LAB MODULES. MSCI 222C Introduction to Electronics. Charles Rubenstein, Ph. D. Professor of Engineering & Information Science

Transcription

1 MSCI 222C Introduction to Electronics Charles Rubenstein, Ph. D. Professor of Engineering & Information Science LAB MODULES Copyright C.P.Rubenstein

2 Electronics Hands-On Lab - Module 01 MSCI 222C HANDS-ON LAB INSTRUCTION SHEETS MODULE 1 MEASURING RESISTANCE AND VOLTAGE NOTES: 1) Each student will be assigned to a unique Lab Equipment number MS01-MS45 which will match to a Tool Kit and a Radio Shack Electronic Learning Lab Console. 2) All work is to be done individually, There are no "lab reports" in this course. You must turn in the Lab Module Results Sheet(s) once you have reviewed them with the instructor and completed the module. Keep Instruction Sheets for use when studying for exams. 3) Enter all your lab results on both the Instruction Sheets, and the Results Sheet(s). 4) All measurements should be made with the Digital Multimeter in your Pratt Kit. To conserve your multimeter s 9V battery, be sure to turn the meter off if not in use for over 5 minutes. Please check that your meter is turned off and in your Tool Kit when leaving class This first module is designed such that you become familiar with the Radio Shack Electronic Learning Lab Console and breadboard, measuring resistance and voltage with the Multimeter, using the wire stripper and reading basic schematic diagrams. BILL OF MATERIALS Radio Shack Electronic Learning Lab Console AC Adapter ( 9 volts at 150 ma ) Digital Multimeter Wire Stripper Four (4) 1000 Ohm, ½ Watt Resistors with color code: brown black red gold (1KΩ at 5%) Miscellaneous connecting leads and wires SECTION A. USING THE MULTIMETER In the tool kit you will find a Digital Multimeter which should look similar to the one shown in Figure 1.1. The Multimeter will be used in this course for routine measurements of resistance (Ohmmeter) and direct current (DC) voltages (Voltmeter). Your Multimeter is a very powerful tool as it can also measure current, transistor current gain (hfe), and alternating current (AC) voltages. There are two special leads provided with a plug for the Multimeter on one end and a push-in hook on the other. The RED lead plugs into the VΩmA socket and the BLACK lead plugs into the COM socket on the meter. COM is another way of saying common connection, in most cases this is the electrical ground or GROUND for your circuit which is connected to the negative power of your power supply. Figure 1.1 Digital Multimeter Charles Rubenstein. Revision This document is available electronically at:

3 Electronics Hands-On Lab - Module 01 MSCI 222C MEASURING THE RESISTANCE OF RESISTORS CAUTION: Whenever inserting components or measuring resistor values please be sure that the power to your circuit is OFF to avoid damaging your meter. To use your Multimeter to measure the resistance (ohms) it must be set on one of the Ohmmeter function modes in the lower left meter ranges of 200, 2000, 20K, 200K and 2000K ohms. We will measure the resistance of a resistor with the markings: brown black red gold (1 0 x 100 = 1000 ohms = 1KΩ; +/- 5%). We typically select the meter range which is higher than our anticipated value, so in this case use the meter s 2000 range. Use the hook ends of the meter leads to grab the two leads of the resistor. Resistors that we use in this class have NO polarity, so it does not matter which of their two leads is connected to the meter s RED and BLACK hooks. 1a.) What value of resistance do you measure? Ohms If your result is more than 10% off (i.e. less than 900Ω or greater than 1100Ω); Consult your instructor. THE RADIO SHACK ELECTRONIC LEARNING LAB CONSOLE Each student will be assigned to a unique Radio Shack Electronic Learning Lab Console on which to assemble the hands-on labs during the semester without needing to remove and re-wire your circuits every week. NOTE: the AC adapter output voltage, which is controlled by the ON/OFF switch at the Console s upper left, is only available at the five connections between the + and 1 at the upper left of the Console s solderless breadboard per Figure 1.2, below. Figure 1.2 Radio Shack Learning Lab Console Solderless Breadboard Charles Rubenstein. Revision This document is available electronically at:

4 Electronics Hands-On Lab - Module 01 MSCI 222C We will now see how simple it is to insert resistors into the breadboard to interconnect them and make it easier to create temporary circuits without soldering. INSERTING RESISTORS ONTO THE BREADBOARD Gently bend the leads of the 1KΩ resistor you just measured the resistance of close to the device s body to form a U and insert the resistor (R1) into the breadboard s connection points A25 and F25 with four (4) empty rows (B, C, D, and E) between the two leads (see Figure 1.2). NOTE: These connection points are in the fifth column of breadboard in the last column, the fifth connection at the top (A25) and sixth row from the top (F25) connection points. Note, too, that the four connection points to the left of both A25 (that is A21-A24) and F25 (that is F21-F24) allow up to four more connections to each of those leads. This results in the schematic and pin locations of Figure 1.3. Recall that there is NO polarity for our resistors although having the gold band at the lower end looks nice. Figure 1.3 One Resistor Circuit Schematic with Console Breadboard Connection Points Indicated 1b.) Repeat your resistance measurement (A25 to F25) Ohms Did you read the same value as in 1a? YES or NO? NOTE: Occasionally we may find slight differences in measurements made directly, and those made with components in circuit, but in this case the readings should be the same as nothing else is connected to the resistor at this time. MEASURING THE RESISTANCE OF TWO RESISTORS IN SERIES Now bend and insert a second brown black red gold (1KΩ = 1000 ohms at 5%) resistor (R2) into the breadboard at pin connections F23 and K23 to create the two resistor series circuit shown in Figure Figure 1.4 Two Resistor Schematic with Console Breadboard Connection Points Indicated Note that the pins numbers at the right are where the component leads are inserted and the pin numbers at the left are used for measuring the resistance in this circuit. Using the Multimeter on either the 20K or 2000 scale at the lower left, measure the resistance of two 1KΩ resistors in series by measuring between A21 and K21. Using the 20K scale 1000 ohms would read 1.00 (rather than 1000 on the 2000 scale). 1c.) Resistance of two 1KΩ resistors in series ohms If the resistance is not nearly 2000 ohms; Consult your instructor Charles Rubenstein. Revision This document is available electronically at:

5 Electronics Hands-On Lab - Module 01 MSCI 222C MEASURING THE RESISTANCE OF TWO RESISTORS IN PARALLEL Now bend and insert a third brown black red gold (1KΩ = 1000 ohms at 5%) resistor (R3) into the breadboard at A21 and F21 to create a two-resistor parallel circuit with the resistor in A25 - F25 as indicated in Figure 1.5. NOTE: DO NOT REMOVE RESISTOR R2 (BETWEEN F23 AND K23)!!! Figure 1.5 Resistor Schematic with Console Breadboard Connection Points Indicated Use the Multimeter on the 2000 scale at the lower left to measure the resistance of the two 1KΩ resistors R1 and R3 in parallel between A21 and F21 (NOT K21). Note: Pins A21 through A25 are connected together internally as are F21 through F25. 1d.) Resistance of two 1KΩ resistors in parallel ohms If the resistance is not nearly 500 ohms; consult your instructor. FOUR RESISTOR SERIES CIRCUIT Carefully remove resistor R3 from the breadboard at A21 and F21 and insert it instead between points K25 and P25 creating a three-resistor series circuit. Finally, bend and insert a fourth brown black red gold (1KΩ = 1000 ohms at 5%) resistor (R4) between P23 and T23 to create a four-resistor series circuit as indicated in Figure 1.6. Figure 1.6 Four Resistor Series Circuit with Console Breadboard Connection Points Indicated Using the Multimeter on the 20K scale at the lower left, measure the resistance in KΩ of the four 1KΩ resistors R1 through R4 in series between A21 and T21. Note: Pins A21 through A25 are connected together internally as are T21 through T25. 1e.) Resistance of four 1KΩ resistors in series ohms If the resistance is not nearly 4000 ohms; consult your instructor. DO NOT REMOVE THESE RESISTORS! Instructor Check Point 1A Charles Rubenstein. Revision This document is available electronically at:

6 Electronics Hands-On Lab - Module 01 MSCI 222C SECTION B. LEADS, WIRES AND MEASURING VOLTAGES USING INSULATED WIRE TO CONNECT DEVICES To interconnect components on the Console we use #22 gage insulated wire in one of three colors, RED for direct connections to positive power voltage, BLACK for direct connections to electrical ground, and YELLOW for all other interconnections. Cut a three (3) inch length from the RED wire spool with the cutting portion of the wire stripper. Now carefully close your wire stripper around the wire insulation about 0.25 from one end while at the same time pulling the remaining length of wire. The hope is that you will remove the insulation without nicking or cutting the wire itself. Do this on both sides, and as needed, with several other lengths of wire until you get the feel for removing just the insulation without damaging the wire. Although a quarter inch is enough bare wire for inserting into the connection points on the breadboard, you will probably need more like a half inch of bare wire for effective connections to the various springs used to connect to the Console s many internal components. BARE WIRE FOR EASY POWER CONNECTIONS Carefully remove ALL the insulation from the three-inch piece of wire. Then cut this piece of now bare wire into one-inch lengths and bend each into a U loop. Connect one loop to a pair of connection points between the leftmost + sign and the 1 power label (e.g., pins 2 and 4, see Figure 1.2) to permit easy access to the AC Adapter power with the RED alligator clip. Insert a second loop of wire into any pair of the GROUND connections at the bottom of the breadboard for connecting to the BLACK alligator clip. You now have an easy way to connect your resistors to positive or plus voltage and ground with these two alligator clips. A third wire loop can be placed into any pair of the 25 connections between 1 and the rightmost + sign for use in checking that voltage (currently zero, these will become the 5 volt regulated voltage source connections). USING YOUR AC ADAPTER AS A POWER SOURCE The Console has been modified to accept a 9 volt, 150 milliampere AC Adapter for use in powering your circuits. Modifications have also been made to allow the ON-OFF Switch at the top left to control power from the adapter connecting to the centrally mounted solderless breadboard. MEASURING VOLTAGES To use your Digital Multimeter to measure the voltage (in volts) available on the console breadboard it must be set up in the Voltmeter function mode with the rotary switch set on one of the upper right-hand DC Voltage ranges: 200m, 2000m (2000 millivolts = 2 volts), 20, 200, and As we expect the AC Adapter output voltage to be 9-17 volts, use the 20 range with the RED lead from the meter connected directly (or via a RED alligator clip lead) to the loop inserted into a pair of the five connection points at the top left of the breadboard, and the BLACK lead from the meter connected directly (or via a BLACK alligator clip lead) to a loop inserted into any pair of the thirty (30) connection points at the bottom of the breadboard (electrical GROUND). All voltage measurements should be positive. The voltmeter will show a negative voltage if your polarity is reversed, if that happens, please reverse the lead connection Charles Rubenstein. Revision This document is available electronically at:

7 Electronics Hands-On Lab - Module 01 MSCI 222C MEASURING UNLOADED AC ADAPTER POWER SUPPLY VOLTAGE Find the Console s rear-mounted socket connector and plug your 9V cube adapter into it and then plug your adapter into the AC power strip on your desk. When the Power Strip and Console switches are both in the ON position the output of the AC Adapter is connected directly to the leftmost top five connecting points (labeled V volts on the figure, but NOT on the actual breadboard, where they are between the + sign and number 1, see Figure 1.2 on page 2. The AC Adapter was designed to deliver 9 volts at 150 milliamperes (0.150 Amperes). The adapter voltage output is variable: when less current is drawn from it the output will be greater than 9 volts. Without ANY load, that is open circuited or UNLOADED, the adapter voltage should be between 9 and 17 volts. We will be calling V1 the AC Adapter s unregulated voltage. Make your measurement of the AC Adapter s unloaded, unregulated, voltage V1 using the 20 volt range (upper left BLUE scales) on the Multimeter. 1f.) 9V cube adapter unloaded voltage (9-17V expected without a load) volts MEASURING RESISTOR VOLTAGES AND LOADING EFFECTS You have already created a four-resistor series circuit on your Console Breadboard using four each 1000 Ohm resistors per Figure 1.6 on Page 4. Cut and strip a piece of RED wire and connect it to one of the five positive V1 voltage connection points between the rightmost + and 1 and connect the other end to any open connection in the row A21-A25. ALWAYS use RED wires or leads for + voltages. Cut and strip a piece of BLACK wire and connect it to one of the ground points at the bottom of the Console Breadboard. Wires connecting ground should be BLACK. VOLTAGE DIVIDER PROOF Referring to Figure 1.6 on page 4, the RED wire at A21 and BLACK wire at T21 (across all four resistors), measure the voltage drop across each individual 1KΩ resistor: 1g1.) R1: A21 to F21: volts 1g3.) R3: K21 to P21: volts 1g2.) R2: F21 to K21: volts 1g4.) R4: P21 to T21: volts MEASURING RESISTOR VOLTAGE LOADING EFFECTS Now measure the adapter output voltages keeping the RED lead at A21 and connecting the BLACK wire to T21, P21, K21 and F21 as noted: 1h1.) A four series 1KΩ resistor = 4000Ω load, BLACK at T21: volts 1h2.) A three series 1KΩ resistor = 3000Ω load, BLACK at P21: volts 1h3.) A two series 1KΩ resistor = 2000Ω load, BLACK at K21: volts 1h4.) A 1KΩ resistor = 1000Ω load, BLACK at F21: volts 1h5.) Does adding the (four) individual voltage drops 1g1 though 1g4 equal the same voltage you found in the four-resistor load circuit of 1h1? (Yes or No?) DO NOT REMOVE THE RESISTORS - YOU NEED THEM NEXT WEEK This is Instructor Check Point 1B Charles Rubenstein. Revision This document is available electronically at:

8 Electronics Hands-On Lab Module 02 MSCI222C HANDS-ON LAB INSTRUCTION SHEET MODULE 2 VOLTAGE SOURCES, LEDS, DIODES & CHARACTERISTIC CURVES NOTES: 1) To conserve the life of the Multimeter s 9 volt battery, be sure to turn the meter off if not in use for over 5 minutes. Always double check that the multimeter is off when finishing your work, or leaving class. 2) All work is to be done individually. All results are to be written on these sheets AND on the Results Sheet(s) which should be submitted after the Instructor reviews each completed Module. Always keep these Instruction sheets on file for review. There are no "lab reports" in this course only handed in results sheets. 3) If you did not finish Module 1, be sure to finish it NOW before starting this Module or you will fall behind the rest of the class. Labs need to be done in order. BILL OF MATERIALS Radio Shack Electronic Learning Lab Console, AC Adapter (9 volts at 150 ma), Digital Multimeter, Wire Stripper, Miscellaneous Connecting leads and wires (Standard for all labs) (1) Green LED (1) 1N4007 Rectifier Diode (Black body, resistor type device with Silver stripe) (4) 1000 Ohm, ½ Watt Resistors with color code: brown black red gold (1KΩ at 5%) (1) 10Kohm, ½ Watt Resistor with color code: brown black orange gold (10KΩ at 5%) (1) 100Kohm, ½ Watt Resistor with color code: brown black yellow gold (100KΩ at 5%) USING THE DIGITAL MULTIMETER Your digital Multimeter has many functions it can operate as an AC (alternating current) or DC (direct current) Voltmeter for measuring voltages across a device, a DC Ammeter for measuring currents through a device, as an Ohmmeter for measuring the resistance of a device (with the power OFF!), a diode and transistor hfe gain checking device. We will only use it for DC voltage, resistance, and diode testing in this course. Always connect the RED test lead to VΩmA jack and the BLACK lead to COM jack. Multimeter DC Voltage Measurement - Set the rotary switch at the desired position. If the voltage to be measured is not known, set the range switch at the highest range (Left BLUE Scale) position and then reduce it until a satisfactory measurement is obtained. - Connect the test leads across the source or load being measured. - Read the voltage value and polarity on the LCD display. (Negative voltages indicate that the RED and BLACK leads are probably reversed.) Multimeter Resistance Measurement Note: If the resistor being measured is connected to a circuit, ALWAYS turn off power and discharge all capacitors before applying meter leads! Our resistors have no polarity and there should not be a negative sign on the display. - Set the rotary switch at desired resistance range (Lower Left GREEN Scale) position. - Connect the test leads across the resistance to be measured and read the LCD display. If a 1 is shown on the display it indicates over-range lower the scale Charles Rubenstein. Revision : This document is available electronically at:

9 Electronics Hands-On Lab Module 02 MSCI222C Multimeter Diode Testing The polarity of red lead is positive "+ in this mode. - Set the rotary switch to diode test (Lower Right BLACK Scale, diode symbol). - Connect the RED lead to the anode of the diode to be tested and the BLACK lead to the cathode silver band side of the diode. - The forward voltage drop of the diode will be displayed in mv. For a good diode this is and when the connection is reversed, the figure "1" should be displayed. Bad diodes will have the same values in both directions: if shorted: a very low voltage drop ( ) or if open circuited a "1" at left of scale. 1. VOLTAGE SOURCES NOTE: Your AC Adapter is an unregulated power supply. To get a constant output voltage a regulated supply can be used. In Hands-on Module 4 we will create a voltage regulator circuit to provide a constant 5.0 volts for varying loads. 1.1) Plug your adapter into the Console and then into the AC power strip. 1.2) Set your Multimeter on the 20 volts DC scale (upper left BLUE scales) and connect the red lead to one of the top left five unregulated voltage connections and the black lead to one of the 30 ground connections on the Console Breadboard Turn the Console Power Switch at the top left to the ON position. The AC adapter is rated at 9 volts DC at 150 ma. 1.a) What is the unloaded unregulated source voltage, V? volts 1.4) Without disconnecting your meter, connect the 10K ohm potentiometer in parallel across the power supply with a red wire between Spring #37 and one of the remaining unregulated voltage connections and a black wire between Spring #39 and a ground connection as seen in Figure 1. 1.b) What is the loaded unregulated source voltage, V, between Spring 37 (+) and Spring 39 (ground)? volts Do NOT disconnect this circuit Figure 2.1. Variable Power Supply 2. CREATING A VARIABLE VOLTAGE SOURCE The AC adapter has no controls to set its voltage. Its output voltage as seen above is controlled by the resistance of its load. The circuit of Figure 2.1 is often called a voltage divider since the voltage is divided across (in this simple case) two resistors or in the case of the potentiometer, resistance between Spring #37 and #38 and resistance between Spring #38 and #39. If we connect the Multimeter between the 10K ohm potentiometer s variable wiper at Spring #38 and ground (Spring #39) we can adjust the unloaded voltage Vo from zero to at least 9 volts by rotating the potentiometer s dial Set the dial on the 10KΩ potentiometer such that the DC Voltage between Springs #38 and #39 is 5.0 (+/- 0.1) volts. Turn OFF the power. Without changing any wiring reset the Multimeter dial to read resistance on the 20K scale (lower left GREEN Scale). 2.a) What is the resistance of the potentiometer for Vo = 5.0 volts? KΩ Return the Multimeter range dial to 20 volts DC before turning power back ON! Charles Rubenstein. Revision : This document is available electronically at:

10 Electronics Hands-On Lab Module 02 MSCI222C THE LIGHT EMITTING DIODE 3. MEASURING THE VOLTAGES ACROSS LEDS It is very common to use resistors in series with a device to reduce the overall voltage and current in a circuit. There are two GREEN LEDs and one RED LED in your parts kit. We will insert these one at a time into our Voltage Divider circuit and see what the voltage drop across each LED diode is in a working circuit. This is NOT the same as a 1N4007 rectifier diode s forward biased voltage drop as will become evident in the next section on Diodes and Rectifiers. Figure 2.2. Variable Power Source and LED 3.1) With the 10KΩ potentiometer still set such that the DC Voltage between Springs #38 and #39 is 5.0 (+/- 0.1) volts, connect a black wire from the ground or Spring #39 to a convenient row of five connectors on the Breadboard (e.g., T15). Insert one of the Green LEDs into the Breadboard with the lead on its FLAT side in T11 and the other lead in T10. Now take a red wire and connect it between Spring #38 and connection T6. Turn ON the Power Switch and read the voltage Vo with an LED load. 3.a) What is the variable source voltage, Vo across the LED? volts 3.b) Does the LED light up? Yes No 3.c) What is the lowest voltage, Vo across the LED for it to light up? volts This is instructor checkpoint 2A. DIODES AND RECTIFIERS 4. THE FORWARD BIASED RECTIFIER DIODE Turn OFF the Console and Multimeter. To wire the circuit of Figure 2.3, find the type 1N4007 silicon rectifier diode in your parts kit (the diode is similar in size to your resistors, but it has a BLACK body on which there is a single SILVER band which indicates the diode s cathode). Connect the silver band side to tie point T3 and the other side to P3. Connect the RED power wire that was connected to Spring #37 (at the potentiometer) to tie point P1. Leave the black (ground) wire connected to T15. The Green LED between tie points T10 and T11 is NOT changed. Connect a 1Kohm resistor between T5 and T9. Figure 2.3. Forward Biased Diode 4.a) Does the LED light? Yes No If the LED does NOT light, check your circuit for errors Charles Rubenstein. Revision : This document is available electronically at:

11 Electronics Hands-On Lab Module 02 MSCI222C 4.2 Turn ON the Multimeter, use the 20 DC volts scale to make these measurements: 4.b) What is the voltage VLED measured across the LED? volts 4.c) What is the voltage VD measured across the diode? volts 4.d) What is the voltage VR1 measured across the 1000 ohm resistor? volts 4.e) What is the loaded unregulated source voltage, V? volts 5. THE REVERSE BIASED DIODE *** Turn OFF the Console and Multimeter Reverse the diode connections (now the silver band should be connected to tie point P3) creating the reversebiased diode circuit of Figure 2.4 *** Turn ON the Console and Multimeter. 5.a) Does the LED light up? Yes No Fig 2.4 Reverse-Biased Diode 5.b) Use your multimeter to measure the voltage across the reverse-biased diode: volts 6. I-V CHARACTERISTIC CURVES Diodes, LEDs and resistors have two connections and are called two-terminal devices. If we were to design circuits for their maximum efficiency we would do so using characteristic curves to match the device to the current (I) and voltage (V) available in a specific circuit. A circuit for measuring the current and voltage of a resistor, and its characteristic curve show the typical resistor to have a positive slope whose value is V/I the device s resistance calculated according to Ohms Law! Fig 2.5 Characteristic Curve Measuring Circuit Fig 2.6 I-V Curve for a Resistor Fig 2.7 Diode Characteristic Curve Circuit 4 Fig 2.8 I-V Curve for a Diode 2018 Charles Rubenstein. Revision : This document is available electronically at:

12 Electronics Hands-On Lab Module 02 MSCI222C Although the resistor s IV curve in Figure 2.6 is linear, Figure 2.8 shows that the IV curve for the diode is NOT linear. In fact, the reverse-biased current is typically measured in microamperes until breakdown of the device occurs (breakdown = destruction here). Zener diodes are specifically designed diodes whose breakdown voltages are precise and are designed to be usable in voltage regulators. Forward-biased silicon diodes have a knee in the range of volts which must be accounted for in circuit calculations We will use the value 0.6 volts for all silicon PN junctions. DIODE I-V CHARACTERISTIC CURVES 6.1) Referring to Figure 2.9 we will measure the voltage across a type 1N4007 rectifier diode (black body with silver stripe) as a function of current. Our 9 volt AC adapter supply voltage, when loaded, yields about 8-17 volts. We will measure the diode voltage drop VD directly across the diode and also the resistor voltage drop directly across a known R1. KCL tells us that the diode current ID is the same as the resistor current IR. Fill in the data for Table 2.1 (below) showing on each line the values for the resistance R1, and the measured voltages across the resistor and diode. Then calculate the current IR = ID in ma. Fig 2.9. Diode Test Circuit The schematic symbol in Figure 2.9 at the bottom of diode D1 is called the ground or sometimes the common ground (we use BLACK wires to connect to ground). To create the various resistance values for R1 shown in Figure 2.9, we use the following ½ watt resistors from the Pratt kit: 100K Ω [brown black yellow gold] 10K Ω [brown black orange gold] 1K Ω [brown black red gold] * (* To create resistances lower than 1KΩ we use two (2) 1K resistors in parallel to create a 500 Ω resistance, we use three (3) 1K resistors in parallel to create 333 Ω and we use four (4) 1K resistors in parallel for 250 Ω. Enter your results, both measured and calculated, on the next page of the Instruction Sheet for future reference, and on the Results page (which you hand in when the lab is completed.) Charles Rubenstein. Revision : This document is available electronically at:

13 Electronics Hands-On Lab Module 02 MSCI222C R 1 100KΩ 10KΩ 1KΩ 500 Ω (2@1K) 333 Ω (3@1K) 250 Ω (4@1K) VD diode voltage (measured) * VR1 resistor voltage (measured) I = VR1 / R 1 current - ma (calculated) NOTE: Whenever applying the equation I = V/R or V = IR or R = V/I remember that V R is the voltage measured across resistor R I D = I R is the current calculated through resistor R When Resistance is in KΩ and Voltage is in volts, Current is always in ma. This is Instructor check point 2B. After making your calculations, plot the I-V Characteristic Curve for the 1N4007 diode. * If the voltage measured across the 1N4007 diode is less than 0.45 volts or greater than 0.8 volts consult your instructor. BEFORE you take the circuit apart, please have your instructor review your setup for the last data set of measurements - in case repeat measurements are needed I(mA) V(volts) RESISTOR NOTES Charles Rubenstein. Revision : This document is available electronically at:

14 Electronics Hands-On Lab Module 03 MSCI 222C HANDS-ON LAB INSTRUCTION SHEET MODULE 3 CAPACITORS, TIME CONSTANTS AND TRANSISTOR GAIN NOTES: 1) To conserve the life of the Multimeter s 9 volt battery, be sure to turn the meter off if not in use for over 5 minutes. Always double check the unit is off when finishing your work, or leaving the classroom. 2) All work is to be done individually and submitted before you leave 3) If you did not finish Hands-on Module 2, be sure to finish it NOW! before starting Module 3. 4) Always keep the Instruction sheets. 5) Enter your Kit # in the upper right corners of ALL RESULTS sheets. BILL OF MATERIALS Radio Shack Electronic Learning Lab Console, AC Adapter (9 volts at 150 ma), Digital Multimeter, Wire Stripper, Miscellaneous Connecting leads and wires (Standard for all labs) (1) Red or Green LED (1) 2N5551 NPN Silicon Transistor (1) 1000 Ohm, ½ Watt Resistor with color code: brown black red gold (1KΩ at 5%) (1) 100Kohm, ½ Watt Resistor with color code: brown black yellow gold (100KΩ at 5%) (1) 100µF Electrolytic Capacitor CAPACITORS Capacitors, as discussed in class, hold a charge on two metal plates separated by an insulator. The larger the capacitance, the larger the amount of charge that can be stored, to the point that, as we will see in today s lab, a 100 microfarad (100µF) electrolytic capacitor can be viewed as a temporary voltage source! CHARGING A CAPACITOR 1. Wire the circuit of Figure 3.1 using a 100,000 ohm (100KΩ) resistor and a 100 µf capacitor (note that the shorter lead - or the one on the side of the white stripe - is the Negative lead) using the unregulated voltage VUNREG (available at the top left 5 connection points and controlled by the Console Power switch) as the voltage V. 1.1 To make connections and disconnections simpler, Fig 3.1. Capacitor Charging Circuit we will use the double-pole/double-throw DPDT Switch (Springs #43 #45) and SPST push button S1 (Springs #46 and #47) to connect parts of this circuit and enable us to easily short out the capacitor. Using Figure 3.4 on page 3 as a guide, connect a RED wire from the unregulated voltage V (e.g., the top left voltage connection at 5 ) to Spring #43 and connect a YELLOW wire from Spring #44 to Breadboard connection T11. Insert a 100KΩ resistor [brown-black-yellow-gold] between connections T13 and T18. Use a YELLOW wire to connect between T20 and Spring #46. Connect a BLACK wire between Spring #45 and Spring #47 and another BLACK wire from Spring #47 to ground. Connect the 100µF capacitor between Spring #46 and Spring #47 (negative lead). Now connect the Multimeter s RED (+) lead to Spring #46 and the BLACK (-) lead to Spring #47. Set the meter to the 20V range and place the DPDT Switch in the UP position Charles Rubenstein. Revision This file is available electronically at:

15 Electronics Hands-On Lab Module 03 MSCI 222C THE TIME CONSTANT TAU or τ The time constant Tau for this circuit is calculated as τ = RC = 10 seconds (100E3 ohms) x (100E-6 farads) = (100,000) x ( ) = 10 s 1.2 Turn the Console Power ON. You should see the voltage increasing slowly. Press the S1 push button to short the capacitor for a few seconds such that the Vinitial starting voltage will be zero. Release the short at t = 0. As best you can, record the voltages at 10 and 50 seconds and average three values of voltage across the capacitor for each time measurement Charles Rubenstein. Revision This file is available electronically at: Fig 3.2. Short the Capacitor 3.1a) Voltage across capacitor after one Tau = 10 seconds is Vc@τ = volts 3.1b) Voltage across capacitor after five Tau = 50 seconds is Vc@5τ = volts 3.1c) Record the unregulated voltage after at least two minutes Vunreg = volts Measured Versus Theoretical Values: The theoretical capacitor voltage after oneτ should be 63% of the supply voltage Vunreg. 3.1d) Calculate your actual One Tau voltage % at 10 seconds: Vc@τ / Vunreg x 100% = % The theoretical capacitor voltage after fiveτ should be 99% of the supply voltage Vunreg. 3.1e) Calculate your actual Five Tau voltage % at 50 seconds; Vc@5τ / Vunreg x 100% = % We expect the experimentally measured values to be less than the theoretical values of 63% and 99% respectively due to meter resistance, component value tolerances and leakage current in the electrolytic capacitor. DISCHARGING A CAPACITOR 2. Using the current circuit, charge the capacitor to as close to 10.0 volts as you can and then disconnect it from the circuit by removing the RED wire between Spring #44 and T11. Leave the meter and all other components and wires connected. Watch the capacitor voltage on the meter as it drops, very slowly, due to the meter s one megohm internal resistance. It could take 10 minutes to go to zero volts. Instead, we will wait until the voltage across the capacitor is 3.7 volts. This is the value for Tau for the circuit from which we could calculate the meter s actual internal equivalent resistance. If you do not reach 3.7 volts after about 2 minutes of discharging there is an error. This RC circuit is shown as Figure a) How long does it take to discharge to 3.7 volts without R1? seconds 2.1) Reconnect the RED wire from T11 to Spring #44 and once again charge the capacitor to exactly 10.0 volts. This time push the DPDT Switch DOWN (see Figure 3.5) for exactly 10.0 seconds, as best you can, and read the voltage on the meter (you might also try this with the BLACK Meter lead disconnected to reduce the error of the parallel 1MΩ Multimeter resistance which results in an Ractual 90KΩ). Figure 3.3. Discharging Capacitors

16 Electronics Hands-On Lab Module 03 MSCI 222C 3.2b) What is your measured value of after one Tau? volts Repeat this experimental procedure to find the 5 Tau voltage: DPDT UP, charge capacitor to 10.0 volts. DPDT DOWN, allow 5 Tau or 50 seconds of discharge into the 100K resistor with meter connected. Disconnect the resistor and measure the capacitor voltage. We expect an answer near the final value of zero volts. 3.2c) What voltage did you find for Vc@5τ after five Tau? volts This is Instructor check point 3A. After your work is checked you may remove the wires from the above circuit. Note: There are many reasons for errors in this experiment. Do not be discouraged if you did not come close to theoretical values. The important thing is to be aware of how capacitors can be used to introduce delays. CONSOLE WIRING DIAGRAM CHARGING THE CAPACITOR Figure 3.4. Possible Console Breadboard Layout of Capacitor Charging Schematic CONSOLE WIRING DIAGRAM DISCHARGING THE CAPACITOR 3 Figure 3.5. Possible Console Breadboard Layout of Capacitor Discharging Schematic 2018 Charles Rubenstein. Revision This file is available electronically at:

17 Electronics Hands-On Lab Module 03 MSCI 222C USING SPECIFIC BREADBOARD TIE POINTS Please note that the Console Breadboard has tie points across the top which also connect in groups of 5 across with the first five being internally connected to the 9VDC AC Adapter. In next week s lab we will create a voltage regulator for this unregulated power supply which we will connect to the other 25 connections at the top of the Breadboard. All 30 connections across the bottom are used as a common ground as they are ALL interconnected. All other connection holes are uniquely identified by their Row (A T) from top to bottom and their Column (1-30) from left to right (see Figure 3.6 below). The left topmost pin (not counting the power 1-5 sets of strips) would therefore be A1, the rightmost topmost pin being pin A30. Similarly, above the ground strip, the left bottom pin would be T1 and T30 at bottom right. VUNREG A27 A30 Ground R30 S30 T30 Fig 3.6. Radio Shack Electronic Learning Lab Breadboard MEASURING THE CURRENT GAIN OF A TRANSISTOR 3) As we saw earlier, a potentiometer - commonly called a pot - is a circular resistor with an internal slider and a knob you can rotate to move the slider from one end of the resistor to the other. We ll use the 10K pot on the console (at the lower left). Connect the bottom of the pot (Spring #39) to one of the ground pins at the bottom row of pins on the Breadboard with a black wire, and the top of the 10Kohm pot (Spring #37) with a red wire connected to the unregulated positive supply voltage at the top left connection at 5. Connect your multimeter as a voltmeter with the red lead to the 10Kohm pot slider Spring #38, and black lead to Spring #39). In the future we will not specify every connector spring # or breadboard point but it may be helpful during your initial work 3.3a) Turn the Power Switch ON and use the 10Kohm pot knob to adjust the voltage from 0 to full supply voltage. Did this work? ( YES NO) If this doesn t work ask for help NOW Charles Rubenstein. Revision This file is available electronically at:

18 Electronics Hands-On Lab Module 03 MSCI 222C 3.1) Find the type 2N5551 transistor in the pink foam compartment of your parts kit. This is a semiconductor manufactured in a small black plastic (TO-92) case see figures below right. It has three (3) inline wire leads internally connected to the NPN Bipolar Junction Transistor s Emitter (E), Base (B) and Collector (C). 3.2) The circuit we are going to set up is somewhat similar to the one in the middle of the page on page 54 of the Electronic Workbook 1, but there are enough differences so that we will use a different placement of parts. Refer to Figure Figure 3.7. Current Gain Measurement Circuit THEORY and CIRCUIT CONSTRUCTION The current gain hfe of a transistor can be measured by dividing the current flowing in the device s collector lead (IC) by the current flowing in the device s base lead (IB) The overall formula for current gain is thus: hfe = IC / IB (Figure 3.7 shows two fixed resistors, 1Kohm and 100Kohm, in addition to the 10Kohm pot. Note that IB=VR2/100K the current through the 100Kohm resistor - between the pot slider (center spring of pot), and the base B (center pin) of the 2N5551 transistor.) 3.3) Turn the input power (VUNREG = VCC) OFF (Console Power Switch DOWN). Insert the transistor (flat side facing to the right) into breadboard holes R30, S30 and T30. This means that the 2N5551 s Collector, in pin R30, is available for direct interconnections at R26, R27, R28, and R29. Likewise, connections can be made to the Base at S26, S27, S28, and S29, and connections to the Emitter can be made at T26, T27, T28, and T ) Connect a 100Kohm resistor between S26 - the 2N5551 transistor s Base (S30) and S20. Use a YELLOW wire at S16 to connect the 100Kohm resistor to the slider Spring #38 on the 10Kohm pot. You already connected the 10Kohm pot Spring #37 to VCC with a RED wire and Spring #39 to ground with a BLACK wire (Figure 3.8 shows a possible circuit layout.) 3.3) Connect the Emitter (T30) to ground with a BLACK wire from T ) Now connect the Collector (R30) to the voltage supply through a 1Kohm resistor and an individual red LED. The red LED should be inserted into A30 and C30 with the shorter wire on the FLAT side (cathode=negative terminal) into C30. The 1Kohm resistor then can be inserted between C29 and R29 at the transistor s collector (using a yellow wire if needed) Charles Rubenstein. Revision This file is available electronically at:

19 Electronics Hands-On Lab Module 03 MSCI 222C 3.5) Turn the unregulated input power (VCC) ON (Power Switch up). 3.3b) Using the 10Kohm pot knob adjust the voltage available to the 100K resistor in the transistor s base circuit. It should be possible to vary the brightness of the LED in the collector circuit. Did this work? ( YES NO) Instructor check point 3B Demonstrate this circuit to your instructor. TAKING THE IC = 5 ma MEASUREMENTS 4) Connect your multimeter as a voltmeter across R3 the 1Kohm collector resistor and adjust the 10Kohm pot to get VR3 to approximately equal 5.0 volts across R3 the 1Kohm resistor. (As usual a reading with a minus sign means you have the leads backwards.) Note that this adjustment gives you approximately VR3/ R3 = 5 ma of collector current. 3.4a) Measure the voltage VR2 across R2 (the 100Kohm resistor connected to the base). The voltage VR2 is: volts (measured). 3.4b) Measure VBE the voltage from point B (base) to point E (emitter) note that the emitter is at ground. The voltage VBE is: volts (measured). 3.4c) Calculate the base current using Ohm s Law [I = V/R = VR2/ R2]: IB = ma (Remember that volts / Kohms = ma) 3.4d) Knowing the collector and base currents, calculate the current gain hfe = ( IC / IB ) hfe = (a number without units) Fill in the 5 ma collector current values for the transistor on the first line of Table 3.1. Instructor check point 3C. Show above to instructor as soon as you have it. 3.4e) Change the 10Kohms pot position to set VR3 to be 2.0 volts across R3. Measure the voltage across R2, and then measure VBE and fill in the second line of Table f) Change the 10Kohms pot position to set VR3 to be 1.0 volts across R3. Measure the voltage across R2, and then measure VBE and fill in the third line of Table 3.1. Then calculate the remaining IB values, in ma., and the dimensionless hfe I C V R2 I B (ma) = VR2 / 100K V BE h FE 5 ma 2 ma 1 ma Table 3.1. Current Gain Measurements 5) You should have found that hfe is reasonably constant, i.e., the collector current is roughly proportional to base current. On the other hand, a slight change in base-emitter voltage should make a large change in collector current. The base-emitter voltage is the forward biased voltage drop across the base-emitter junction. This value should be on the order of 0.6 volts the same value you found for silicon diodes in previous experiments. Keep this Instruction Sheet for your records Parts of this circuit are used in Lab Module 4 Do Not Remove! Charles Rubenstein. Revision This file is available electronically at:

20 Electronics Hands-On Lab Module 03 MSCI 222C CONSOLE WIRING DIAGRAM TRANSISTOR GAIN MEASUREMENTS Figure 3.8. Possible Console Breadboard Layout for Figure 3.7 The circuit above illustrates one possible configuration for the Current Gain Measurement Circuit of Figure 3.7 on Page 6. METHOD FOR SIMPLIFYING VOLTAGE MEASUREMENTS You will note that in this module you are being asked to measure VR3 across the collector resistor, VR2 across the resistor in the base circuit and VBE the base-emitter junction voltage for three different collector current values (5 ma, 2mA, and 1mA) and then to use these to calculate the base current IB and then the hfe of a 2N5551 Silicon NPN Transistor. The first step has you setting the voltage VR3 across the 1KΩ collector resistor. Resistor R3 (per the diagram above) is connected between C29 and R29 and is flat on top of the Breadboard. Place the Multimeter RED lead on the resistor lead connected to C29 and the BLACK lead on the resistor lead connected to R29 to make this measurement. Next measure VR2 across the 100KΩ base resistor between S22 and S27 - note that it is high above the Breadboard. Attach the Multimeter s leads to this resistor s leads (ignore the polarity) and merely record the voltage on the Table. Note that the resistor lead in S27 is already at the base of the transistor. To measure the baseemitter voltage VBE leave one Multimeter lead at S27 and place the other lead at ground for this measurement. After all measurements are made the base current is calculated using Ohm s Law dividing VR2 / 100KΩ = IB and the transistor gain by dividing the currents IC / IB = hfe and including those values in the Table Charles Rubenstein. Revision This file is available electronically at:

21 Electronics Hands-on Lab Module 04 MSCI 222C HANDS-ON LAB INSTRUCTION SHEET MODULE 4 VOLTAGE REGULATION AND TRANSISTOR SWITCHING NOTES: 1) To conserve the life of the Multimeter s 9 volt battery, be sure to turn the meter off if not in use for over 5 minutes. Always double check the unit is off when finishing your work, or leaving the classroom. 2) All work is to be done individually and submitted before you leave 3) If you did not finish earlier Hands-on Modules, be sure to finish them in their number order prior to starting this Module. 4) Always keep your notes and the Instruction sheets. 5) Enter your Kit # in the upper right corners of ALL RESULTS sheets. BILL OF MATERIALS Radio Shack Electronic Learning Lab Console, AC Adapter (9 volts at 150 ma), Digital Multimeter, Wire Stripper, Miscellaneous Connecting leads and wires (Standard for all labs) (1) Green LED (1) 1N4007 Rectifier Diode (1) 2N5551 NPN Silicon Transistor (1) 7805 IC Voltage Regulator (1) 10Kohm, ½ Watt Resistor with color code: brown black orange gold (10KΩ at 5%) (1) 1000 Ohm, ½ Watt Resistors with color code: brown black red gold (1KΩ at 5%) (1) 1µF Electrolytic Capacitor Wiring a 5 Volt Voltage Regulator Circuit Using the MC7805 (LM340) Re-read page 70 in Electronics Workbook 1 on the 7805 Voltage Regulator NOTE: In general, we will not specify every Spring # or breadboard point but it is helpful with the voltage regulator to reduce the chance of blowing everything out <grin>. Observe our wiring color code for circuit troubleshooting: red = positive supply voltage (regulated or unregulated) yellow = signals and all other wiring black = ground Figure Voltage Regulator (TO-220 Case) 4.a) Your AC Adapter connector should be connected to the back of the Console. Be sure that the Power Switch is OFF whenever you are wiring your circuits! NOTE: The +5 volt regulator circuit will NOT be removed until the end of the semester! Therefore you can cut component leads as needed to fit the circuit into a small area 4.b) Insert the 7805 voltage regulator into Breadboard holes A1, B1, C1 with the lettering 7805 facing to the right and with the metal heat sink of the device facing to the left. 4.c) Use a black wire to connect B4 (the 7805 center lead is B1) to ground 4. Put a bare wire loop from ground 3 to ground 5 for connecting to ground with meter leads, etc. 4.d) Connect a red wire from one of the top left five +V connections (e.g., +2) to C2 to connect the AC adapter unregulated +voltage (+9 to 17 V) to the 7805 IN lead at C1. 4.d) Connect a 1 µf electrolytic capacitor with its negative lead connected to B3 and its positive lead connected to A2 (prevents unwanted oscillations) Charles Rubenstein. Revision This file is available electronically at:

22 Electronics Hands-on Lab Module 04 MSCI 222C 4.e) Create an ON indicator for the +5 regulated voltage by connecting a 1KΩ resistor between A5 (the regulator output lead) and T5. Then connect a Green LED between T2 (the resistor) and ground 2 to complete the circuit of Figure 4.2. Test the circuit to see if the LED turns ON when the Power switch is moved UP. If the LED it does not light, check your wiring, and then call the instructor. 2 Figure Voltage Regulator Circuit ABOUT THE 7805 REGULATOR CIRCUIT This is a functional voltage regulator. In the text you note the addition of an electrolytic capacitor at the circuit s input to filter or remove unwanted stray AC voltages from the regulator to make it better resemble a battery voltage output. Most designs also suggest the need for a 10 µf electrolytic capacitor from the input to ground, but as we know our AC Adapter already has a 1000 µf or greater capacitor in its output circuit, thus this additional capacitor is not required. 4.f) Connect pin A4 to +6 (the 6 th voltage connection at the top of the Console Breadboard). Voltage connections +6 through +30 across the top are shorted together internally. You should put a bare wire loop between voltage connections 10 and 11 to permit easy checking of the now regulated +5 Volt supply. DO NOT REMOVE THIS REGULATOR CIRCUIT FROM CONSOLE! It will be used throughout the rest of the semester Measuring the Unregulated and Regulated Power Supply Voltages 4.1a) The unregulated, unloaded supply voltage (expect 9 17 volts DC) V. 4.1b) The regulated supply voltage (expect 4.8 to 5.2 volts; i.e., approximately 5.0 volts) V. Measuring the Relay Coil Resistance 4.2a) Turn OFF console power. Use your Multimeter, on the 200 Ohms range (green lower left) to measure the coil resistance of the relay on the Console between Spring #57 and Spring #58. The Relay Coil resistance is ohms This is Instructor check point 4A 2018 Charles Rubenstein. Revision This file is available electronically at:

23 Electronics Hands-on Lab Module 04 MSCI 222C Figure Voltage Regulator and Transistor Switch Circuit Measuring the Transistor Switch Input and Output Voltages 4.3) The 10Kohm pot, R1, and the 2N5551 NPN transistor Q1 are still connected as you had wired them in Module 3. Remove the 1K resistor and LED from the collector of the transistor in that circuit, replace the 100K resistor with R2 = 10Kohm, and add a 1N4007 diode, the relay and the buzzer, to complete Figure 4.3, above. Note: Keep the voltage regulator assembled on the Console to use its +5 Volt output for the remainder of the semester. 4.3a) Adjust the 10Kohm pot to find the lowest relay coil voltage VrelayON (measured between Spring #57 and Spring #58) which causes the relay to close - sounding the buzzer. VrelayON = volts to close the relay and operate the buzzer 4.3b) Now measure the 10Kohm pot voltage VpotON between Spring #38 to Spring #39. VpotON = volts from the potentiometer that turns on the buzzer (Note that a high current DC or AC device even a 120volt AC motor could be operated by the relay even if the motor current is well beyond the transistor s voltage rating.) Measuring the Transistor Release Voltages 4.4) Once the relay closes, the relay voltage must be lowered below the VrelayON value above to cause the relay to reset and for the switch to re-open. 4.4a) Find VrelayOFF the voltage at which the relay opens and buzzer goes off. VrelayOFF = volts to open the relay (equals relay dropout voltage) 4.4b) Find VpotOFF the voltage at the pot which corresponds to this turn off voltage. VpotOFF = volts gives the above result (equals pot dropout voltage) This is instructor check point 5B. BEFORE you break the transistor switching circuit apart, please have your instructor review your setup and the last data set of measurements Charles Rubenstein. Revision This file is available electronically at:

24 Electronics Hands-on Lab Module 04 MSCI 222C NOTES ON THE TRANSISTOR SWITCHING CIRCUIT: About the RELAY The relay is hidden under the panel. Note from the schematic drawing of the relay that the moveable arm, connected to Spring #55 (COM), will be pulled toward the contact connected to Spring #54 (NO = Normally Open) when the electromagnet is activated disconnecting Spring #55 (COM) from Spring #56 (NC = Normally Closed). Note that the inductance of the relay coil will try to keep current constant when you turn off the transistor. This inductance can RAISE the collector voltage even higher than the supply voltage. About the Diode Note how the diode will limit the collector voltage to no more than 0.6V above the supply instead of possibly over 100 volts. Note the direction of the 1N4007 diode. The cathode as indicated by the silver band on a black plastic encased device (or a black band on a glass encased device) goes to the +5V supply. About the Transistor Switch Use a 2N5551 NPN transistor as we did in Module 3 with flat side of transistor facing right and inserted into breadboard holes yielding Collector R30, Base S30 and Emitter T30. About the 7805 Voltage Regulator The 7805 voltage regulator circuit will be useful in stabilizing ANY DC input voltage between 7.5 and 35 volts to give a power supply output level of +5 volts (+/-0.2 volts) at up to one ampere of current when the TO-220 case is properly connected to a heat sink. This is convenient for analog circuits, but critical for digital circuits Therefore: Unregulated Power (VUNREG) is only available from the first five connections (+1, , +4, and +5) at the top left of the Console Breadboard. The remaining 25 connection points (+6 through +30) are internally connected and, after constructing the 7805 IC regulator circuit, provide a source of regulated +5 Volts 4 Keep this circuit wired to provide +5 volt regulated power through the end of the course! 2018 Charles Rubenstein. Revision This file is available electronically at:

25 Electronics Hands-on Lab Module 04 MSCI 222C LM7805 IC +5 Volt Regulator Circuit 5 Transistor Switching Circuit 2018 Charles Rubenstein. Revision This file is available electronically at:

26 Electronics Hands-On Lab Module 05 MSCI 222C HANDS-ON LAB INSTRUCTION SHEET MODULE 5 ANALOG IC VOLTAGE COMPARATOR NOTES: 1) To conserve the life of the Multimeter s 9 volt battery, be sure to turn the meter off if not in use for over 5 minutes. Always double check the unit is off when finishing your work, or leaving the classroom. 2) All work is to be done individually and submitted when you have it reviewed by Instructor 3) If you did not finish Hands-on Module 4, be sure to finish it NOW! before starting Module 5. 4) Always keep the Instruction sheets. 5) Enter your Kit # in the upper right corners of ALL RESULTS sheets. Keep the 5 volt Voltage Regulator (7805 with capacitor, LED) wired until end of course! BILL OF MATERIALS Radio Shack Electronic Learning Lab Console, AC Adapter (9 volts at 150 ma), Digital Multimeter, Wire Stripper, Miscellaneous Connecting leads and wires (Standard for all labs) (1) Red LED and (1) Green LED (1) TLC272 Dual Integrated Circuit Operational Amplifier (2) 1000 Ohm, ½ Watt Resistors with color code: brown black red gold (1KΩ at 5%) (2) 10Kohm, ½ Watt Resistors with color code: brown black orange gold (10KΩ at 5%) Using a TLC272 Op-Amp as a voltage comparator In this application two voltages are compared, and the output of the operational amplifier goes fully low or fully high to indicate the result of the comparison. Very little difference in voltage is needed to allow the op-amp to make its decision. 5) TEST to see if your +5 Volt Voltage Regulator Circuit is still working: 5.1) Verify: The Green LED goes ON when Power switch moved UP. ( YES, NO) 5.2) Verify: The regulated voltage output is close to +5.0 volts. ( YES, NO) ALWAYS Turn the Power switch OFF while wiring your circuits. 5.3) With power OFF initially wire the circuit of Workbook I, page 80 using one of the op amps inside a type TLC272 dual op-amp integrated circuit (IC): Figure 5.1. Comparator Circuit (Original Circuit Diagram Mims Workbook #1 - Page 80) Charles Rubenstein. Revision This file is available electronically at:

27 Electronics Hands-On Lab Module 05 MSCI 222C 5.4a) Wire the circuit of Figure 5.1 such that the TLC272 Dual Op-Amp IC is inserted with pin 1 in connection J15 and pin 8 in J16, with the RED LED across H12 and J12, and the GREEN LED across T12 and ground. The resistors should be inserted appropriately to complete the circuit. Instead of a Probe Wire we will use a potentiometer as described in step 5.4c, below. Required Circuit Modifications: 5.4b) Instead of +9V use the output of your +5V regulated power supply. 5.4c) Instead of a Probe Wire going nowhere, connect pin 3 of the TLC272 IC to the slider (Spring #38) of the 10Kohm pot. 5.4d) Connect the bottom of the 10Kohm pot (Spring #39) to ground and the top (Spring #37) to +5V so that the slider can be set for any voltage from zero to +5V. 5.4e) REDRAW THE MODIFIED CIRCUIT ON YOUR RESULTS PAGE 5.5) With power ON, measure the voltage from pin 2 of the TLC272 IC to ground. Is it close to 2.5 V as you would expect? ( YES, NO)? 5.6) Measure the pot-slider voltage at Spring #38 (with respect to ground) as you adjust the pot and observe the LEDS. 5.6a) Range of voltage that yields GREEN LED ON to volts 5.6b) Range of voltage that yields RED LED ON to volts You should observe that almost any voltage will fully light one or the other LED, with essentially no in-between range that will give both ON or neither ON. This is instructor checkpoint 5M Demonstrate that circuit works or ask for help - be clear what you are requesting Note carefully how the IC pins are numbered - looking down on the IC with pins facing down - the top view (we have removed the part number as the pin numbering is the same for all 8-pin ICs: Normally a notch shows the end on which the 1 pin is located. Occasionally there is a dot, depression, or other indication at pin 1 If the IC has dot marks on both ends, one of the marks is likely a circular trademark Charles Rubenstein. Revision This file is available electronically at:

28 Electronics Hands-on Lab Module 06 MSCI 222C HANDS-ON LAB INSTRUCTION SHEET MODULE 6 BASIC DIGITAL LOGIC NOTES: 1) To conserve the life of the Multimeter s 9 volt battery, be sure to turn the meter off if not in use for over 5 minutes. Always double check that the unit is off when finishing your work, or leaving the classroom. All work is to be done individually and submitted before you leave. Always keep the Instruction sheets. 2) Be sure you still have +5V regulated power properly wired on your Radio Shack Learning Lab Console. Keep the 5 volt Voltage Regulator (7805 with capacitor, resistor and LED) wired till end of course! BILL OF MATERIALS (1) Red LED or Green LED (1) CD4001 Quad 2-Input NOR Gate 14-pin DIP Integrated Circuit (1) CD4011 Quad 2-Input NAND Gate 14-pin DIP Integrated Circuit (1) 1000 Ohm, ½ Watt Resistor with color code: brown black red gold (1KΩ at 5%) (2) 10Kohm, ½ Watt Resistors with color code: brown black orange gold (10KΩ at 5%) (2) Single Pole Single Throw (SPST) push button switches S1, S2 (on Console) SERIES SWITCH AND GATES 1. Wire the switch and LED circuit of Figure 6.1 (similar to Workbook #2 pg.14 but using our regulated +5 volt source) from the schematic placing resistor R1 and the LED anywhere convenient. 1 Figure 6.1. Series Switch AND Logic 2018 Charles Rubenstein. Revision : This file is available electronically at: Rubenstein.com/222/06Lab.pdf Table 6.1. AND Logic Truth Table Demonstrate that switch S1 AND switch S2 must be depressed to get a high output and light the LED by filling in Table 6.1, the AND logic Truth Table noting the switch being ON or OFF and the resulting ON/OFF state of the LED. PARALLEL SWITCH OR GATES 2. Wire the circuit of Figure 6.2 (similar to Workbook pg. 15 but using our +5 volt regulated power supply.) Wire directly from the schematic: Figure 6.2. Parallel Switch OR Logic AND Logic Truth Table S1 S2 LED OFF OFF OFF ON ON OFF ON ON OR Logic Truth Table S1 S2 LED OFF OFF OFF ON ON OFF ON ON Table 6.2. OR Logic Truth Table Demonstrate that switch S1 OR switch S2 must be depressed to get a high output and light the LED by filling in Table 6.2 s OR logic truth table noting the switch being ON or OFF and the resulting ON/OFF state of the LED. This is Instructor Checkpoint 6A.

29 Electronics Hands-on Lab Module 06 MSCI 222C CD4011 QUAD 2-INPUT NAND GATE IC 3. Wire the circuit of Figure 6.4 (similar to Workbook 2 pg. 34 but using +5 volts). Insert the CD pin DIP (dual in-line package) integrated circuit across Slot 2 with its pin 1 at H10. It is best (for fastest learning) to wire directly from the schematic rather than using the Workbook suggested wiring. The pin connections are as shown in Figure 6.3. NAND Logic Truth Table S1 S2 LED Figure pin DIP Package Figure 6.4. IC NAND Gate Logic Table 6.3. NAND Logic Truth Table Be sure to follow our color code (red = + supply, black = ground, and yellow for every other connection). The CD4011 is a Quad, 2-input NAND gate which means there are four devices with logic outputs of AND followed by NOT (or inverter). Fill in Table 6.3, a truth table with a column for each input and one for the output, using 0 s and 1 s where 0 = LO (zero volts, LO = LED OFF); 1 = HI (+5 volts, HI = LED ON) This is Instructor Checkpoint 6B. CD4001 QUAD 2-INPUT NOR GATE IC 4. Leaving the overall circuit of Figure 6.3 in place: 4.1 TURN OFF THE POWER. REPLACE the CD4011 NAND gate IC with a CD4001 NOR gate IC. Be sure to insert the CD4001 across Slot 2 with pin 1 at H10. NOR Logic Truth Table S1 S2 LED Figure 6.5. IC NOR Gate Logic Table 6.4. NOR Logic Truth Table 4.2 Now turn the power back on and repeat all of part 3 for the NOR Gate IC. This is Instructor Checkpoint 6C Charles Rubenstein. Revision : This file is available electronically at: Rubenstein.com/222/06Lab.pdf

30 Electronics Hands-on Lab Module 07 MSCI 222C HANDS-ON INSTRUCTION SHEET MODULE 7 Notes: 1) Finish Module 6 before you start Module 7. 2) To conserve the 9V battery, be sure to turn meter off if not in use for over 5 minutes. 3) When you reach a checkpoint, be sure to demonstrate for credit. 4) Work slowly and carefully, this session there are a great number of wires to connect THERE ARE NO RESULTS SHEETS TO HAND IN FROM THIS LAB FORWARD. You MUST review your results with the instructor to obtain Lab credit. Components needed today: (1) 4001 Quad, 2-input NOR Gate, (1) 4013 Dual D flip-flop, (2) 4.7K resistors, (2) 10K resistors, (2) 1K resistors, one Red and one Green LED; with (4) SPST Switches, three of the ten LED displays, and the +5 V regulated supply on Console. Set-Reset Latch using a CD4001 Quad 2-input NOR Gate 1. Build an S-R flip-flop (a set-reset flip-flop also called an R-S flip-flop ) as shown in Workbook 2 pg. 27 (Figure 1). Use the regulated +5V as the supply. You may if you wish use console LEDS (say #4 and #7) as the indicators instead of individual LEDs (see Figure 7.2 for the spring numbers) as we will be doing so in the next circuit. Verify that: Figure 7.1. NOR Gate Set-Reset Latch Circuit 1a. Pressing S1 puts the flip-flop into one state (either LED1 or LED2 ON) where it stays or latches and 1b. Pressing S2 puts it into the other state where it also stays. Demonstrate the circuit Checkpoint 7A 1 Copyright C. Rubenstein Revision : This file is available electronically at:

31 Electronics Hands-on Lab Module 07 MSCI 222C CD4013 Dual Flip-flop Circuit 2. Read Workbook2 page Dual Flip-flop: Build and Understand a Data (D) Flip-flop. The CD4013 dual flip-flop is a clocked flip-flop which also has direct SET and direct RESET (unclocked) inputs. The data input is clocked, that is, it is not looked at by the flip-flop unless there is a clock pulse. NOTE: You could also wire the circuit of page 68 exactly as shown in the workbook. With power OFF: Wire the revised circuit, Figure 7.2 as shown using switch S4 to provide the data input, etc. The S4 Data input is low when released (0 volts corresponding to logic 0), or high when pushed (+5 volts corresponding to logic 1). 2 Figure 7.2. Type D Data Flip-flop Circuit With the circuit wired, your switch layout should be: S1=clock (press briefly to provide clock pulse) S2=set (direct) S3=reset (direct) S4=data Turn power on. You should see that either LED 4 or LED7 will be lit (i.e., either pin 1 high (Q=1) or pin 2 ( not Q = 1) will be high). Verify the circuit s performance as follows: a) when you briefly press S2= set, does Q go high and stay high? b) When you briefly press S3= reset, does Q go low and stay low? (try a & b a few times) c) When you leave S4= data unpressed (zero) and briefly hit S1= clock, does Q go low (or stay low) and then remain low? d) When you hold in S4= data (high) and briefly press S1= clock does Q go high (or stay high) and then remain high? (repeat c & d a few times) If all above works (= answers were YES) demonstrate the circuit: Checkpoint 7B Copyright C. Rubenstein Revision : This file is available electronically at:

32 Electronics Hands-on Lab Module 08 MSCI 222C HANDS-ON INSTRUCTION SHEET MODULE 8 The Decade Counter and One-Shot Switch De-bouncer Notes: a) Be sure to finish module 7 before starting this module. If you have finished Module 7 and are ready to DEMONSTRATE it, you may do so during the first 15 minutes of hands-on work. b) When you reach a checkpoint, be sure to demonstrate it for Lab Module credit. There are no RESULTS pages for remaining Modules. CD4017 Decade Counter The CD4017 Decade Counter IC has ten individual counter outputs that can be used. The ten states of the counter can be labeled 1-10 (as shown on Workbook 2 page 76) but we usually label these 0-9 to indicate the count (this is the preferred numbering which we use and is shown in Figure 8.1). When reset, and no pulses have come in, the state of the 4017 will be state 0 and the highest state will be state 9 after 9 pulses have come in. The 10 th pulse will reset the counter just as the reset line would. 1. With Console power OFF, connect the console LED ground springs #11, #13, #15, #17, #19, #21, #23, #25, #27, and #29 together with one bare wire. Then connect one black wire to ground. 2. Wire the circuit of Workbook 2 page 76 (Figure 8.1, below) placing the CD4017 across slot 5 with pin 1 at F25 - wire directly from the schematic diagram on the next page. (You may still have buttons S1, S2, S3, and S4 wired to +5V (all 4 lower springs) and through individual 4.7K or 10K resistors to ground (upper springs), but we will only use buttons S1 and S2 in today s lab.) 1 Figure 8.1. CD4017 Decade Counter Circuit The Numbers on the OUTSIDE of the IC symbol are the Pin Numbers Copyright C. Rubenstein Revision This file is available electronically at:

33 Electronics Hands-on Lab Module 08 MSCI 222C 3. Demonstrate that button S1 usually advances the count one step per press, but sometimes the switch contacts bounce and advance the count 2 or more steps. 4. Also verify that S2, the reset button, resets the counter regardless of the present count. Note that if S2 bounces it makes no difference because one or two or three reset pulses just resets the counter so there is no difference in result to observe. This is Instructor Checkpoint 8A. Leave the Figure 8.1 CD4017 Decade Counter set up after demonstrating it. CD4013 ONE SHOT Switch De-Bouncer The remedy for a bouncing pushbutton is a circuit that takes one or more pulses close together and generates a single pulse. This module s notes reviewed how the debounce circuit works to slow the output of the switching circuit to provide a single output pulse into the counter. 5. With Console power OFF, wire the circuit of Figure 8.2 below inserting the CD4013 across any free slot near the CD4017 with pin 1 at the upper left. Keep the debounce circuit wired for future labs 2 Figure 8.2. CD4013 One-Shot Flip-flop Switch Debounce Circuit With a time constant of R4C4 = 1 second (R4 = 100K and C4 = 10µF) demonstrate that the LED goes dark briefly each time S1 is pressed. Leave the Figure 8.2 CD4013 Debouncer set up after demonstrating it. Combining the One-shot and Decade Counter Circuits 6. With Console power OFF, connect the output of the CD4013 one-shot (pin 1) to the input of the CD4017 counter (pin 14). (Note: CD4013 s pin 1 is connected to S1 s resistor R1 to ground, and the switch itself.) Turn Console power ON and verify that S1 reliably advances the count exactly once per press. This is Instructor Checkpoint 8B. DEMONSTRATE the Debounced Input to the Decade Counter Copyright C. Rubenstein Revision This file is available electronically at:

34 Electronics Hands-on Lab Module 08 MSCI 222C Count to 5 and HOLD Circuit 7. With Console power OFF, remove the ground wire on pin 13, CLOCK ENABLE CE. Restore Power and try various connections of CE going to output states 0 through 9. Based on these results, wire the CE such that the count, after resetting to 0 pressing S1 results in counting: 1, 2, 3, 4, 5, 5, 5 (i.e., does not advance beyond 5). This is Instructor Checkpoint 8C. Demonstrate the COUNT TO 5 and HOLD CIRCUIT Divide by N Circuit 8. With Console power OFF, remove the wire from pin 13, CLOCK ENABLE CE going to any of the output pins from the last experiment and reconnect it to ground. 9. Remove the ground wire on the RESET pin (pin 15) and transform your circuit into a Divide by 5 counter by connecting the RESET to Output State 5 (CD4017 pin 1). Confirm this condition by turning on the power and testing the circuit. This is Instructor Checkpoint 8D. Demonstrate the DIVIDE BY 5 CIRCUIT Show that after reset to 0, the 5 th incoming pulse will cause a reset. (Note that the reset line goes high after the 5 th pulse briefly - and could signal another circuit that 5 pulses had come in - but that brief a pulse might not reliably trigger the next circuit unless some additional circuit e.g., another flip-flop is used.) 3 Copyright C. Rubenstein Revision This file is available electronically at:

35 Electronics Hands-on Lab Module 09 MSCI 222C HANDS-ON LAB INSTRUCTION SHEET MODULE 9 SHIFT REGISTER NOTES: Make sure you have the following still wired: a) The 7805 Voltage Regulator b) All ten upper springs on the console LEDS grounded. c) All 4 lower springs on the push buttons going to +5V. d) The S1 push button de-bouncer using a D Flip-Flop from Module 8. You will need to use the second CD4013 IC from your kit today. Three Stage Shift Registers Read Workbook 2 page 74 on the construction of a 2-Stage Shift Register carefully. Do NOT wire that circuit. Instead of a de-bounced input as we had been using, the Workbook circuit uses an oscillator (or free-running pulse source) constructed out of two inverters and two stages. We will use three stages to make it easier to see the movement of data through the circuit and de-bounced button presses of S1 to clock all the flip-flops to see the state changes. We are using two CD4013 Dual D Flip-Flops in this circuit. You already have half of the first CD4013 IC wired as a one-shot to de-bounce S1. We ll call this output QA. The other half of this CD4013 IC and the second CD4013 IC will provide for an additional three, type-d Flip-Flops which we will use as the shift register outputs: Q1, Q2 and Q3. (Note that each CD4013 IC contains 2 D Flip-Flops. Each pair of devices shares pin 7 as ground and pin 14 as Vcc or +5V.) 1. Turn Console power OFF and wire the circuit of Figure 9.1 on the next page. Although we have renumbered the R4 and C4 time constant determining components from Lab Module 8 as R1 and C1 we will continue to use R1=100K ohms and C1=10uf for an R1C1 de-bounce circuit time constant of 1 second for the CD4013 debouncer circuit for S1. Using the de-bounced S1 push button to provide individual clock pulses, verify the following: A) When DATA button S2 is not pressed (data input low), verify that repeated clock pulses (using S1) give a 000 output from the Shift Register. B) With DATA button S2 held in (data input high), verify that the Shift Register output is: 100, then 110, and then 111. C) Verify that by entering appropriate data pulses you can get a 101 output. Checkpoint M9 Demonstrate A, B, and C above. 1 Copyright C. Rubenstein Revision This file is available electronically at: :

36 Electronics Hands-on Lab Module 09 MSCI 222C Figure 9.1 Two CD4013 Dual D Flip-flops used to create One Debouncer and a three Stage Type-D Flip-Flop Shift Register 2 Copyright C. Rubenstein Revision This file is available electronically at: :

37 Electronics Hands-on Lab Module 10 MSCI 222C HANDS-ON LAB INSTRUCTION SHEET MODULE 10 The NE555 IC Timer The NE555 IC Timer (Analog/Digital Circuit) The 555 IC is a multi-purpose integrated circuit that contains both analog and digital circuits: Analog Portion: two comparators and a BJT transistor with open collector output (There is also a low-power CMOS version of the 555 using FETs.) Digital Portion: a Set-Reset Flip-Flop with a 200 ma output stage. The NE555 is most often used as a timer or a rectangular wave output oscillator. Part A. NE555 IC Timer Re-read Workbook 2 page 37 which describes how the NE555 can be used with a CD4011 Quad NAND Gate to make a Red-Green Alternating Flasher. 1 Figure Improved NE555 Timer Circuit and 8-pin NE555 DIP layout 1. Build the circuit of Figure 10.1 which shows an improved and more versatile version of the NE555 circuit with the following improvements made to the original circuit: a) The 555 can sink or source up to 200 ma (i.e., up to 200 ma in or out of pin 3). b) R1 - the 1 Megohm (1 MΩ) pot - is connected as a variable resistor with the slider connected to the bottom. This is a best practice for using a variable resistor so that if the slider contact briefly lifts off the resistive material, as may be the case with a BAD potentiometer, the device s resistance jumps to 1 MΩ rather than to infinity resistance. This change also results in a smoother operation (e.g., less noise in an audio system). Copyright C. Rubenstein Revision This file is available electronically at:

38 Electronics Hands-on Lab Module 10 MSCI 222C c) C1 (the timing capacitor) can be either 1 µf or 4.7 µf, etc. d) The RA - the 1 KΩ resistor R3 between +5V and pin 7 - should be a lower value than RB the resistance between pins 6 and 7 here the two resistors R1 (up to 1 MΩ) and R2 (1 KΩ) - in order to have the on times of the two LEDs close to equal. In reference texts, this issue is discussed as the pulse generator s duty cycle. Duty Cycle Calculations It can be shown that τ1= (RA + RB) C1: C1 charges through (RA + RB). and τ 2= 0.693(RB C1): C1 discharges into the BJT collector at pin 7 through RB only. To make τ 1 and τ 2 nearly equal, RA should be kept small with respect to RB. 2. A loudspeaker has been added to allow listening to the output as well as seeing the Green LED flashing. LED current limiting resistors R4 and R5 are 100 ohms instead of 1KΩ for brighter LEDs and louder speaker output. This is permitted because of the high current output capability of the NE555 as compared to CMOS digital logic gates. This is Instructor Checkpoint 10A. Demonstrate that adjusting the 1 MegΩ pot changes the frequency of the flashing LEDS as well as the audio output. Light Control of NE555 Oscillators using Photoresistors Read Workbook2 page 52, bottom for information on the photoresistor.. 3. Turn Console power OFF, and remove the current RB components (R1, the 1 MΩ pot, and R2 the 1KΩ resistor) between pins 6 and 7 of the NE555 in your circuit. Do NOT remove any other components or connections. 4. Connect the Lab Console s photoresistor as RB by connecting NE555 pin 7 to spring #64 and NE555 pin 6 to spring #65. The photoresistor s schematic symbol and typical wiring are shown as Figure Note that the resistance of this particular photoresistor decreases as a function of light falling on it. (You might want to check its light-dark resistance range with the Ohmmeter.) Figure Wiring the Photoresistor into the Circuit This is Instructor Checkpoint 10B. Demonstrate the effect light levels have on LED flashing and audio output. 2 Copyright C. Rubenstein Revision This file is available electronically at: