PAD - 234 ANALOG / DIGITAL TRAINER
OPERATOR’S MANUAL
Rev. 7/94
1
GENERAL OPERATING PROCEDURES
1. This manual should be read thoroughly before engaging in anyexperimentation. 2. As a general rule, NEVER construct a circuit orinsert any wiring with the PAD unit ON. 3. Construct the circuit.Double check your wiring. Then apply power to the circuit. 4.Should a problem occur. Turn the unit off immediately. Unplug thePAD and notify your instructor. 5. In the event this unit needsrepairs, notify your instructor.
DO NOT ATTEMPT TO REPAIR THIS UNIT YOURSELF​!!

MAINTENANCE OF THE PAD 234 ANALOG DIGITAL TRAINER
* * * CAUTION * * *
FUSE REPLACEMENT 1. Before replacing the fuse be sure that thepower switch is in the off position and unplug the pad !! 2. Useonly MDL 0.5 amp fuses. 3. Unscrew the black cap on the right sidepanel of the PAD unit and remove bad fuse. Replace with the correctfuse in the same manner.
******* WARNING *******
Do not use all sources simultaneously !! keep liquids away from thePAD unit !! Do not use near flammable materials !!!

PAD 234 ANALOG DIGITAL TRAINER
POWER SUPPLY – (+) and (–) 12 volt regulated power supply, with 500ma short circuit protection. – (+) 5 volt regulated power supply,with 1 amp short circuit protection. – (+) and (–) 15 volt variablesupply (from 1.5 V to 15V) with 1.5 amp short circuit protection. –(+)12.6 Volt AC center tap power supply.
FUNCTION GENERATOR – Sine, square, and triangle output wave shape.1 Hz to 100 Khz in 5 ranges, uncalibrated, buffered, adjustableoutput 0 to 15 volts peak to peak.
CLOCK OUTPUT (TTL) – Frequency determined by COARSE FREQUENCY FINEFREQUENCY adjustment knob. Rise and fall time is 400 ns.
INDICATORS – 8 BUFFERED TTL compatible LED'S.
SWITCHES – 8 binary toggle switches (0 or 5 Volts) 2 momentarypulse switches, debounced with complimentary outputs
BREADBOARDS – 2 breadboards with 840 plug-in tie points each.
POWER CONSUMPTION – 117 Volts at .5 Amps
ADDITIONAL FEATURES – High impact plastic case with a 3-wiregrounded line cord. Fuse protected AC line.

OPERATION
DC POWER SUPPLY – +5, +12, –12, located in the vertical row ofbinding posts, positioned along the left side of thebreadboards.
Use of 5V Supply – Connect the load between the binding post andthe GND (ground).
Use of + 12V – Connector the load between the Binding Post marked +12V and the Binding Post marked GND (ground).
Use of –12V – Connect the load between the Binding Post marked –12V and the Binding Post marked GND (ground) .
VARIABLE DC SUPPLY – Located above left to the main breadboards andidentified as + 15V, controlled by the appropriate knobs. (Lowerleft hand corner of the top plate.)
Using the + 15V – Connect the load between the tie blocksidentified as + 15 V and OV (ground). Use the knob marked + 15V tocontrol the output voltage of this tie block.
Using the –15V – Connect the load between the tie block identifiedas – 15V and OV (ground). Use the knob marked – 15V to control theoutput voltage of this tie block.
AC POWER SUPPLY – Located above right to the main breadboards andidentified as AC Volts.
Using the 6.3 VAC – Connect the load between the tie blockidentified as 6.3 and 0 (ground).
Using the 12.6 VAC – Connect the load between the tie blocks marked6.3 and 6.3.
FUNCTION GENERATOR – The output for the GENERATOR and CLOCK areIocated in the top two Binding posts in the vertical row, on theleft hand side of the breadboards marked GEN and CLOCK. – Thegenerator and clock outputs are controlled by the five knobslocated on the far left hand side of the PAD unit and markedaccordingly

