and science of cutting, fitting, and
assembling related materials in the construction of
boats, bridges and piers, or any other structure made
from construction materials.
21. Carpentry (Types of Woods)
Lumber - woods that came from trees, either softwood or
hardwood.
Yard Lumber – prepared lumber for variety of uses. Select
and common
Softwood – it comes from the evergreen or needle bearing
trees. These are called conifers because many of them bear
cones.
Hardwood – it comes from broad leafed (deciduous) trees
that shed their leaves at the end of the season.
Select grade – is lumber of good appearance that can take
different finishes such as stain, paint, and enamel.
Common grade – it is suitable for rough carpentry. It is
not of finishing quality. (eg. Coco Lumber)
22. Carpentry (Parts of a Wood)
Sapwood – the part of the wood that is close to the
bark
Heartwood – inner part of the wood which is made up
of accumulated dead cells.
Cambium layer – a thin layer that divides the inner
part of the wood and the bark.
23. Carpentry (Lumber Defects)
Split or Check is a lengthwise separation of the wood
along the grain like small crack or split
Knot is a branch or limb of a tree that has been
exposed when the log is cut.
Pitch Pocket – internal cavity that contains resinous
materials. (usually attracts ants)
Stain – discoloration of the wood surface
Shake – separation between the annual growth rings.
24. Carpentry (Quality of wood)
S2S – planed or smooth on two sides
S4S – planed or smooth on four sides
25. Carpentry (Unit of Measurement of wood)
The unit of measure for lumber is “board foot”.
(T” x W” x L’ )/ 12
How many board feet are there in 7 pieces of 2” x
4” x 12’ lumber?
56 bd. ft.
26. Carpentry (Wood Preparation)
Seasoning – the process of drying the wood in
preparation for use.
Air Seasoning (Sun Dried) – filling the wood in open air
Kiln Seasoning (Kiln Dried) – the used of oven to dry wood
Treated – Use of Chemical compound before seasoning
The approximate moisture content of drying
hardwood for home furniture is
20 % for softwood, 6-12 % for hardwood
27. Carpentry (Finishing)
Scraper is tool made of steel. It is used to produce a very smooth
surface.
Wood Fillers - this are used to eliminate deep cuts and holes in your
finished project, so that surface can be made even and smooth.
Stain - is a wood finishing material; derived from different color of
woods such as walnut, mahogany and natural color.
Shellac - a finishing material came from gums substance of insects.
Varnish - a finishing material when applied produces high glossy
finish to a project. It came in different forms, from gum, linseed oil,
resin, turpentine and or chemical drier.
28. Carpentry (Joints)
Joinery is the process of putting the work together.
Butt joint – the end of one piece is fastened to the surface or edge of other piece.
Milter joint – the corners are cut usually at 45 degrees and joined forming right
angle.
Dovetail – used on the corners of drawers and chairs. (“Kaltas”)
Mortise and Tenon – is one of the strongest joint used for quality chairs, tables and
benches. (Force Fitting)
Dado - is a groove that runs on board and receives the end or edge of the second
board. (“TnG”)
Rabbet - is a wood joint commonly used for making frames to hold glass in
constructing drawers and other cabinetwork.
29. Carpentry (Tools)
Push Pull Steel Tape Rule - steel tape is assembled in a fixed casing and
retracts automatically by spring.
Try Square - is use for testing the squareness of two surfaces.
Sliding T Bevel - this tool can be set to lay out any angle.
Marking gauge – it is used in laying out and marking the thickness and width
of stock.
Knife is used when you know that the marks will disappear.
Scratch awl is used to lay out positions for drilling and boring holes.
Dividers are used for dividing space equally, transferring measurements and
scribing arcs and circles.
30. Carpentry (Holding Tools)
Vise is used for holding a work of piece to allow work to be performed in it.
Clamp is used for gluing up large surfaces, edge to edge and for clamping parts
together when assembling projects.
Brace – it is used for holding auger bits, fastener bits and other tools with
rectangular shape shanks.
31. Carpentry (Cutting Tools)
Long crosscut saw – it is used in cutting large and round timber.
Rip saw – it is designed in sawing along the grain.
Crosscut saw – it is designed in cutting across the grain. The shape of
the teeth is similar to knife blades.
Backsaw – it has stiff blades for more accurate work both on the bench
and the vise.
