Drafting

DraftingDrafting EquipmentDrawing Pencil is made up of a much better grade of graphite commonly called lead, then the ordinary writing pencils so it is possible to draw lines which are of uniform blackness and to do better quality of line work.The hardest of the drawing pencils is the 9H. The next hardest in order are the 8H, 7H, 6H, 5H, 4H, 3H, 2H, H, HB, B, 2B, 3B, 4B, 5B, and 6B. The 6B is the softest of all the drawing pencils.

Cross-Ruled Paper paper which has uniform spaced lines running both vertically and horizontally. The lines are commonly spaced at 1/8 inch or inch apart. The paper is used primarily drawings of objects, either freehand or mechanically.Rule is necessary in order to make sketches of objects, necessary to make the measurements from the part. Erasers when errors happens when making a drawing like a line is drawn too long or in wrong place, the correction is done by using an eraser.

Drawing board smooth surface drawing boards are usually made of soft wood such as basswood or pine in which thumbtacks can readily used. Drawing boards come in various sizes such as 12 x 17, 16 x 21 and 20 x 24 .T Square used to draw all horizontal lines. It is also used for a guide in drawing inclined and vertical lines with the triangles. It is composed of two parts, the head and the blade.Triangle used for drawing vertical and oblique lines.

Common types of triangles- 30 x 60 degrees triangle- 45 x 90 degrees triangle

Other ToolsProtractor used for measuring and laying out arcs of circles as well as angles that cannot be measured by either of the triangles.Triangular scale used to reproduce the dimensions of an object full size/reduced or enlarged to some regular proportion

French Curve a curve ruler (called irregular curve) used to draw curves except circles and arcs.Divider used for dividing lines into any number of equal parts and transferring measurements and spacing points or lines.Compass use for drawing arcs and circles Geometric FiguresGeometric figures are commonly use in drawing are lines, angles, quadrilaterals, regular polygon, circles and arcs and solids.Line is a set of points. A portion of the line between two distinct points is called a line segment.Straight Line is the shortest distance between two points.Parallel lines are lines on the same plane which will not meet no matter how long you extend them

Perpendicular lines are two lines which for right angles.Angle is a figure formed by two rays with common end point.Straight Angle angle whose measure is 180 degrees.Right Angle angle whose measure is 90 degreesAcute Angle angle whose measure is less than 90 degrees.Obtuse Angle angle whose measure is more than 90 degrees but less than 180 degrees.

Complimentary Angles two angles whose sum measures 90 degrees.Supplementary Angles two angles whose sum measure 180 degrees.Polygon is a closed figure formed by line segments intersecting at end points. The line segments are called sides of the polygon.Classification of PolygonTriangle is a three-sided polygonEquilateral Triangle has three sides equalIsosceles Triangle has two sides equalScalene Triangle has one of the angles that is a right angle.Quadrilateral is a four-sided polygonParallelogram is a quadrilateral with right angleRectangle a parallelogram with right angleSquare a rectangle with four equal sidesRhombus a parallelogram whose adjacent sides are unequal and whose angles are not right anglesTrapezoid a quadrilateral with one pair of opposite sides parallel in which one of them is longer than the other.Isosceles Trapezoid- is a trapezoid with its non-parallel sides equalTrapezium a quadrilateral with no parallel sides and no equal angles. RectangleSquareRhombusTrapezoidTrapeziumIsosceles TriangleRight TriangleEquilateral TranglePentagon- a five-sided polygon (108 degrees)Hexagon- polygon with six sides (120degrees)Heptagon polygon with seven sides(128.56 degrees)Octagon polygon with eight sides (135degrees)Nonagon polygon with nine sides(140degrees)Decagon polygon with ten sides(144 degrees)

Circle - is a closed curve, all points are equidistant from the center. An arc is a portion of the circumference of a circle.Terms related to a circle or part of a circleConcentric circle consist of two or more circle having a common center.Eccentric circle are circles having no common centerEllipse an oblique circle with two axes, the minor and the major axes.Radius a line segment from the center to any point on the circleChord a line segment whose endpoints lie on the circle

Pictorial DrawingThe word pictorial comes from the word picture: therefore, a pictorial drawing resembles as a picture. Under general heading of pictorial drawings are isometric, oblique, and perspective drawings.Isometric Drawing all the principal edges of the object except the vertical edge are drawn at 30 degrees to the horizontal. The bottom and top edges which would normally be horizontal, are drawn 30 degrees with the horizontal.Oblique Drawing differs from the isometric that only two faces are drawn at angle. The receding faces-top and right and left sides maybe drawn at any angle. Most commonly used 45 degrees.Perspective Drawing This used more by artists and architects than by engineers. It more nearly resembles the way objects actually appear to the observer than does either isometric or oblique. Orthographic Projection The working provides the mechanic with the information about the size and shape which is necessary for the construction of the object. It may contain three or more views.

Graphs, Chart and MapsGraphs and Charts are widely used to show in an objective manner the relationship of different numbers, sizes of objects, speeds and surface areas.The ability to read charts intelligently and to make simple graphs and charts to illustrate your ideas is an important part of general education. Graphs and charts provide an effective method of portraying ideas quickly and interestingly.Line graphs, bar graphs, area graphs, volume graphs, pictorial graphs and organizational charts are common devices for portraying ideas graphically.Line Graph usually constructed by placing two sets of figures in relation to each other on axes formed by two lines perpendicular to each other which intersect at a point.Bar graph are excellent for comparing quantities, values, and percentages. The height of each bar represents different percentage or quantity.Area graph combine the features of Line and Stacked Bar Graph by coloring the areas underneath each line.Volume graph suitable when only two or three items are to be compared.Pictorial graph pictorial comparison can be made effectively by using geometric or pictorial symbols. Pictorial graphs often give the impression of the third dimension and are useful in comparing volumes.Pie Chart useful in making percentage comparison. It is easily used, easily to make and easy to read. Basic Electricity and ElectronicsElectricityElectricity comes from the Greek word elektron and also in the New Latin word of electricus, meaning amber. Electricity is widely used form of energy that encompasses a variety of phenomena resulting from presence and flow of electric charge. The electric charge is the flow or movement of lost electrons from an atom.Hence Electricity is the movement or flow of electrons in a conductor.Conductors and InsulatorsGenerally, METALS are good conductors of electricity, where electrons easily move from one atom to another, in other words, CONDUCTORS are materials with very low resistance, and thus it easily permits the flow of current. NON-METALS are usually non-conductors of electricity and are used as insulators. INSULATORS are materials with very high resistance, hence, it does not easily permit the flow of electric current.Kinds of ElectricityStatic Electricity it is electricity that is not in motion or electricity at rest. It is usually generated by means of friction. Example: LightningDynamic or Current Electricity it is electricity in motion. It can be transmitted through a conductor from one place to another by means of potential difference.Sources of ElectricityMechanically generated electricity(Motors and Dynamo)Rotary magnetic machineWater-powered machine(hydroelectric power)Geothermal powerGenerator engines oil-driven, gas-driven,diesel-driven,steam-driver2. Chemically generated electricityElectric cells or Battery

Sources of Electrical PowerAC (Alternating Current) Source - common household convenience outlet where appliances are plugged or an electrical transformerDC (Direct Current) Source Cells, Batteries, power adaptors

Properties of ElectricityCurrent is the intensity of the flow of electrons in a conductorVoltage is the electromotive force (EMF) that enables or pushes the electrons to flow in a conductor toward a certain direction.Resistance It is the force that opposes the flow of electrons.Power it is the total measure of electrical energy consumed in a circuit.Electrical Symbols

Parts of a Simple Electrical CircuitA complete circuit consists of a device or board, a path for the current flow, a method of control and a source of electrical energy.

