ECT – Electronics 1 Prepared by Ms Nur Aishah Bt Azriy B. Eng (Hons) in Mechatronics Engineering (Automotive) Learning Outcome • This course covers fundamentals of analogue electronics which comprises of topics such as: the concept of semiconductors and electronic devices and its application, together with hands on practical. • The course learning outcome divided in three cores: CLO 1 Describe the concepts of semiconductor and characteristics curve the various types of diodes and transistors CLO 2 Explain the operation of semiconductor devices and circuit operation the various types of diodes and transistors. CLO 3 Evaluate the current, voltage and power in circuits of diodes and transistors Assessment Methods Distribution Percentage CLO 1 CLO 2 CLO 3 Class Test 1 10 % × Class Test 2 10 % × × × Assignment 10 % × × Tutorials 30 % × × × Final Exam 40 % × × × Total 100 % × × × List of Courses Title Sub Title Introduction Basic definitions, types of elements, Ohm's Law, types of components AC Circuit Theory of Semiconductors Theory of Diode Diode Circuits : Basic definitions of AC circuit, Introductions of Oscilloscope, Capacitors, Inductors, Conductors, semiconductors, silicon crystals, intrinsic semiconductors, doping a semiconductor, two types of extrinsic semiconductors, The Operation of diodes. Unbiased diode, forward bias, reverse bias, breakdown, energy levels, reverse biased diode Basic ideas, ideal diode, diode approximations, diode I-V characteristic curve, reading diode datasheet, DC resistance of a diode, load lines. Basic diode circuit. Half-wave rectifier, full-wave rectifier, bridge rectifier, capacitor-input filter. To acquire hands-on laboratory experience, utilizing oscilloscopes and other modern test equipment. Peak inverse voltage, clippers and limiters, clampers. To acquire hands-on laboratory experience, utilizing oscilloscopes and other modern test equipment. Assessment Schedule WEEK NO. Class Test 1 Class Test 2 Assignment Tutorials Final Exam 1 2 3 4 5 6 7 8 9 Chapter 1 - Introduction Learning the basic of electronics element INTRODUCTION • Knowing about quantities and electric unit is important to understand the process of circuit’s operation. • Quantities is something that can be measured and unit is based on name of that certain quantities. • In this electrical and electronics subjects, it is important to understand the basic quantities SI unit for charge (Q), current (I), voltage (V), resistor (R), power (P), and energy (W). System of Units • As engineers, we deal with measurable quantities. • Such an international measurement language is the International System of Units (SI). • In this system, there are six principal units from which the units of all other physical quantities can be derived. Quantity Length Mass Time Electric Current Temperature Luminous intensity Basic Unit Meter kilogram second ampere Kelvin candela Symbol M kg s A K Cd System of Units ο Knowing your units is important! ο Kilo and Mega are common inresistors ο Milli, micro, nano and pico can be used in other components Multiplier 1012 109 106 103 10-3 10-6 10-9 10-12 Prefix Tera giga mega kilo milli micro nano pico Symbol T G M K m µ n p BASIC CONCEPTS AND DEFINITIONS 1. CHARGE • The most basic quantity in an electric circuit is the electric charge. • We all experience the effect of electric charge when we try to remove our wool sweater and have it stick to our body or walk across a carpet and receive a shock. • Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C). • Charge, positive or negative, is denoted by the letter q or Q. BASIC CONCEPTS AND DEFINITIONS 1. CHARGE • We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. • We also know that the charge ‘e’ on an electron is negative and equal in magnitude to 1.602x10−19 C, while a proton carries a positive charge of the same magnitude as the electron and the neutron has no charge. • The presence of equal numbers of protons and electrons leaves an atom neutrally charged. BASIC CONCEPTS AND DEFINITIONS 2. CURRENT • Current can be defined as the motion of charge through a conducting material, measured in Ampere (A). • Electric current, is denoted by the letter i or I. • Mathematically, πΆβππππ π πΌ= = ππππ π‘ BASIC CONCEPTS AND DEFINITIONS 2. CURRENT • Two types of currents: 1) A direct current (DC) is a current that remains constant with time. 2) An alternating current (AC) is a current that varies with time. Fig 1. 2 Two common types of current: (a) direct current (DC), (b) alternative current (AC) EXAMPLE 1 • Determine the current in a circuit if a charge of 80 coulombs passes a given point in 20 seconds (s). Solution: π 80 πΌ= = =4π΄ π‘ 20 EXAMPLE 2 How much charge is represented by 4,600 electrons? Solution: Each electron has - 1.602x10-19 C. Hence 4,600 electrons will have: -1.602x10-19x4600 = -7.369x10-16 C BASIC CONCEPTS AND DEFINITIONS 3. VOLTAGE • By definition: One volt is the potential difference (voltage) between two points when one joule of energy is used to move one coulomb of charge from one point to the other. • The unit of voltage is the volt (V). BASIC CONCEPTS AND DEFINITIONS 3. VOLTAGE • A battery is a type of voltage source that converts chemical energy into electrical energy. • Solar Cells convert light energy into electrical energy. • Generators convert mechanical energy into electrical energy. • Electronic power supplies (voltage converters)? • They do not produce electrical energy, but they transform the ac voltage from the wall outlet into a constant de voltage for use in our circuits. BASIC CONCEPTS AND DEFINITIONS 4. RESISTANCE • The property of a material that restricts the flow of electrons is called resistance. • The unit of Resistance is Ohm (β¦). • By definition: One ohm of resistance exists if there is one ampere of current in a material when one volt