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CENT-112: Fundamentals of Electricity & Electronics

CENT-112: Fundamentals of Electricity & Electronics

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CENT-112: Fundamentals of Electricity & Electronics

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  1. CENT-112: Fundamentals of Electricity & Electronics Dr. Van de Graaff (MIT Professor) designed and built this generator as a research tool in early atom-smashing and high energy X-ray experiments. This is the standard of excellence we should aspire to. CENT-112 Fundamentals of Electricity and Electronics

  2. Course Outline • Section 1: Fundamentals of Electricity & Electronics • Section 2: Basic Circuits • Section 3: Motors, Generators, & Power Distribution • Section 4: Advanced Electrical Circuits • Section 5: Electronic Communication & Data Systems CENT-112 Fundamentals of Electricity and Electronics

  3. Interest • The great end in life is not knowledge but action. Take your knowledge and use it as soon as you can. • “Use technology as a blessing to mankind and not as a curse.” Einstein 1879-1955 • Improvement ideas: tomsic@hawaii.edu • Website: http://www.hcc.hawaii.edu/~tomsic • 12 labs, 2 projects (audio amplifier & PS) • 3 exams CENT-112 Fundamentals of Electricity and Electronics

  4. Introduce Yourself • Where are you from? • How do you like Honolulu Community College? • What experience do you have in electronics? • What is something interesting about yourself? • What do you want to learn in this class? CENT-112 Fundamentals of Electricity and Electronics

  5. Section 1: Fundamentals of Electricity & Electronics • Safety Precautions • Basic Electrical Terms and Circuits • Basic Measuring Instruments • Basic Electrical Circuit Materials • Energy • Sources of Electricity CENT-112 Fundamentals of Electricity and Electronics

  6. A GOOD THING TO KEEP IN MIND! SAFETY CENT-112 Fundamentals of Electricity and Electronics

  7. THE BEST TOOLS EVER INVENTED … HANDS! CENT-112 Fundamentals of Electricity and Electronics

  8. SAFETY SHIELDS ARE EYE INSURANCE! CENT-112 Fundamentals of Electricity and Electronics

  9. SAFETY SHOES ARE NOT FOR DEFEAT! CENT-112 Fundamentals of Electricity and Electronics

  10. HEARING PROTECTION IS FOR WINNERS! CENT-112 Fundamentals of Electricity and Electronics

  11. Always check Electrical Circuits Deenergized • Discharge capacitors. • Check Power Leads (T1-T3) • Check Capacitors discharged. • < 30VAC is deenergized. CENT-112 Fundamentals of Electricity and Electronics

  12. Electrostatic Discharge (ESD) • Invisible Threat • 1 touch can ruin this card. • Wear a wrist strap. CENT-112 Fundamentals of Electricity and Electronics

  13. General Safety Rules • Do not work when you are tired or taking medicine that makes you drowsy. • Do not work in poor light. • Do not work in damp areas or with wet or damp clothing and shoes. • Use approved tools, equipment, & protective devices. • Remove all metal items when working around exposed circuits. CENT-112 Fundamentals of Electricity and Electronics

  14. General Safety Rules Continued • Never assume that a circuit is off. Double-check it with an instrument that you are sure is operational. • Buddy system is used at circuit breaker supplying power if working on circuit. • Never override safety interlocks. • Keep all tools and test equipment in good working condition. • Discharge capacitors. CENT-112 Fundamentals of Electricity and Electronics

  15. General Safety Rules Continued • Do not remove grounds and do not use adapters that defeat the equipment ground. • Use CO2 or halogenated-type fire extinguisher to put out electrical fires. Water conducts electricity! (i.e. galley fire in oven). • Store solvents and other chemicals in appropriate areas. (i.e. fire personnel incident). • Do not work on unfamiliar circuits. • Do not cut corners or rush. No horseplay or practical jokes in the labs (i.e. throwing caps, meggering). CENT-112 Fundamentals of Electricity and Electronics

  16. Shock Victim • Do not become part of the problem. • Use non-conductive belt and break free shock victim. • Call for medical assistance. (911) CENT-112 Fundamentals of Electricity and Electronics

  17. Review CPR • Check for response. • Have someone call 911. • Clear airway. • Look, listen and feel for breathing. • Give 2 full breaths. • 15 compressions (1 and 2 and 3) • Continue till medical help arrives, you are relieved or are too tired to continue. CENT-112 Fundamentals of Electricity and Electronics

  18. Questions • Q1. Who is responsible for safety? • A1. Everybody is responsible for their safety. • Q2. What protects electronic circuits from ESD? • A2. ESD packaging & wrist straps. • Q3. What is the worst electrical shock you have heard of or experienced? • A3. Various. CENT-112 Fundamentals of Electricity and Electronics