L1L2AC SourceBulbPathSwitchLoad are electrical device like lighting fixture and appliances that consumes electrical energy.Path are wire use as conductor of electricity which provides passage for electric current from the source and back.Control is an electrical device that control or turns the circuit on and off conveniently.Source are electrical energy coming from either alternating current or direct current that provides electrical power to the circuit.Types of Electrical CircuitSeries Circuit this type of circuit in which all load are connected in a straight line, like a chain. If one load is open (defective), other load will not function as well.Parallel Circuit in voltage, the voltage drop across each load is the same. When load is open (defective), the other will not be affected.ElectronicsIs the branch of science and engineering concerned with the theory, design, and the use of devices which involves the transmission of power by utilizing electron emission or absorption. Electronics includes all aspects of photoelectric cells, transistors, circuits, cathode-ray tubes, electron tubes, oscilloscope, electron microscope, broadcasting, radio, television, telephony and many other industries.Definition of TermsElectronic components is any physical entity in an electronic system whose intention is to affect the electrons or their associated fields in a desired manner consistent with the intended functions of the electronic system.Electrical Circuit is a network that has closed loop, giving a return path for the currentNetwork- is a connection of two or more components, and may not necessarily be a circuit4. Conductors are metals and other substances where electrons can move freely.5. Insulators- substances where electrons cannot move freely.6. Transformer is an electronic device used in producing desired voltage.7. Inductors the choke of coil in a circuit that oppose changes in electric current.8. Semiconductors a group that neither good conductors nor good insulators.Basic Electronic ToolsElectric Drill and Drill Bits in the range of 1/8 inch to inch will come in handy when you need to drill holes on the printed circuit board that has been etched. Soldering Iron a 20w to 30w soldering iron with tips of 1/8 in to inch can be used for soldering of through hole components.Disoldering Pump a pump aids in the removal of the liquid solder. It is operated by a spring-loaded vacuum pump and controlled by a simple trigger.Wire stripper used to strip off wire insulator from its conductor.Long nose pliers a 4 inch long nose pliers will come in handy when you need to hold components that have short leads that need to be soldered onto PCB but will be too hot to handle with bare hands.Side cutting pliers use when trimming off excess components leads on the PCB. It can be used also to cut wire into shorter length.Allen Wrench set set is sometimes used to unscrew or screw Allen type of screw.Philips Head Screwdrivers- will be handy as a lot of electronics projects that use screws are Philips Head type.Flat Head Screwdrivers necessary as many projects used are of this type.Pocket Knife will be useful when one need to cut PCB, wires or remove some copper from the printed circuit board.Electronic ComponentsCapacitors is a device that able to temporarily store electricity.Types of CapacitorElectrolytic Capacitor Tantalum CapacitorCeramic CapacitorPolystyrene Film CapacitorMica CapacitorMetalized Polyester Capacitor

Variable CapacitorTrimmer Capacitor

2. Diode device used to limit the movement of electricity to move in one specific direction. Some diodes are also designed to produce light or to act as a switch in an electrical circuit.Type of DiodeLight Emitting DiodeAvalanche DiodeLaser DiodeSchottky DiodeZener DiodePhotoDiodeVaricap Diode or Varactor Diode Retifier Diode3. Transistor An electrical circuit needs to have switches to control the current. In electronic equipment, the most useful kind of switch is the transistor.4. Resistor is an electronic component that resist the flow of current or flow of charge in a circuit. Resistors come in many different shapes and size. Variable resistors (potentiometer) have a dial control on them so they change the amount or resistance when you turn them.

Types of ResistorsVariable Resistor(Potentiometer)Variable Resistor Carbon Composition ResistorFilm or Cement ResistorWire-wound ResistorMetal Oxide Film resistorVitreous Enamel ResistorCement ResistorSemiconductor ResistorResistor Color Coding

Types of Circuit BoardBread Board Temporary, no soldering requiredThis is a way of making a temporary circuit, for testing purposes or to try out an idea.2. Strip BoardPermanent, solderedStrip board has parallel strips of copper track on one side3. Printed Circuit BoardPermanent, solderedPCB have copper track connecting the holes where the components are placed.Electronic Symbols

Table of resistor symbolsLogic Gates

Resistor (IEEE)Resistor reduces the current flow.

Resistor (IEC)

Potentiometer (IEEE)Adjustable resistor - has 3 terminals.

Potentiometer (IEC)

Variable Resistor / Rheostat (IEEE)Adjustable resistor - has 2 terminals.

Variable Resistor / Rheostat (IEC)

Trimmer ResistorPreset resistor

ThermistorThermal resistor - change resistance when temperature changes

Photoresistor / Light dependent resistor (LDR)Photo-resistor - change resistance with light intensity change