Hack saw – is used to cut metal.
Coping saw – used in cutting irregular shapes.
Keyhole saw – used in cutting circle shape in a wood.
32. Carpentry (Smoothening Tools)
Plane - it is used in reducing the thickness or width of a piece of wood
and for smoothing surfaces
Spokeshave – it is used to plane convex and concave edges.
Chisels and gouges – it is used in cutting edge and carving of woods.
33. Carpentry (Boring Tools)
Auger bits – it is designed for boring holes in woods.
Brace – it is used for holding auger bits and other tools with rectangular
shape shanks.
Drill – a set of twist drills used for drilling both metal and wood.
Gimlet – it is a small brace bit fitted with a box wood handle. It is used
in boring holes with small diameter.
34. Carpentry (Driving Tools)
Mallet – it is made of wood and it is used in driving chisels with
wooden handles.
Claw Hammer – it is used in driving and pulling nails.
Ball Peen Hammer – it has a round knob at the back of the hammer. It
is used in metal work.
35. Carpentry (Roofs)
Gable Roof. This roof has two roof slopes that meet at the center
(ridge), forming a gable. It is the most common roof because it is
simple, economical, and may be used on any type of structure.
Hip Roof. This roof has four sides or slopes running upward toward
the center of the building to create a ridge (or peak)
Lean-To or Shed Roof. This roof used where hasty or temporary
construction is needed and where sheds or additions to buildings are
erected.
Valley Roof. This roof is framed of two intersection hip or gable roofs.
The two roofs meet at a valley.
36. Sample Question 1
What computational formula is used to compute for the
measurement of wood in board feet?
A.) (T” + W” + L’ )* 10
B.) (T” x W” x L’ )/ 10
C.) (T” - W” - L’ )/ 12
D.) (T” x W” x L’ )/ 12
37. Sample Question 2
How much will Mr. Policarpio pay if he purchase 14 pieces
of 2x2x10 of lumber and the prices per board foot is Php
12.50?
A.) Php 41.66
B.) Php 583.33
C.) Php 46.66
D.) Php 653.33
Bd.ft= (T” x W” x L’ )/ 12
Bd.ft= (2 x 2 x 10) /12
Bd.ft= 3.33
Total Amount = (3.33 Bd.ft x 14 pcs ) x Php12.50
Total Amount = (46.66 Bd.ft) x Php 12.50
Total Amount = Php 583.33
38. Sample Question 3
What kind of joint in carpentry is illustrated below?
A.) Mortise & Tenon
B.) Dovetail
C.) Milter joint
D.) Dado
40. Masonry
Masonry is the art of building with stone, bricks,
concrete blocks or similar materials.
It is the building of structures from individual units
laid in and bound together by mortar.
41. Masonry (Basics)
Concrete – the artificial stone as a result of mixing
sand, cement, gravel and water.
Mortar – mixture of cement, sand and water used for
binding stones, bricks, etc. or for plastering.
Plaster – mixture applied wet to wall or ceilings and
hardened to produce smooth surface.
Cement – a bonding agent that reacts with water to
form a hard stone-like substance.
42. Masonry (Tools)
Roughing up tools
Plumb bob is used in guiding the vertical position in
laying bricks
Water and Tube Level – use to establish level marks
in laying out masonry works
Crandall – tool with pointed steel pikes used for
dressing concrete.
Bolster – tool similar with chisel including its services
Spade – basic construction tool used in mixing
concrete.
43. Masonry (Tools)
Float – tool with handle at the back usually made of
wood.
Trowel – flat tool used for applying, spreading and
shaping plaster or mortar to produce smooth finish.
44. Masonry (Common Materials)
CHB - is the most widely used masonry material for
construction works.
Bricks – are manufactured from clay and other materials
processed into workable consistency and molded to standard
sizes.
Ashlars – carefully worked and joined stone blocks laid in
parallel horizontal courses.
Rubble stone – irregular stones with good face for wall surface.
Aggregates - the material that is bound together into a
conglomerated mass by cement and water to form concrete,
mortar or plaster.
Fine – sand
Coarse – crushed rocks, gravel .
45. Masonry (Mixing Proportion)
Cement Sand Gravel
AA – 1 : 1 ½ : 3
A – 1 : 2 : 4
B – 1 : 2 ½ : 5
C – 1 : 3 : 6
For Handmixing
½ kg of water + 1 kg of cement + 2 kg of sand + 2.5 – 3
kg of gravel
46. Masonry (Strength of Concrete)
Correct proportion of the ingredients
Quality of the materials
Proper methods of mixing
Proper placement or depositing of the concrete inside
the form
Adequate protection during the period of curing
Finding the Quantity of Cement, Sand and Gravel
It will depend on the kind of mixture (AA, A, B or C)
Find the volume
47. Masonry (Strength of Concrete)
One cubic feet of gravel is equal to 95% of the volume of
concrete
Cement is equal to
cubic feet of gravel
quantity of gravel in the proportion
Sand is equal to
cubic feet of gravel
2
Volume = T” x L’ x W’
Example: 5” x 10’ x 20’
5/12 x 10 x 20 = 83.33 cu. ft.
48. Masonry (Strength of Concrete)
How many bags of cement, sand and gravel are needed
for the construction of a concrete flooring with 5
inches thick and dimensions of 10 x 20 feet of class B
concrete mixture?
class B – 1 : 2.5 : 5
Volume = 5/12 x 10 x 20 = 83.33 cu. ft.
83.33 x 95% = 79.16 cu.ft. of gravel
79.16 / 5 = 15.83 bags of cement
79.16 / 2 = 39.58 cu.ft. of sand
Values in Red are constant (Based on Mixing prop)
49. Masonry (Strength of Concrete)
A floor 15 feet by 20 feet is to be concreted with 4
inches thick. The proportion is Class A. Find the
number of cement, sand and gravel in cu.ft.
Cement = 23.75 bags
Sand = 47.5 cu.ft.
Gravel = 95 cu.ft.
50. Masonry (CHB Quantity)
Find the area of the wall (sq. m.)
The area to 12.5 (given no. of HBs per sq. m.
with ½ “ thick mortar )
Ex. 3m x 8m = 24 sq. m. x 12.5 = 300
How many CHBs are needed for the construction of 8
meters high and 8 meters long fence?
52. Plumbing (RA 1378)
Plumbing is the art and science of installing pipes,
fixtures and other apparatus to convey and supply
water in buildings and to dispose and discharge waste
water in a safe, orderly, healthy and sanitary way.
Plumbing designs and installations are governed by a
set of rules prescribed by the National Plumbing Code.
Republic Act 1378, otherwise known as the "Plumbing
Law".
53. Plumbing (Purpose of the Code)
Establish standards that will protect the health of the
community. Faulty plumbing is a serious health
hazard.
With the increasing standardization of equipment and
materials, plumbing codes in different areas of the
country are tending more and more toward
uniformity,.
54. Plumbing (Basic Terms)
Fixture – any of the fixed plumbing items in a household such as
lavatories, showers, bath tubs, etc.
Sewer – an underground tunnel that carries off the drainage and water
matter from a house.
Fittings – are piece of apparatus, equipment or furnishing used for
pipe installations.
Drainage – includes all piping within the public or private premises
that conveys sewage, rainwater and other liquid wastes.
Vent pipe – facilitate ventilation to avoid siphonage or backflow of the
water seal.
Soil pipe – pipes that convey waste coming from water closet (toilet).
Waste pipe – conveys waste from various fixtures other than water
closet.
Solid waste – from water closet (toilet)
Liquid waste - from various fixture
55. Plumbing (Basic Terms)
Cleanout be installed in the pipe system to facilitate troubleshooting
in case of stoppage of flow
Any structure with a house drain installed, must have at least one soil
stack or stack vent extended full size above the roof.
Not less than 3” or 75mm diameter, no less than 2 m above the roof
if the roof is used other than protection from the elements of weather.
The ideal position of horizontal pipe, were those installed at 2% slope.
2 cm per 1 meter length, a 3 meters pipe will have inclination of 3x2=6
cm.
The house drain shall be provided with adequate number of cleanouts
to facilitate troubleshooting or cleaning in case of stoppage or flow.
Every 20 m space
56. Plumbing (Types of Pipe)
Rigid type
Polyvinyl chloride (PVC)
Chlorinated Polyvinyl chloride (CPVC)
Styrene Rubber Plastic (SR)
Flexible type
Polyethylene (PE)
Polybuthylene (PB)
Copper pipe – used in installing hot water supply
PVC pipes quickly installed using solvent
cementing.
57. Plumbing (The Septic Tank)
Septic Tank – is is the receptacle or vault used to collect organic waste
discharge from the house sewer.
An ideal size of septic tank is 1.3 cu.m, for 6 family members
A very large tank is not advisable because the bacterial activities would be
retarded.
Bacteriological Processes
Sedimentation process - decomposition in the upper portion of the tank
(with the scum)
Anaerobic decomposition –decompo-sition of the sludge at the bottom of
the tank.
Sludge – a semi-liquid substance accumulated at the bottom of the septic tank.
Scum – a floating substance at the septic tank.
The minimum distance required between the septic tank and residence is ten
feet (10’)
The minimum distance required between the well and septic tank is seventy-five feet
(75’)
58. Plumbing (Tools and Materials)
Pipe wrench – used in turning soft iron pipes and fittings with
rounded surface.
Wrench – is used to tighten or loosen hexagonal fittings.
Pipe vise – used in holding pipes for cutting and threading.
Threader – tools used in making teeth on pipes
Pipe cutter – used to cut pipes
Tube cutter – or pipe cutter used for thinner pipes and tubes.
Hacksaw – a fine tooth saw with blade held under tension in a
frame, used for cutting metals or plastics.
Fittings
P-trap – a device designed to seal a liquid or prevent the back
passage of air without affecting the flow of the sewage through
it.
59. Plumbing (Tools and Materials)
Nipple – a short pipe with small opening which provides way for liquid
to pass through the pipe. It has a male thread on each end and is used
for extension from fitting.
Bushing - fittings that can be inserted into one pipe and allow you to
screw another (smaller pipe) pipe into it.
Coupling – a fitting device used to connect two shafts together at their
ends.
Union – like coupling, except it is designed to allow quick and
convenient disconnection of pipes for maintenance. “Union Patente”
Plug – cap end, designed to insert into the end of tube to end the flow
of water.
Cap – similar to plug, it covers the end of a pipe.
Elbows – ¼ bend, 45 degrees and 90 degrees, to change direction
Reducer – used to connect smaller pipe from a larger pipe.
60. Plumbing (Tools and Materials)
Tee
Wye
Valves
Gate valve – it is used to permit or prevent the flow of water.
Check valve – a device which allows liquid to flow through it in
only one direction. It is often used in some types of pumps –
inlet and outlet ball check valves.
Inlet valve – it is used to control the pressure of the flow of
water.
Flush valve – device located at the bottom of the tank for
flushing water closets.
Float valve – used in filling water tanks, avoiding overflow and
backflow of water.
61. Sample Question 1
The Plumbing Law is also known as?
A.) RA7077
B.) RA6442
C.) RA 1387
D.) RA 1378
62. Sample Question 2
If the ideal size of a septic tank for a 6 Family members is
1.3 cu. m, what size will it take to have a family member of
9?
A.) 1.93 cu. m
B.) 1.96 cu. m
C.) 1.92 cu. m
D.) 1.95 cu. m
cu.m/fm = (1.3 cu.m/ 6)
Cu.m/fm=0.216
Septic size = cu.m/fm x N
Septic size = 0.216 x 9
Septic size = 1.95 cu.m
63. Sample Question 3
Plumbing material that is used to connect smaller pipe
from a larger pipe.
A.) Tee
B.) Union
C.) Reducer
D.) Elbow
65. Electricity
Electricity is a form of energy resulting from the
existence of charged particles (such as electrons &
protons). Either statically on an accumulation of
charge of dynamically a current
Current Directional flow of electric charge
66. Electricity (Sources)
Biomass – all solid materials from plants and animals
which energy may be extracted.
Advantages of Biomass Energy
Renewable energy source
Very low greenhouse gas emissions
Can produce energy on-demand
Energy is easily stored
Disadvantages of Biomass Energy
Low energy return on investment
High air pollution emissions
Very high water and land requirements
High occupational hazards
Geothermal Energy – heat energy of the earth.
67. Electricity (Sources)
Hydropower – force of moving water from rivers and water reservoirs.
Advantages of Hydropower
Very high return on energy investment
Very low greenhouse gas & air pollution emissions
Inexpensive once dam is built
Disadvantages of Hydropower
Very high land requirements
Extremely high impacts to land and water habitat
Best sites are already developed or off-limits
Disastrous impacts in case of dam failure
Ocean Power – energy from the currents and waves.