  19. Scientific Notation CENT-112 Fundamentals of Electricity and Electronics

  20. Ohms Law Given: E = Voltage I = Current R = Resistance E I R E=IR I = E/R R = E/I CENT-112 Fundamentals of Electricity and Electronics

  21. Basic Electrical Terms • Definitions • Current (I): Flow of electrons past a point. 1A = 1 coulomb of charge flowing past a point for 1 second. Unit of measure is amps. • Resistance (R): Opposition to the flow of electrons. Unit of measure is ohms. • Voltage: (E): Force behind electrical flow. Unit of measure is the volt. CENT-112 Fundamentals of Electricity and Electronics

  22. Questions • Q4. Given a 1 Megohm resistor with a 120 volt potential applied to it, what current will pass through it? • A4. .12 milliamps • Q5. Can this current kill you if you touch it? • A5. No. .1 Amp for 1 second can be fatal. • Q6. How many students know CPR? • A6. It is a good thing to be qualified in CPR when working on or near electrical circuits. CENT-112 Fundamentals of Electricity and Electronics

  23. Questions Continued • Q7. Given a 1.5 Amp battery charger with a total circuit resistance of 8 ohms, what supply voltage is generated? • A7. 12 volts • Q8. What amperage is present when you place the new chip in your cellular phone? • A8. micro amps. • Q9. What amperage is present when you put leads on a new car battery? • A9. milliamps CENT-112 Fundamentals of Electricity and Electronics

  24. Definitions • Atomic Theory • Foundation for Solid State Devices • Atom - Smallest part of an element that retains the characteristics of that element. • Molecule – Smallest part of a compound. • Compound - 2 or more elements chemically combined. CENT-112 Fundamentals of Electricity and Electronics

  25. Atom Parts: • Electrons: Negative part of an atom. • Protons: Positive part of an atom. • Neutrons: Negative part of an atom. The Atom E E E E E P N N P E E E E E CENT-112 Fundamentals of Electricity and Electronics

  26. Static Electricity • Like charges repel each other and unlike charges attract each other. • Walking across a wool or nylon rug , you can generate a static charge of electricity, discharging several thousand volts of electricity to a metallic object like a door handle. CENT-112 Fundamentals of Electricity and Electronics

  27. Definitions • Coulomb: Practical unit of measurement of the amount of electricity. Used to describe the flow of electricity. • 1 Coulomb = 6.24 X 1018 electrons. • Electrostatic or Dielectric field: The field or force surrounding a charged body. • Charge Transfer • Direct Contact • Induction: Electron flow due to charged object in close proximity. CENT-112 Fundamentals of Electricity and Electronics

  28. Valence Electrons are those electrons which are located in the outermost or “Valence” shell of an atom. • The number of valence electrons an atoms has determines the electrical properties of that atom. • < 4 electrons => Conductor • > 4 electrons => Insulator • 4 electrons => Semiconductor Energy Band Diagrams CENT-112 Fundamentals of Electricity and Electronics

  29. Energy Band Diagrams Continued Conductor Semiconductor Insulator Valence Band Forbidden Band Conduction Band CENT-112 Fundamentals of Electricity and Electronics

  30. Bonding • Covalent vs. IonicBonding • “Octet” Rule and Covalent Bonding • “N” and “P” Crystals • Base Material - Silicon or Germanium • Doping - Process by which impurity atoms are added into a pure base material to create a compound with improved electrical properties. This process is used when making semiconductors. CENT-112 Fundamentals of Electricity and Electronics

  31. Static Device Application • Electrostatic Precipitator: Collector Plates need cleaning. Ionizer Plate: Positively charges Particles in air Collector Plate: Negative plates collects + ions. Mechanical Filter Oil Mist Clean Air CENT-112 Fundamentals of Electricity and Electronics

  32. Basic Electrical Circuit Power Supply(Source) Load(Light) Conductor CENT-112 Fundamentals of Electricity and Electronics

  33. + + 0 0 - - Types of Current • AC: Alternating Current • DC: Direct Current CENT-112 Fundamentals of Electricity and Electronics

  34. Circuit Flow • Conventional Current Flow: Hole flow. • Electron Flow • Series Circuit • Parallel Circuit • Series/parallel Circuit CENT-112 Fundamentals of Electricity and Electronics

  35. Basic Instruments & Measurements Simpson 260 Fluke 177 CENT-112 Fundamentals of Electricity and Electronics

  36. Interest • One of the first meter instruments was used by the Greeks (0 BC) and was the Sun Dial. CENT-112 Fundamentals of Electricity and Electronics