GENERATOR (CONTINUED) Before using the Generator or Clock outputin an actual circuit, familiarize yourself with the functions ofthe five control knobs and the effects they have on the outputwaveforms. Connect an oscilloscope to the GEN Binding post and GNDBinding post as described above. Adjust the O-scope as necessary toobserve a clearly visible waveform. By using the five control knobsobserve how you are able to adjust the output waveforms, by usingthese controls. (See the section below labeled \"Using theGenerator\".
Using the CLOCK – Connect the load between the Binding posts .marked CLOCK and GND (ground). – Select the appropriate frequencyusing the knob marked COARSE FREQUENCY. – Adjust to the exactfrequency using the knob marked FINE FREQUENCY.
Using the GENERATOR – Connect the load between the Binding Postsmarked GEN (Function Generator) and GND (ground) .
1. Select the type of waveform required by using the top left knob.2. Set the COARSE FREQUENCY knob to the correct range. 3. Fine tunethe frequency (using the knob marked FINE FREQUENCY) to the exactfrequency required. 4. Adjust the amplitude (using the AMPLITUDES)knob to adjust the output voltage maintaining a clear waveform. 5.Adjust the offset as needed with the bottom control knob markedOFFSET.

DIGITAL SECTION – Located across the top of the PAD – Thissection includes eight manual toggle switches, eight LED tie blocksand two pulse switches.
Using the Toggles – Connect the device between the tie block to beused (numbered 0 to 7) and GND (ground) . – When the toggle switchis in the up position, +5 volts is supplied to the device. When theswitch is in the down position 0 volts is applied.
Using the LED Tie – Connect the device to the tie block directlyunder the LED to be used. When + 5V is applied the LED will light,when 0 is applied it will be off.
Using the Momentary – For + 5V pulse connect the device to the tieblock marked O. When the switch is pulsed the output at the tieblock will be +5V. For O V pulse, connect the device to the tieblock marked 1. +5 V will be applied to the point block till theswitch is pulsed, then the output will be O V.
To become more familiar with the toggle switches and LED tiepoints, take a piece of wire and connect between one of the Toggletie point blocks and one of the LED tie point blocks. Flip theswitch and observe that voltage is being applied, lighting the LED.Repeat this procedure using the momentary pulse switches.

PAD 234 EXTENDER DESCRIPTION

A 16-pin Insulation Displacement Connector (IDC), labeled EXTENDERon the top plate of the PAD 234, allows ribbon-cable connection topersonal computers and other electronic equipment. The user cansupply power, analog, and digital signals to add-on boards via aribbon cable. The EXTENDER has eight uncommitted bidirectionallines which can be easily connected via tieblocks to the LEDs andswitches of the PAD 234. Also, add-ons or external equipment can beinterfaced to circuits already breadboarded on the trainer. Inaddition, the function generator built into the PAD 234 can beeither AM or FM modulated by applying signals to either pins 15 and16 of the IDC or tie-blocks X and Y. Since pin 15 (FM) iscapacitively coupled to the function generator, it may be used asan additional DC-level signal in certain applications.

CET/EET235 DIGITAL ELECTRONICS DESIGN Logic Gate Summary

NOTE: An Inversion Circle “ ” on a gate indicates that the LogicSignal is INVERTED when it passes through the inversion circle.(Hardware inside the gate at that point inverts the signal.)


LOGIC GATE

LOGIC SYMBOL

BOOLEAN EQUATION

TRUTH TABLE

   A B F (OUT)

Buffer



f = A

0 1

0 1

Inverter (NOT)



f = A _


0 1

1 0


AND




f = A • B

0 0 1 1

0 1 0 1

0 0 0 1



NAND



f = A • B _____


0 0 1 1

0 1 0 1

1 1 1 0



OR




f = A + B

0 0 1 1

0 1 0 1

0 1 1 1



NOR



f = A + B _____


0 0 1 1

0 1 0 1

1 0 0 0



Exclusive OR (XOR)




f = A ⊕ B

0 0 1 1

0 1 0 1

0 1 1 0



Exclusive NOR (XNOR)



f = A ⊕ B _____


0 0 1 1

0 1 0 1

1 0 0 1

CET/EET235 DIGITAL ELECTRONICS DESIGN Boolean AlgebraSummary


Boolean Algebra: is a logical algebra based on the binary systemdeveloped in the 1850s by George Boole, a mathemetician.

3 basic functions: AND (•), OR (+), NOT (_); variables; equations;hierarchy of operators

LAWS of Boolean Algebra:

1. Commutative - “order doesn't matter” AND: A • B = B • A OR: A +B = B + A

2. Associative - “grouping doesn't matter” (only applies to ≥2variables and/or constants) AND: ( A • B ) • C = A • ( B • C ) OR:( A + B ) + C = A + ( B + C )

3. Redundancy (Tautology) - simple reduction A _ _ = A A • 0 = 0 A+ 0 = A   A • 1 = A A + 1 = 1   A • A = A A + A= A   A • A _ = 0 A + A _ = 1

4. Distributive / Factoring A • B + A • C = A • ( B + C ) A + ( B •C ) = ( A + B ) • ( A + C )

5. Absorbtion a. A • ( A + B ) = A • A + A • B = A + A • B = A • 1+ A • B = A • ( 1 + B ) = A • 1 = A b. A + ( A • B ) = ( A + A ) •( A + B ) = A • ( A + B ) = … = A c. A + A _ • B = ( A +A _ ) • ( A+ B ) = 1 • ( A + B ) = A + B d. A _ + A • B = ( A _ + A ) • ( A _+ B ) = 1 • ( A _ + B ) = A _ + B


DeMorgan's Theorems:

A • B _____ = A _ + B _ ⇒ “the complement of a product = the sum ofthe complements”



A + B _____ = A _ • B _ ⇒ “the complement of a sum = the product ofthe complements”

CET/EET235 DIGITAL ELECTRONICS DESIGN Units Reference


Factor Number Prefix Symbol Example 1018 quintillion Exa E Eb -exabyte 1015 quadrillion Peta P Pb - petabyte 1012 trillion Tera TTb - terabyte 109 billion Giga G Gb - gigabyte 106 million Mega MMhz - megahertz 103 thousand Kilo k kΩ - kilo ohm 100 -  10 -3 thousandth Milli m mH - millihenry 10 -6 millionth Micro µ µF- microfarad 10 -9 billionth Nano n ns - nanosecond 10 -12trillionth Pico p pF - picofarad 10 -15 quadrillionth Femto f fs -femtosecond 10 -18 quintillionth Atto a ab - attoboy!?!

Table 1: Engineering powers of 10



Color Digit Value Multiplier Value
Toleranc e Value Black 0 10 0 - Brown 1 10 1 - Red 2 10 2 - Orange3 10 3 - Yellow 4 10 4 - Green 5 10 5 - Blue 6 10 6 - Violet 7 10 7- Gray 8 10 8 - White 9 10 9 - Gold - 10 -1 ±5% Silver - 10 -2 ±10%(none) - - ±20%



Table 2: Resistor Color Code

CET/EET235 DIGITAL ELECTRONICS DESIGN Parts Kit InventoryList


Qty.Description                                             Labs Used

I.C.s:   1 4001 CMOS Hex Inverter 11   1 4009CMOS Quad NOR Gate 11   1 7404 TTL Hex Inverter10   2 74LS00 Quad NAND Gate 4,15,16,18   174LS02 Quad NOR Gate 4,15   1 74LS04 Hex Inverter2,3,5,7,9,16,20   1 74LS08 Quad AND Gate3,5,7,8,9,19   1 74LS14 Hex Schmitt Inverter22   1 74LS32 Quad OR Gate 3,7,8   1 74LS42BCD-to-Decimal Decoder 12   1 74LS47 BCD-to-7-SegmentDecoder 14   1 74LS74 Dual D Flip-Flop 16,17  1 74LS75 4-bit Latch 16   2 74LS76 Dual J-K Flip-Flop17,18,19,20   1 74LS83 4-bit Adder 9   1 74LS86Quad XOR Gate 4,5,8,9   2 74LS90 BCD Counter19   2 74LS93 4-bit Binary Counter 19   174LS95 4-bit Shift Register 21   1 74LS150 Multiplexer13

Resistors:   1 47Ω ¼W Resistor (yel-vio-blk)14   1 56Ω ¼W Resistor (grn-blu-blk) 10   1330Ωx8 16 pin DIP Resistor Array 14   1 1kΩ Potentiometer10,22   2 4.7kΩ ¼W Resistor (yel-vio-red) 15  1 5kΩ Potentiometer 14

Capacitors:   1 0.01µF Ceramic Disc Capacitor22   1 0.68µF Mylar Capacitor 22

Miscellaneous:   1 Red T-1¾ LED 14   17-segment C.A. Display 14   1 SPDT Toggle Switch 15



Custom Prepackaged Parts Kit Available From:

R.S.R. Electronics, Inc. 1560 Hart St. Rahway, NJ 07065 Ph:908-381-8777 FAX: 908-381-1572

CET/EET235 DIGITAL ELECTRONICS DESIGN Experiment TroubleshootingGuide


The following is a list of some common problems encountered duringlab experiments. For each problem listed, a suggested solution isgiven.

• Wrong chip used.  Make sure correct chip number is read fromI.C., i.e.: not the date code.

• Chip inserted upside-down.  Correctly identify pin 1 and orientchip so pin 1 is to the lower left.

• Chip plugged in incorrectly.  Make sure chip straddles one ofthe open channels in the breadboard. Also make sure all pins arepresent, straight and fully seated in a breadboard hole. Bent orbroken off legs can quickly cripple an I.C.

• Wrong pinout used.  Double check your I.C. pinout charts to besure correct chip is being used.

• No power to I.C.  Ensure both Vcc and Ground are connected tothe trainer power supply, including connections through breadboardhorizontal busses. Some CMOS I.C.s additionally require a Vddconnection.

• Short between Vcc and Ground.  This problem is easily identifiedby observing the logic probe while not connected to any part of thecircuit. The light should be dim, indicating a floating input. Ifthe logic probe doesn't light at all, a short between Vcc andGround exists. Immediately remove power and thoroughly check allpower busses on the breadboard to correct the error.

• Wrong pin count.  Make sure you are counting pin numberscounter-clockwise around the chip starting from pin 1, which shouldbe towards the lower left. It is also common to incorrectly countpins 1 to 7 across the bottom and 8 to 14 across the top when a 16pin chip is being used.

• Bad or broken wire.  It is possible for a wire to become brokeninside the insulation somewhere along its length, causing a brokenconnection. A quick check for this problem is to connect this wirebetween a switch and an LED and verify proper LED operation. Also,use only solid conductor wire, stranded wire does not work wellwith breadboards and should be removed from your kit and discarded.Use wires of appropriate length. Excessively long wires only makestroubleshooting more difficult. Make sure the ends of the wire arestripped to about 1/4\" and are straight. Obtain wirecutters/strippers from the instructor to correct theseproblems.

• Bad I.C.  It is possible for an I.C. to become damaged andnon-functional by abusive handling, improper wiring, etc. althoughactual occurrence of this problem is rare. The chip in questionshould be isolated in a test circuit configuration fordiagnosis.

Laboratory Hints:  Wire power pins to all I.C.s first. Thiseliminates the possibility of forgetting these connections.  Use ahighlighter to mark connections on the circuit diagram as they arebeing made.  Use the logic probe -- it is your friend. This toolcan be used to diagnose specific points in the circuit and nearlyalways finds wiring errors.

