Student Notebook The Eli Whitney Museum Electronics Introduction to Electronics Draft Name ___________________________________ Written by: Robert Gagliardi Edited by: John Benton, Stephen Bitar, Christian Wester Revision C -- March 31, 2008 Electronics - Student Eli Whitney Museum Table of Contents Terms & Definitions 2-3 Soldering 4 Units 5 Circuits 6 Ohmʼs Law 7 Resistance 8 Capacitance 9 Diodes 10 Transistors 11 Component List 12-13 Integrated Circuits 15 555 Timer 16 Binary to Decimal Decoder 17 Binary Counter 18 D Flip Flop 19 Logic Gates 20 AND Gates 21 Bar Graph Decoder 22 Projects 23 LED Controller 25 Transistor Controller 27 Light Break Sensor 39 Timer 31 Binary Decoder 33 Binary Counter 35 Stopwatch 37 Voltmeter 39 Notes 40-41 1 Electronics - Student Eli Whitney Museum Terms & Definitions Battery - Two or more connected cells that produce a direct current by converting chemical energy to electrical energy. Binary - Anything composed of two parts. In modern electronic computers, information is stored in banks of components that act like switches. Since switches can be either on or off, they have a binary character, and we say that the computer uses “binary arithmetic” to do its work. Bit - fundamental unit of information having just two possible values, as either of the binary digits 0 or 1. Capacitance - The property of a circuit element that permits it to store charge. Capacitor - An electric circuit element used to store charge temporarily, consisting in general of two metallic plates separated and insulated from each other by a dielectric. Also called condenser. Charge - To cause formation of a net electric charge on or in a conductor. Circuit - A closed path followed or capable of being followed by an electric current. Current - The amount of electric charge flowing past a specified circuit point per unit time. Diode - An electronic device that restricts current flow chiefly to one direction. Electricity - The physical phenomena arising from the behavior of electrons and protons that is caused by the attraction of particles with opposite charges and the repulsion of particles with the same charge. Integrated Circuit (IC) - A complex set of electronic components and their interconnections that are etched or imprinted onto a tiny slice of semiconducting material. 2 Electronics - Student Eli Whitney Museum Resistance - The opposition of a body or substance to current passing through it, resulting in a change of electrical energy into heat or another form of energy. Resistor - A device used to control current in an electric circuit by providing resistance. LED (Light Emitting Diode) - Emits light of a single primary color, but in combination with other diodes can produce colors of any hue for use in signage. These devices, each of which is about one centimeter (half-inch), have a remarkably long life. Schematic - A graphical representation of a system. It often refers to electronic circuits on a printed circuit board. Switch - A device that makes, breaks, or changes the course of an electric circuit. Solder - Any of various fusible alloys, usually tin and lead, used to join metallic parts. Soldering - To unite or repair something with solder. Transistor - A small electronic device containing a semiconductor and having at least three electrical contacts, used in a circuit as an amplifier, detector, or switch. Voltage - Electromotive force or potential difference, usually expressed in volts. 3 Electronics - Student Eli Whitney Museum Soldering Safety Tips: • Always return the iron to the stand when not in use. • Never touch the metal part of the iron. • Use pliers to hold components while soldering. Components will become hot. Good Technique Bad Technique Soldering Tips: • Use only lead free solder. • 21 AWG Rosin Core Pb Free is desirable. • The tip of the iron should be about 700°F for lead free solder. • Work in a well ventilated area. Avoid breathing fumes. • Soldering joints should be shiny and of uniform shape. • “Cold Joints” are characterized by a dull appearance. They are sometimes also misshapen. • Do not blow on joints as this will cause oxidation and cold joints. • Prepare the soldering iron by cleaning it with a damp sponge and then adding a little solder to the tip. This is called tinning. • Use copper tacks as nodes. Avoid loose and sloppy connections. • If the tip of the iron has lost its sheen it can be sanded and then tinned. • Do not sand the tips of expensive irons. They have special metallic coatings that will be ruined by sanding them. First Aid: • If you burn yourself run the burn under cool water for at least five minutes. • Do not put lotions on he burn, it will heal better without it. 4 Electronics - Student Eli Whitney Museum Units • Some examples of units that are used every day are inch, gallon and pound. • For example, the unit of weight is the pound and the unit of resistance is the ohm. • Rather than writing the word pound the abbreviation lbs is used. • Rather than writing the word ohm the abbreviation Ω is used. • 3 volt is written 3V • 47 ohm written 47Ω Quantity Symbol Unit Voltage V Volt Current A Amp Resistance Ω Ohm Capacitance F Farad • Many long numbers like 1,000,000 and 0.000001 are used in electronics. • A long number can be written in a shorter form to take up less space. • The number 47,000 is written 47k • The number 0.0000027 is written 2.7μ Name Symbol Value giga G ×1,000,000,000 mega M ×1,000,000 kilo k ×1,000 milli m ÷1,000 micro μ ÷1,000,000 nano n ÷1,000,000,000 • Sometimes long numbers have to be written with units. • 10,000 ohm is written 10kΩ • 0.0001 farad is written 100μF 5 Electronics - Student Eli Whitney Museum Circuits Complete Circuit • Electricity flows through metal in a complete circle. • It travels from a positive voltage to a negative voltage in the direction the arrow indicates. • This circular path is called a circuit. • Voltage creates a current. Current is flowing electricity. • When electric current travels through the light it turns on. Incomplete Circuit • When there is not a compete circuit current does not flow. • If electricity is not moving through the light it will not turn on. 6 Electronics - Student Eli Whitney Museum Ohmʼs Law V V=I×R I R Voltage = Current × Resistance I 300μA V R 3V 10kΩ V = I × R 3V = 300μA × 10kΩ 330μA 30μA 300 3V μ 10kΩ 100kΩ A 330μA 3V ÷ 10kΩ = 300μA 3V ÷ 100kΩ = 30μA 300μA + 30μA = 330μA 27.3μA + 0.27V 10kΩ - 3V + 2.73V 100kΩ - 10kΩ + 100kΩ = 110kΩ 3V ÷ 110kΩ = 27.3μA 27.3μA × 10kΩ = 0.27V 3V - 0.27V = 2.73V 7 Electronics - Student Eli Whitney Museum Resistors • Resistors limit the flow of current. • Resistors use up voltage as current flows through them. • The unit of resistance is the ohm • Ohm is abbreviated with the symbol Ω 47kΩ ±5% Second Digit Multiplier First Digit 0 ×1 Accuracy 1 1 ×10 ±1% 2 2 ×100 ±2% 3 3 ×1k ±5% 4 4 ×10k ±10% 5 5 ×100k 6 6 ×1M 7 7 ÷10 8 8 ÷100 9 9 Single Series Parallel R1 R1 R2 R1 R2 R1 × R2 R = R1 R = R1 + R2 R = R1 + R2 • R stands for the amount of total resistance. • R1 and R2 stand for the value of resistance of each resistor separately. 8 Electronics - Student Eli Whitney Museum Capacitors • Capacitors store electricity. • Voltage develops across capacitors as they charge. • The unit of capacitance is the farad. • Farad is abbreviated with the symbol F Direction Does Not Matter Direction Matters Charging a Capacitor Discharging a Capacitor R R C C T = seconds for C to charge T = seconds for C to discharge T = R × C T = R × C Single Series Parallel C1 C1 C1 C2 C2 C1 × C2 C = C1 C = C = C1 + C2 C1 + C2 • C stands for the amount of total capacitance • C1 and C2 stand for the value of capacitance of each capacitor separately. 9 Electronics - Student Eli Whitney Museum Diodes • Diodes only allow electricity to flow in one direction. • Current can only flow in the direction the arrow indicates. • Certain types of diodes emit light when current passes through them. They are called Light Emitting Diodes or LEDs for short. Diode LED Light Emitting Diode Diode Characteristics: LED Characteristics: • Diodes have 0.7 volts across them • Different types of LEDs need different when electricity flows. This can amounts of voltage dropped across them sometimes be a problem when to create light. working with a supply voltage of • The 0.7 volt rule mentioned above does three volts. not apply to LEDs. The voltage across the LED depends upon the type of LED and the current passing through it. • To much current can burn out an LED. A resistor in series with an LED will limit the current through it. 10 Electronics - Student Eli Whitney Museum Transistors • Transistors can be used as switches. • When a voltage is applied to the base, the collector and emitter become connected. • Think of the connection between the collector and emitter as a resistor. • The greater the voltage is at the base the less the resistance will be between the collector and emitter. C C High Voltage B E E C C D5041 Medium Voltage B E C B E E E = Emitter C = Collector C C B = Base No Voltage B E E 11 Electronics - Student Eli Whitney Museum Component Symbols Name Symbol Info Battery Ω - Ohm Resistor k - Kilo = ×1,000 M - Mega = ×1,000,000 Connected Wires Unconnected Wires Switch Diode LED 12 Electronics - Student Eli Whitney Museum Name Symbol Info C D5041 Transistor B E C B E C C Phototransistor E E F - Farad Capacitor μ - Micro = ÷1,000,000 Polarized Capacitor Vs Vsupply = Voltage of battery GND Ground = 0 volts 13 Electronics - Student Eli Whitney Museum 14 Electronics - Student Eli Whitney Museum Integrated Circuits Pin Numbering 8-Pin Chip 1 8 4 5 15 Electronics - Student Eli Whitney Museum 555 Timer TS555 GND 1 8 Vs Trigger 2 7 Discharge Output 3 6 Threshold Reset 4 5 Control Vs 7 3 TS555 2 3 6 GND 4 16 Electronics - Student Eli Whitney Museum Binary to 7-Segment Decoder 74HC4543 (Vs) 1 16 Vs 74HC4543 C 2 15 f 5 A a 9 B 3 14 g 3 B b 10 D 4 13 e 2 C c 11 A 5 12 d 4 D d 12 (GND) 6 11 c e 13 Blank 7 10 b 7 Blank f 15 GND 8 9 a g 14 *Display is blank if input Blank is high.