EEE118. Electronic Devices and Circuits Part 1 EEE118: Electronic - PDF document

EEE118: Lecture 1 Introduction EEE118. “Electronic Devices and Circuits” Part 1 EEE118: Electronic Devices and Circuits Lecture I Lectures 1 & 2. Passive Components and Circuit Theorems Lecture 3. Diodes I James E. Green Lecture 4. Conduction State Problems in Diodes Department of Electronic Engineering University of Sheffield j.e.green@sheffield.ac.uk Lecture 5. Pulse Circuits Containing Diodes. Lectures 6 & 7. Five Common Diode Circuits Lectures 8 & 9. Rectification and Stabilisation 2/ 28 1/ 28 EEE118: Lecture 1 EEE118: Lecture 1 Introduction Introduction Aims & Objectives Aims & Objectives 1 This Lecture 1 Introduction Aims & Objectives To begin our description of the operation, analysis and 2 Books design of electronic components and circuits. 3 Problem Sheet These circuits are formed from, 4 Circuits Terminology Active elements 5 Units Diodes Transistors (e.g. BJT, JFET & MOSFET) 6 Passive Components Integrated Circuits (ICs) Resistors Passive elements Resistor Colour Codes Capacitors Resistors Capacitors 7 Review Inductors 8 Bear 1 See http://eee.dept.shef.ac.uk/admissions/modules/eee118.pdf 3/ 28 4/ 28 EEE118: Lecture 1 EEE118: Lecture 1 Introduction Introduction Aims & Objectives Aims & Objectives How is this different from the other stuff? What to expect... Slides & Notes In Prof. Heffernan’s part of the course the objective is The Handout Pack (Don’t leave without one...) Older Handouts & past exams + solutions available on-line to understand how electronic devices work http://hercules.shef.ac.uk/eee/teach/resources/eee118/eee118.html What happens inside devices? Where do the electrons and holes Videos of the lectures available on-line 2 go? Why? Homework In this part of the course the objective is Problem sheets & problem classes (solutions online) to understand how to make electronic devices work Information Commons and Diamond Library Can I use what I know about electron device operation and circuit Need Help? Email Me! design to build an (amplifier/oscillator/mixer/VCA etc.)? 2 no not those videos, proper videos done properly with a camera. 5/ 28 6/ 28

EEE118: Lecture 1 EEE118: Lecture 1 Books Problem Sheet Books Background Skills Problem Sheet It should be possible to fully attempt the background skills problem sheet now. Horowitz, P. and Hill, W., “The Art of Electronics”, Cambridge University Press, 3rd ed., 2015. Sedra, A. S., and Smith, K. C., “Microelectronics”, Oxford University Press, 5th ed., 2006. Millman, J., and Grabel, A., “Microelectronics”, McGraw-Hill Higher Education, 2nd ed. 1988. 7/ 28 8/ 28 EEE118: Lecture 1 EEE118: Lecture 1 Circuits Terminology Circuits Terminology Voltage & Current Nodes and Branches A Node is “A point in a circuit where two or more components are The properties of circuits are described by two important electrically connected.” quantities. A Branch is “A pathway in a circuit through which current may Current , has the units amperes Voltage , has the units volts and flow.” and symbol A. symbol V. Also called “potential It is the rate of flow of electric We talk about “node voltages” and branch “currents”. difference” charge (coulombs per second). It is the energy required to move At the atomic level it relates to Node A Node B R 2 a quantity of charge between two the flow of electrons where 1 potentials. electron has a charge of i 1 One joule of energy is required to 1 . 6 × 10 − 19 C Branch V 1 “raise” one coulomb of charge by R 1 R 3 V 3 1 A = 6 . 241 × 10 18 electrons per I Current R 1 one volt. second Voltage is always measured Current flows through a circuit across two nodes . branch . Node C (Reference) 9/ 28 10/ 28 EEE118: Lecture 1 EEE118: Lecture 1 Units Units Engineering Units Significant Figures & Decimal Places In calculations use the full available precision until the final Engineers and Pure Scientists often use a modified scientific solution is reached. notation called “engineering units”. Non-zero digits are significant Prefix Symbol Multiplier 91 has 2 s.f. and 0 d.p. Writing in engineering units Zeros between two non-zero digits × 10 15 Peta P are significant. makes the magnitude of the unit × 10 12 Tera T 123.45 has 5 s.f. and 2 d.p. easier to understand. × 10 9 Giga G Leading zeros are not significant. 0.00052 has 2 s.f. and 5 d.p. × 10 6 Mega M Trailing zeros in a number 107 µ V is preferable to × 10 3 kilo k 0.000122300 has 7 s.f and 9 d.p. 1 . 07 × 10 − 4 V containing a decimal point are × 10 0 significant. 12.2300 has 6 s.f. and 4 d.p. × 10 − 3 Milli m 20.6 nA is easier than Trailing zeros in a number not 91000 has 2 - 5 s.f. and 0 d.p. × 10 − 6 Micro µ 0.0000000206 A containing a decimal point are × 10 − 9 Nano n ambiguous. 10 MV is clearer than 10 × 10 6 V × 10 − 12 Pico p In engineering we prefer to use significant figures not decimal × 10 − 15 Femto f places. 11/ 28 12/ 28