Marine Currents
Two-way currents – caused by ocean tides.
One-way currents – ocean water flowing like rivers.
68. Electricity (Sources)
Solar Energy – heat energy provided by the sun
Advantages of Solar Energy
Renewable energy source
Very low greenhouse gas emissions
Very low air pollution emissions
Very low water requirements
Modular, low-profile, low-maintenance
Very safe for workers and public
Disadvantages of Solar Energy
Intermittent energy source
High land requirements
Expensive
Manufacture involves some toxics
69. Electricity (Sources)
Wind Power – energy from the force of the wind.
Advantages of Wind Power
Renewable energy source
Very low greenhouse gas emissions
Very low air pollution emissions
Very low water requirements
Very safe for workers and public
Disadvantage of Wind Power
Intermittent energy source
Limited to windy areas
Potentially high hazard to birds
Moderate land requirements
70. Electricity (Sources)
Coal Energy – energy derived from burning coals, a rock mostly
made of carbon element.
Advantages of Coal Energy
Inexpensive
Abundant
Low land requirements
Can produce energy on-demand
Disadvantages of Coal Energy
Non-renewable energy source
Very high greenhouse gas emissions
Very high air pollution emissions
High land/water impacts from acid rain, mine drainage
Highly hazardous occupation
71. Electricity (Sources)
Nuclear Energy – energy trapped inside the atom, the same with the
principle of producing energy by heat.
Advantages of Nuclear Energy
Low greenhouse gas emissions
Low air pollution emissions
Low land requirements for power plants (though not for waste storage)
Can produce energy on-demand
Disadvantages of Nuclear Energy
Non-renewable energy source
High water requirements
Relatively expensive
Waste remains dangerous for thousands of years
Serious accident would be disastrous
72. Electricity (Sources)
Natural Gas – energy from methane, a combination of
hydrogen and carbon, formed when organic matters
are trapped beneath the sedimentary layers of the
earth.
73. Electricity (Types of Current)
Alternating Current (AC) - the flow of electrons changes
alternately. It goes positive, and then it goes negative, and
so on as a cycle.
It reverses direction 120 times per second, or 60 cycles per
second – called 60 hertz power.
Direct Current (DC) - the flow of electron in a conductor
is only in one direction.
It flows from negative pole, through a device, and on the
positive pole.
Sources:
Chemical battery , Electronic power supply, and Mechanical
Generator
74. Electricity (Types of Electricity)
Static Electricity – electricity at rest, the buildup of
electric charge on the surface of objects.
Electricity produced by friction
Dynamic Electricity – the flow of electric charge, also
known as electric current. It also known as electricity
in motion.
75. Electricity (Electric Circuit)
Circuit is the complete flow of current through a
conductor or path from the source to the load and back
to the source. It is the continuous flow of current.
Source – it provides electrical power to the circuit. Ex. Cell
or battery, generators.
Load – electrical device (appliances) connected to the
circuit that consumes electricity or power.
Control/Switch – a device that turns the current ON and
OFF.
Path – a conductor composed of 2 or more lines that
provide passage for the current from the source to the load.
76. Electricity (Electric Symbols)
QUANTITY UNIT SYMBOL PROPONENT FORMULA
Electron Current Ampere I or A Andre Ampere I = E / R
Applied Voltage Volt V or E Allesandro Volta V = I x R
Circuit Resistance Ohm R George Ohm R = E / I
Power Watt P James Watt P = I x E
77. Electricity (Types of Circuit)
Series Circuit
Loads are connected end to end along the path of current in a single closed loop.
Current is the same throughout the circuit (Itotal = Il=I2=I3….)
Voltage is equal to the sum of individual voltage drops in a circuit.
(Vtotal = Vl+V2+V3….)
Resistance in series is equal to the sum of individual resistances
(Rtotal = Rl+R2+R3….)
78. Electricity (Types of Circuit)
Series Circuit
(Rtotal = Rl+R2+R3….)
RT=R1+R2+R3
RT=10+10+20
RT=40Ohms
79. Electricity (Types of Circuit)
Parallel Circuit
Loads are connected side by side across the path of the current.
Current in each branch is independent from each other, when branch or load
opens, the other load will still function.
Current is equal to the sum of the individual currents.
(Itotal = Il+I2+I3….)
Voltage drop across each load is the same. (Vtotal = Vl=V2=V3….)
Resistance is found by this formula:
1
-----------------------
1 1 1
--- + --- + ---
R1 R2 R3
80. Electricity (Types of Circuit)
Parallel Circuit
Resistance is found by this formula: (Product over sum)
RT= (R1)(R2)
R1 + R2
RT= (10) (20)
10 + 20
RT= 200
30
RT= 66.66Ohms
81. Electricity (Types of Circuit)
Series and Parallel Circuit
Combination of series and parallel connection in one circuit.
82. Electricity (Ohms Law)
OHM’S LAW
George Simoun Ohm – discovered the
relationships of voltage, current and resistance in a
circuit.
Current is directly proportional to voltage
Increase in voltage will result to increase in current
Current is inversely proportional to resistance
Increase in resistance will result to a decrease in
current
83. Electricity (Basic Computation)
QUANTITY UNIT SYMBOL FORMULA
Electron Current Ampere I or A I = V / R
Applied Voltage Volt V or E V = I x R
Circuit Resistance Ohm R R = V / I
Power Watt P P = I x V
85. Electricity (Ampere “I”)
Ampere is represented as “I”
Voltage is represented as “V”
Resistance is Represented as “R”
How to determine the Ampere required for a voltage of 12V and a resistance of
1o ohms.
I = V / R
I= 12 /10
I=1.2
The Ampere required is 1.2A
86. Electricity (Voltage “V”)
Ampere is represented as “I”
Voltage is represented as “V”
Resistance is Represented as “R”
How to determine the Voltage required for a current of 2A and a resistance of 14
ohms.
V=I x R
V= 2 x 14
V=28
The Voltage required is 28V
87. Electricity (Resistance “R”)
Ampere is represented as “I”
Voltage is represented as “V”
Resistance is Represented as “R”
How to determine the Resistance of the circuit for a current of 2A and a Voltage
of 24V.
R=V/I
R= 24 x 2
R=12
The Resistance is 12Ohms
88. Electricity (Power “P”)
Ampere is represented as “I”
Voltage is represented as “V”
Power is Represented as “P”
How to determine the Power (Watts) for a current of 30A and a Voltage of 220V.
P=V x I
P= 220 x 30
P=6600
The Power or watts is 6600W
89. Electricity (Power “P”)
Ampere is represented as “I”
Voltage is represented as “V”
Power is Represented as “P”
How to determine the Power (Watts) for a current of 30A and a Voltage of 220V.
P=V x I
P= 220 x 30
P=6600
The Power or watts is 6600W
91. Electricity (Circuit Protection)
Breaker – an automatically operated electrical switch designed to protect
electrical circuit caused by overload or short circuit.
(Fuse operates once, must be replaced. Breaker can be reset to resume normal
operation).
20 amp – for convenience outlets (general purpose)
15 amp – for lighting fixtures
30 amp – for heavy duty appliance outlets (SPO) such as ref and aircon.
60 amp - for main breaker
92. Electricity (Circuit Conditions)
Overload – when the total current flowing in the circuit is more than the
capacity of the conductor.
Short Circuit – when insulated conductors from line 1 and line 2 of a circuit
come into contact with each other without passing any load, or when the
resistance of the load becomes unnecessary low.
This is dangerous because it creates a very high flow of current which produces
unusual heat and may cause fire.
Grounded circuit = when one uninsulated conductor touches the metal part of
an appliance. It causes voltage drain, and electrocution when touch by
uninsulated individual.
Open circuit = when the flow of the current is incomplete. When circuit is
switched off.
Closed circuit = when the flow of current is complete. When circuit is switched
on.
93. Electricity (Basic requirements in electrical house wiring)
Prepare a house wiring plan in accordance with the safety standards of the
PEC
PEC – Philippine Electrical Code or NEC – National Electrical Code
Philippine Association of Mechanical and Electrical Engineers (PAMEE)
Determine the load and compute for the expected power and current
consumption.
Identify the service point where electricity will come from
Determine the number of outlets per branch and their specifications
Determine the sizes of the receptacles, tubes and panels
Determine the sizes and ampacity of wires, cables and circuit protectors.
3 watts per square foot – for general purpose circuit (lighting and receptacles)
or 24watts per 1 sq. m for lighting, 100 watts per outlet
A nominal value of 1500 watts for each 20- ampere small appliances and
laundry circuit.