  37. Outline • Types of meter movement • Types of meters • Voltmeter • Ammeter • Ohmmeter • Electrical diagrams CENT-112 Fundamentals of Electricity and Electronics

  38. Basic Multimeters • A meter is a measuring instrument. • Ammeter: measures current. • Voltmeter: measures the potential difference (voltage) between two points. • Ohmmeter measures resistance. • Multimeter: combines these functions and others into a single instrument. CENT-112 Fundamentals of Electricity and Electronics

  39. Ammeter • Measures current in amperes, milliamperes, microamperes depending on the meter scale. • The coil in the meter movement is wound with many turns of fine wire. • If a large current was allowed to flow the coil, it would burn it out, so a shunt or alternate path is provided for current. Most of the current flows through the shunt. • Safety: Connect an ammeter is series with a circuit device. Never in parallel! CENT-112 Fundamentals of Electricity and Electronics

  40. Determining Shunt Resistors • Meter movement requires 1mA for full scale deflection. The resistance of the coil is 100Ω. The ranges of the meter are: 0-1mA, 0-10mA, 0-50mA, 0-100mA. • E=IR = (.001)(100) = .1V without a shunt. For full scale deflection, .1V is required. • A shunt must carry 90% of the current for the 0-10mA scale. • Rs =E/I = .1/.009 = 11.1Ω • Calculate the other shunt resistors. CENT-112 Fundamentals of Electricity and Electronics

  41. Voltmeter • To ensure voltages across the coil never exceed .1V, multiplier resistors are placed in series with the meter movement coil using a switch. • Voltage ranges 0-1V, 0-10V, 0-100V, 0-500V • .1V can be placed across meter at any one time, therefore a resistor must drop .9V to use a 0-1V scale. Full scale current deflection is 1mA or .001A • Rm = E/I + .9V/.001A = 900Ω • Calculate multiplier resistors for other scales. CENT-112 Fundamentals of Electricity and Electronics

  42. Ohmmeter • Uses non-linier scale: zero-infinite. • Calibrate prior to use for analog meter. • Check leads at 0Ω for good lead connections. • Electrical leads safety story for finger stop. CENT-112 Fundamentals of Electricity and Electronics

  43. Moving Iron Vane Meter CENT-112 Fundamentals of Electricity and Electronics

  44. Moving Iron Vane Meter • Measure either AC or DC. • It depends on induced magnetism for its operation. It utilizes the principle of repulsion between two concentric iron vanes, one fixed and one movable, placed inside a solenoid. A pointer is attached to the movable vane. When current flows through the coil, the two iron vanes become magnetized with north poles at their upper ends and south poles at their lower ends for one direction of current through the coil. Because like poles repel, the unbalanced component of force, tangent to the movable element, causes it to turn against the force exerted by the springs. CENT-112 Fundamentals of Electricity and Electronics

  45. D'ARSONVAL METER MOVEMENT • The permanent-magnet moving-coil movement used in most meters . CENT-112 Fundamentals of Electricity and Electronics

  46. D'ARSONVAL METER MOVEMENT • D'Arsonval meter movement is capable of indicating current in only one direction. • Without a rectifier, or direct current of the wrong polarity, the meter would be severely damaged. • Since the pointer will vibrate (oscillate) around the average value indication, damping is used. • Airtight chamber containing a vane • The movement of the coil (conductor) through a magnetic field causes a current to be induced in the coil opposite to the current that caused the movement of the coil. CENT-112 Fundamentals of Electricity and Electronics

  47. Digital Multimeters (DMM) • DMM are smaller and more accurate in measurement. • Analog meters can measure transients information better. • Measures resistance, DC & AC voltage, amperage, and diode testing. CENT-112 Fundamentals of Electricity and Electronics

  48. Questions • Q. What is the difference between diode testing and resistance checking? • A. The diode check is more sensitive with an audible sound for continuity. • Q. What are some experiences that you have with different meters? • A. Various CENT-112 Fundamentals of Electricity and Electronics

  49. RC RB Q1 Electrical Diagrams • One line Diagram • i.e. Motor Controllers • Wiring Diagram • i. e. Ceiling Fan • Block Diagram • i. e. Car Stereo • Schematic Diagram • i. e. VCR player L1 L2 M Not Connected Connected Antenna Speaker RF AMP Detector AF AMP CENT-112 Fundamentals of Electricity and Electronics

  50. Schematic Diagram Logic Output Amplifier Using a UJT and a SCR INPUT FROM LOGIC +15 VDC LOGIC SUPPLY 10K 1K LOAD 115 VAC CENT-112 Fundamentals of Electricity and Electronics