EEE118: Lecture 1 EEE118: Lecture 1 Passive Components Passive Components Resistors Time Domain Relationship Between Current and Voltage Resistor Construction & Technology Resistors are two terminal circuit elements which dissipate energy as heat. Depends on the component. Carbon Composition Finely powdered I is linearly proportional to V. I = V Resistors R (Ohm’s Law) carbon is mixed with a filler. The more carbon this mix contains the lower the I is the derivative of V. I = C d V resistance. Capacitors d t V is the integral of I. V = 1 � I d t . Carbon/Metal Film A layer of carbon or C metal film is coated on a ceramic rod. The I is the integral of V. I = 1 � V d t . resistance is trimmed by cutting a helix. Inductors L V is the derivative of I. V = L d I d t Wire Wound A thin nichrome wire is wound onto a ceramic rod. 13/ 28 14/ 28 EEE118: Lecture 1 EEE118: Lecture 1 Passive Components Passive Components Resistors Resistors Carbon Composition Carbon Film Tolerance specification ( ± 5 % – ± 1 %). Generally poor tolerance specification ( ± 20 %). Relatively inexpensive due to high production volumes (1 kΩ More expensive than in prior times as production volumes are 0.25 W, £ 0.0078 per unit at 1,000 units). lower, other technologies becoming more dominant. Moderately low “excess noise” compared to other types of Excellent for high energy pulse applications (protection resistor V n ≈ (4 k T R B ) 0 . 5 circuits etc.) as the whole volume conducts current approximately evenly and the resistor has a high “thermal Pulse power dissipation is low because the conducting media is a helix not the whole volume of the part. mass” for its volume. High “excess noise” 3 compared to other types of resistor Continuous power dissipation up to a few watts. √ V n >> 4 k T R B High temperature coefficient ∼ 1 , 000 ppm per ◦ C. £ 0.07 per unit when buying 100 units. 3 Excess resistor noise is often a function of the voltage drop across the resistor. k is Boltzmann’s constant, T is the absolute temperature, R is the resistance and B is the measurement bandwidth. 15/ 28 16/ 28 EEE118: Lecture 1 EEE118: Lecture 1 Passive Components Passive Components Resistors Resistors Metal Film Wire Wound Excellent tolerance specification ( ± 0 . 05 %). More expensive than all others. Excellent tolerance specification ( ± 0 . 05 %) possible. Generally composed of nichrome wire wound round a ceramic Still generally slightly more expensive than carbon film (1 kΩ former. 0.25 W, £ 0.0189 per unit at 1,000 units) Negligible excess noise characteristics V n = (4 k T R B ) 0 . 5 . Generally composed of nichrome, tin oxide or tantalum nitride. Typical applications: high power dissipation loads, current Good excess noise characteristics V n = (4 k T R B ) 0 . 5 (more balancing resistors. or less). Temperature coefficients ranging between less than 10 ppm per ◦ C. Typical applications: bridge circuits, RC oscillators and active Power ratings up to several kW. filters. Temperature coefficients ranging between 10 and 100 ppm per ◦ C. Similar power ratings as carbon film. 17/ 28 18/ 28