is applied across the material. BASIC CONCEPTS AND DEFINITIONS 4. ENERGY AND POWER • Energy is the ability to do work - joules (J) • Power is the rate at which energy is used - in watts (W) • By definition: One watt is the amount of power when one joule of energy used in one second. π πΈπππππ¦, π πΈπππππ¦, π πππ€ππ = πΌπ = = = π‘ πΆβππππ, π ππππ, π‘ EXAMPLE 3 An electric heater consumes 1.8Mj when connected to a 250 V supply for 30 minutes. Find the power rating of the heater and the current taken from the supply. Solution: P = W/t = (1.8×10^6)/ (30×60) = 1000 W Power rating of heater = 1kW P=VI Thus I=P/V=1000/250=4A Hence the current taken from the supply is 4A. Ohm’s Law • Ohm’s law describes mathematically how voltage, current, and resistance are related. • Hence, current and voltage are linearly proportional. • In resistive circuits, with a constant resistance, if voltage increases or decreases by a certain percentage, so will current. • On the other hand, current and resistance are inversely related. • With constant voltage, if resistance is reduced, current goes up; when resistance is increased, current goes down Resistors ο A resistor impedes the flow of electricity through a circuit. ο Resistors have a setvalue. ο Since voltage, current and resistance are related through Ohm’s law, resistors are a good way to control voltage and current in your circuit. More on resistors ο Resistor colorcodes 1st band = 2nd band = 3rd band = 4th band = 1st number 2nd number # of zeros / multiplier tolerance Color code ο Tolerance: Gold = within 5% Capacitors ο A capacitor stores electricalenergy. ο This pool of electrons is available for electronic components to use. Capacitance is measured in Farads. The small capacitors usually used in electronics are often measured in microfarads and nanofarads. Some capacitors are polarized. Notethe different length terminals on one of the capacitors. Polarity of capacitors ο The shorter terminalgoes on the negativeside. ο The stripe is on the negative terminal sideof the capacitor. ο The board is marked for positive or negative. Applications of capacitors ο Capacitors supply a pool of electrons for immediate use. ο If a component needs an immediate supply of electrons, the capacitor can supply thoseelectrons. ο Capacitors can smooth out a signal – eliminate the ripples or spikes in DCvoltage. ο The capacitor can absorb the peaks and fill in the valleys of a rippledsignal. Diode ο A diode is a one way valve (or gate) for electricity. It is a component with an asymmetrical transfer characteristic. A diode has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other direction. ο Diodes will protect yourelectronics. Diode circuit protection ο In a DPDT switch, if polarity is wrong, the motor will run backwards. ο In an electronic circuit, if the polarity is wrong, you can fry your components. A diode in your system will help to prevent problems. Diodes have a bar on the cathode (negative) side. Light emitting diode (LED) ο A light emitting diode (LED) is a semiconductor light source. When electricity is passing through the diode, it emits light. ο Jeremy is going to talk a lot more about LEDs. Variable resistor / Potentiometer ο A potentiometer is a variable resistor. As you manually turn a dial, the resistance changes. How a variable resistor works ο As the dial/wiper turns, electricity must go through more or less of the resistive strip. In series, the change in resistance means a change in voltage. ο So as you turn the dial/wiper, you get a change involtage. Transistors ο A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. ο This is our electronicswitch! How a transistor works ο A voltage or current applied to one pair of the transistor’s terminals changes the current through another pair of terminals. ο A transistor is composed of semiconductor material with at least threeterminals for connection to an external circuit. Transistors have 3 pins. For these transistors: Collector Emitter Base Terminology ο BJT versus FET ο Bipolar junction transistor. Useful asamplifiers. Collector, Emitter, Base ο Field-effect transistor. Useful as motordrivers. Source, Drain, Gate MOSFET: Metal-oxide-semiconductorFET ο NPN (N-channel FET) versus PNP (P-channel FET) ο NPN versus PNP is how the semiconductors are layered. NPN: Not pointing in PNP: Pointing in permanently Schematic symbols BJT PNP P-channel FET BJT NPN N-channel FET Integrated circuit ο An integrated circuit (IC) is a set of transistors that is the controller or ‘brain’ of an electronic circuit. ο An input is received, an output is sent out. Modern microprocessor ICs can have billions of transistors per squareinch! What an IC can do for us? ο Billions of electronically controlled on/offswitches (transistors) is how the microprocessor in a digital computer ‘thinks’ and functions. ο A computer has a wide range of tasks to perform. οBut other ICs can complete simpler, discrete jobs. For example, an IC can take a voltage input and output commands to a motor. IC Terminology: Op-amp ο An operational amplifier (op-amp) is a set of transistors inside the integrated circuit. They often are the components doing the mathematicaloperations. Printed Circuit Board ο Components are attached to a printed circuit board. ο The ‘front’ side of the board will have printed component information, such as resistor # and resistance, diode type and polarity, etc. ο Holes go all the way through the board from one side to the other. Throughhole soldering is needed to connect components to the board. Back of Circuit Board ο The ‘back’ sideof the board will have lines indicating connections between components. The lines on the back are similar towires. ο Thicker lines denote more current (electrons)moving through. ο Components connect the lines. End of Chapter 1 Got any questions?