Plus major appliances, (5000 watts for aircon) then get the total load.
94. Electricity (Basic Principles of Good Wiring )
Before beginning any electrical repair, shut off the power.
(Remove the fuse or trip the breaker for the circuit you will be working on in
your service panel)
Prepare and study the wiring diagram. This will help you understand the
basic principles of good wiring.
Electrical wires are color coded to prevent wiring errors.
Black is HOT wire
White is Neutral wire
Green is Ground wire
Red is second HOT wire
Yellow is Traveller wire
95. Electricity (Basic Principles of Good Wiring )
Always use appropriate size of wires
Sizes of wires (As the Number increases the actual size decreases)
Measured in terms of AWG (American Wire Gauge)
# 14 AWG (2.0mm2) – for lighting fixtures
# 12 AWG (3.5mm2) – for convenience outlets
# 10 or 8 AWG (5.5 to 8.5mm2)– for service entrance
96. Electricity (Test Instruments )
Ohm meter – test for resistance
Ammeter – test for current
Voltmeter – test for voltage
Multimeter/ VOM
98. Electronics
Electronics – refers to the flow of charge (moving electrons) through
nonmetal conductors (mainly semiconductors).
The flow of charge through various materials and devices such as,
semiconductors, resistors, inductors, capacitors, and vacuum tubes.
99. Electronics
Electronic components -It refers to any physical entity in an electronic
system whose intention is to affect the electrons in a desired manner consistent
with the intended function of the electronic system
Electronic circuit – composed of different components that are classified as
active and passive components.
Passive – components that do not generate voltage but controls the current in a
circuit.
Ex. Resistors, capacitors, inductors, etc.
Active – components that can generate, amplify and even control voltage and
current in a circuit.
Ex. Diode, transistor, integrated circuits (IC), etc.
100. Electronics
Semiconductors – a group that are neither good conductors nor good
insulators
Inductors – the choke or coil in a circuit that oppose changes in electric
current.
Resistor – a device that opposes the flow of electric current, it lowers the
voltage. It is polarized.
Capacitor - is a passive two-terminal electrical component used to store
energy in an electric field.
Electrical Circuit – a network that has a closed loop, allowing the complete
flow of current.
Conductors – are metals and other substances where electrons can move freely
Insulators – substances where electrons cannot move freely.
Transformer – is an electronic devised used in producing desired voltage.
101. Electronics
Semiconductors – a group that are neither good conductors nor good
insulators
Inductors – the choke or coil in a circuit that oppose changes in electric
current.
Resistor – a device that opposes the flow of electric current, it lowers the
voltage. It is polarized.
Capacitor - is a passive two-terminal electrical component used to store
energy in an electric field.
Electrical Circuit – a network that has a closed loop, allowing the complete
flow of current.
Conductors – are metals and other substances where electrons can move freely
Insulators – substances where electrons cannot move freely.
Transformer – is an electronic devised used in producing desired voltage.
102. Electronics (Tools)
Electric Drill and Drill Bits - in the range of 1/8 inch to 1/2 inch will come in
handy when you need to drill holes.
Soldering Iron - a 20 Watt to 30 Watt soldering iron with tips of 1/8 inch to 1/2
inch can be used for soldering of through hole components.
Disordering Pump - A pump aids in the removal of the liquid solder.
Wire stripper - is used to strip off wire insulator from its conductor before it is
used to connect to another wire.
Long nose Pliers – a 4-inch long nose pliers used to hold components that
have short leads that need to be soldered onto the PCB.
Side-Cutting Pliers - 4-inch side cutting pliers used to trim off excess
component leads on the printed circuit board and to cut wires before being
used.
Small tweezers - is used to hold small components.
Allen Wrench - set is used to unscrew or screw Allen type of screws.
Philips/Flat Head Screwdrivers
Socket wrench - sets that include nut drivers, hex drivers.
103. Electronics (Tools)
Maintenance
Tinning – the process of cleaning and applying a thin coat of solder on the tip
of the pre-heat soldering iron.
Flux – chemical cleaning agent, The purpose of flux is to clean oxides from
metal surfaces to ensure a clean bond in soldering.
Maintenance Tips of Electronic Tools
Ensure that the tools are used only for their intended purposes.
Keep them lubricated with a light film of oil to inhibit rust.
Keep the tools clean and sharp; keep the soldering tips clean and well tinned.
Ensure that proper uses of the tools are always adhered to by following the
instructions of using the tools.
104. Electronics (Components)
Electronic Components
It is a basic electronic element usually packaged in a discrete form, intended to
be connected together, usually by soldering to a printed circuit board, to create
an electronic circuit with a particular function (for example an amplifier, radio
receiver, or oscillator).
105. Electronics (Capacitors)
Capacitor
is a passive electronic component consisting of a pair of conductors separated
by a dielectric.
It stores and discharge electrical energy.
The voltage rating found in a capacitor is called working voltage.
The rating is expressed in capacitance; the unit of measurement in capacitance
is farad.
107. Electronics (Diodes)
It converts AC to DC.
It is a device that conducts current to flow in only one direction.
They are called rectifiers
It is polarized, the terminals are anode (positive) and cathode (negative)
Forward biased – when current is applied to the cathode (negative), it permits
the flow of current. (ON switch)
Reverse biased – when current is applied to the anode (positive), it will not
permit the flow of current. (OFF switch)
Zener diode – used as voltage reference, connected across a circuit where
regulated voltage is required; acts as a regulator
Light emitting diode (LED) – it acts like rectifier diode except that is usually
intended to indicate flow of current.
Photo diode – a diode which is sensitive to light; a light sensitive diode.
108. Electronics (Transistors)
Is an active semiconductor device having 3 electrodes. It could perform a
variety of applications such as switch, amplifier, and rectifier.
The terminals of a transistor are base, collector and emitter.
BASE - which is the lead responsible for activating the transistor.
COLLECTOR - which is the positive lead.
EMITTER - which is the negative lead.
Kinds of Transistor
NPN – arrow pointing outward;
PNP – arrow pointing inward.
The arrow points where negative is; supply is connected to the emitter and
collector.
109. Electronics (Resistors)
Is a device that opposes the flow of electric current, it lowers the voltage.
The simplest components in any circuit. Their job is to restrict the flow of
electrons and reduce the current or voltage flowing by converting electrical
energy into heat.
Variable resistors (also known as potentiometers) have a dial control on them so
they change the amount of resistance when you turn them.
110. Electronics (Resistors)
Color 1st Significant figure 2nd Significant figure Multiplier Tolerance
Black ---- 0 1 ----
Brown 1 1 10 +- 1%
Red 2 2 100 +- 2%
Orange 3 3 1,000 +- 3%
Yellow 4 4 10,000 +- 4%
Green 5 5 100,000
Blue 6 6 1,000,000
Violet 7 7 10,000,000
Gray 8 8 108
White 9 9 109
Gold ---- ---- 0.1 +- 5%
Silver ---- ---- 0.01 +- 10%
No color ---- ---- 20 +- 20%
A resistor is color coded with Yellow-Violet-Black-Gold. What is the
value and tolerance of the resistor?
Yellow = 4; Violet = 7; Black = 1;
47x1 = 47 ohms, +- 5%
111. Let’s Try
Color 1st Significant figure 2nd Significant figure Multiplier Tolerance
Black ---- 0 1 ----
Brown 1 1 10 +- 1%
Red 2 2 100 +- 2%
Orange 3 3 1,000 +- 3%
Yellow 4 4 10,000 +- 4%
Green 5 5 100,000
Blue 6 6 1,000,000
Violet 7 7 10,000,000
Gray 8 8 108
White 9 9 109
Gold ---- ---- 0.1 +- 5%
Silver ---- ---- 0.01 +- 10%
No color ---- ---- 20 +- 20%
2 4 x 10 = 240Ohms +-5%
112. Electronics (Circuit Board)
Breadboard
Temporary, no soldering required
This is a way of making a temporary circuit, for testing purposes or to try out an idea.
No soldering is required and all the components can be re-used afterwards.
It is easy to change connections and replace components
Strip board
Permanent, soldered
Strip board has parallel strips of copper track on one side. The strips are 0.1" (2.54mm)
apart and there are holes every 0.1" (2.54mm).
Strip board requires no special preparation other than cutting to size. It can be cut with a
junior hacksaw, or simply snap it along the lines of holes by putting it over the edge of a
bench or table and pushing hard.
Printed Circuit Board
Permanent, soldered
Printed circuit boards have copper tracks connecting the holes where the components are
placed.