Lab 1: DIGITAL TRAINER FAMILIARIZATION Exercises
Read and perform the following exercises. If you are unsure aboutany step, please ask for assistance. It is better to ask thandamage the equipment (and possibly yourself!).
Using the Digital Trainer – Overview From this point forward inthis lab, you will make use of the Digital Trainer or NationalInstruments MultiSim to build and test Digital Logic circuits. TheDigital Trainer, shown in Figure 1, provides a simple-to-usehands–on digital interface which will allow you to more easily andrapidly construct experimental circuits from real IntegratedCircuit components.
For this lab, we will use the following features of the DigitalTrainer : +5.0V regulated power supply, attached breadboard, LEDindicators, digital logic switches, and the Clock FunctionGenerator. The Digital Trainer power supply is current and voltageregulated to prevent damage in the event of a short circuit, withno additional steps required. Also, the LED indicators do not needa ground or current-limiting resistor. These are integrated intothe Trainer. Finally, the digital logic switches output either HIGHor LOW logic voltages which you can use DIRECTLY as logic inputs toyour gates or to the LEDs.

Figure 1—Digital Trainer
Exercise 1: Equipment and Component Inventory 1. Get a DigitalTrainer unit from the equipment Cabinet. If you need additionalconnection wires, see the instructor.
2. Download the “PAD-234 Digital Trainer - Operators Manual” fromContents > Handouts. This describes all of the controls on theDigital Trainer.
CLK Frequency Generator Terminal
CLK Freq Gen Controls
+5V Circuit Power (VCC)
0V Ground (GND)
Indicator LED Inputs
Logic Switches Logic Switch Outputs
Lab 1: Digital TrainerFamiliarization      2 / 8

3. Also download “CET235 - Quick Reference - Gates, Boolean Logic,Etc.pdf” from the Handouts area. This file contains Gate functionsand other helpful information you will need during this andsubsequent labs. Save this file with your other course files andBRING it with you to labs.
4. Open the Quick Reference document and just briefly look at whatis on each page.
5. Obtain one 74LS04 Integrated Circuit (IC) (both work same forthis lab) from your Electronics Parts Kit, or from the instructorif you did not purchase a kit. If you purchased the ElectronicParts Kit from the Campus Bookstore for this course, verify thatthe kit contains all of the components listed on the “parts kitinventory list” included in the box.. Be careful not to confuseintegrated circuit ID numbers with date codes. See the instructorif any questions.
6. Open the black Digital Trainer Case. The trainer consists ofpower supplies, digital switches, LED digital indicators, and abreadboard area where you can construct IC circuits.
7. With the Trainer in front of you, read the following paragraphscarefully, at least two times. Look at the PAD-234 Digital Trainer- Operators Manual as needed for additional information or morephotos of the controls.
The breadboard is constructed with disconnected power busses ( RED+ and BLUE – ) running left to right across the whole breadboard atthe top and bottom, and IC Chip / component insertion areas betweenthe power busses.
The horizontal pins in each power buss are all connected togetherall the way across the breadboard. The Blue busses should be usedfor ground, and the Red busses should be used for +5V (VCC)power.

The IC Chip / Component insertion areas are between the busses andalso extend all the way across the breadboard. Each insertion areahas an upper set of pins (A – E), and a lower set (F – J), with asmall valley between the two groups. Each column of 5 pins abovethe valley is connected together. Each column below the valley isconnected together.   Insert ICs horizontally so the pinson one side of the IC are above the valley and the pins on theother side are below it.   Since the column of 5 pins areall connected, you can put a connection wire into any of the pinsin the column to connect that IC pin to another gate or to adevice.
8. Verify that the Trainer breadboard is empty (nothing plugged init). NOTE: If you ever notice any wires broken off in yourbreadboard, bring it to the instructor's attention -- do notattempt to remove them. Instead mention it to yourinstructor.
9. Using connecting wire, connect the Trainer’s BLACK GroundTerminal (0V, GND) to one of the Breadboard’s BLUE GNDbusses.
10. Connect the Trainer’s RED +5V Terminal (VCC) to one of theBreadboard’s RED +5V busses.
11. Plug in the digital lab trainer and turn the POWER switch ON.For each of the following trainer components, identify it andperform the related procedure.
GND 0V
VCC +5V
Lab 1: Digital TrainerFamiliarization      3 / 8

Power Supply
12. The trainer contains internal DC regulated power supply outputslocated at the left of the breadboard fixed at +5V, +12V, and –12V.Additional adjustable voltages (1.5 V to 15 V) +V and –V outputsare also available. You will only use the +5V and GND powerterminals today.
13. Verify that the POWER LEDS for +5V, +12V, –12V are ON. Informyour instructor if not all ON!
NOTE: NEVER allow any of the power supply outputs to come intocontact with each other or with ground (GND), as this may blow acircuit breaker.
LED Indicators
14. Above the breadboard on the right, are eight LEDs (LED7–LED0)which indicate the logic level of whatever they are wired to (ON =logic high, OFF = logic low). Note their numbering (MSB on LEFT,LSB on the right) and that with nothing connected, these LEDs areinternally biased to be OFF.
15. Connect a single wire from one of the LEDs first to +5V thenmove it to GND and note the results on the LED.
16. Check ALL of the LEDs in the same way to verify they areworking. If not, inform the instructor.
Logic Switches
17. To provide Logic Inputs to your circuits, the trainer has anumber of logic switch outputs across the top of the trainer. Thisincludes eight logic switches (7 thru 0). The switches produce alogic HIGH or LOW output depending on their position.
18. Reconnect the previous wire from the LED to one of the logicswitches and note the effect on the LED of each of the switch's twopositions. Switch is ON when switched UP and OFF when DOWN.
19. Two pulse switches also provide either a HIGH or LOW bydefault, then give the opposite value while pulled forward.
20. Reconnect the previous wire from LED 7 to a pulse switch “1”pin (positive logic) and note the effect on the LED as you pulsethe switch. Connect another wire from the “0” pin (negative logic)of the same pulse switch to LED 6, and observe the different outputpattern the “1” and “0” pins between the two LEDs. One is a pulsehigh, and the other is a pulse low.
21. Disconnect the LED wires.
Function Generator
22. A Function Generator on the left of the Trainer supplies timedvoltage wave outputs on the Trainer’s GEN Terminal in the form ofSine wave, Square wave, and Triangle wave at variable voltages. Youwill NOT use the GEN Terminal during this lab.
23. The Generator also supplies a timed Digital Logic output on theRed CLK (Clock) Terminal. Later in this lab we will use the Red CLK(Clock) Terminal to provide a 1 Hz logic signal to our circuit.

Lab 1: Digital TrainerFamiliarization      4 / 8

Exercise 2: INVERTER Gates Investigation 24. Power OFF thetrainer.
25. Place the TTL level HEX Inverter 74LS04 horizontally (sidewaysas shown) on the RIGHT side of the breadboard (closer to the LEDsand Switches). Position it with the case indent on the LEFT asshown. 26. Straddle the IC over one of the valleys on thebreadboard so the pins on top are above the valley, and bottom pinsare below the valley, similar to the following.
                         
The 74LS04 IC has six individual Inverter logic gates combined inone IC. The IC requires a separate +5V power supply connection anda connection to Ground. This power connection provides power to thetransistors in the IC which make up the logic gates. 27. Connectthe Trainer’s Red +5V terminal to one of the RED power busses onthe breadboard. Connect the Trainer’s Black Ground Terminal to oneof the BLUE power busses on the breadboard.
28. Using the 74LS04 pinout diagram below, connect the IC power pin14 (VCC) to the RED breadboard Buss from previous step (+5V).Connect the IC ground pin 7 (GND) to the breadboard Ground BLUEbuss from previous step.

On the Inverter gatesymbols:        ,      the straight (LEFT) side of thetriangle is the INPUT, and the small circle (RIGHT) side is theOUTPUT. Each inverter gate functions like the Transistor InverterCircuit we looked at in lecture copied below right:   AHIGH input results in a LOW output. A LOW input results in a HIGHoutput. The small “Inversion Circle” on the inverter outputindicates that the signal is INVERTED (also known as“Complemented”) as it leaves the gate.

Figure 2—7404 / 74LS04 Pinout Diagram
29. Connect the output of one of the logic switches DIRECTLY to theinput (pin 1) of the 1st Inverter (Don’t use resistors.) AND,connect pin 1 DIRECTLY to LED7 (NO resistors.) This lets you easilysee the ACTUAL input value of the gate (not through any inverters)for debugging your circuit.
30. Connect the OUTPUT (pin 2) of 1st Inverter to LED6 so you canview the inverter output.
Case Indent
BreadboardValley
Input Output
Gate 1 Gate 2 Gate 3
Gate 4 Gate 5 Gate 6
=
Inverter circuit from lecture

Case Indent
Pin 1
Pin Numbers
Lab 1: Digital TrainerFamiliarization      5 / 8

31. Turn ON the power and toggle the logic switch to change theinput to the gate back and forth between ON “1” & OFF “0”states, and fill in both rows of the Worksheet Truth Table “1Inverter Output” column based on your observations. Verify thatyour 1 Inverter Outputs are correct using the Inverter gate TruthTable in the CET235 – Quick Reference document.
32. Next, Connect the output of the first inverter to the input ofthe 2nd inverter shown below. Connect the output of the 2ndinverter to LED5. The Inverter gate input/output pin numbers areshown:

33. Toggle the switch as necessary to observe the output of thesecond inverter on LED5 based on the switch input to the 1stinverter, and fill in both rows of the 2 Inverters Output column ofthe Truth Table. This column indicates how a logic signal 0 or 1 isaffected after traveling through 2 inverter gates.
34. Connect the output of the 2nd inverter to the input of the 3rdinverter. ALSO connect the output of the 3rd inverter to LED4. Thegate pin connections are shown:

35. Toggle the switch as necessary to observe the output of thethird inverter on LED4 based on the switch input to the 1stinverter, and fill in both rows of the 3 Inverters Output column ofthe Truth Table. This column indicates how a logic signal 0 or 1 isaffected after traveling through 3 inverter gates.
36. Connect the 4th inverter in line as shown. Connect the outputof the 4th inverter to LED3 as shown:

37. Toggle the switch as necessary to observe the output of thefourth inverter on LED3 based on the switch input to the 1stinverter, and fill in both rows of the 4 Inverters Output column ofthe Truth Table. This output indicates how a signal is affectedafter traveling through 4 inverter gates.
Lab 1: Digital TrainerFamiliarization      6 / 8

38. Use the pin numbers shown below to connect the 5th inverter inseries and connect it’s output to LED2. Toggle the switch as neededto complete the 5 Inverters Column. Finally connect the 6thinverter and also connect it’s output to LED1 then complete the 6Inverters Column of the Truth Table appropriately. KEEP YOUR WIRESNEAT so you’ll have to do LLEESSSS troubleshooting!

Figure 3—Final Six INVERTER Chain Schematic
39. LED7 displays the input switch value, and LED6 through LED1allow you to see how the input signal is inverted by each inverter,one after another, as it travels through your circuit from left toright.
40. Toggle the logic switch back and forth between High and Low.Observe how the switch signal propagates through the series ofinverters. If you set the Input Switch ON, what is the output ofthe 1st inverter?   What does the 2nd inverter do to thesignal? What does the 3rd inverter do to the signal? What doesevery odd number inverter do the signal?    Everyeven numbered inverter?
41. Complete the questions on the Worksheet after InvertersConnected in Series Truth Table.
Replace Switch with Digital Clock Signal. 42. Turn the TrainerOFF.
43. IMPORTANT !!: DISCONNECT the wire from the logic switch to the1st inverter input pin, but leave all other pins connected.
44. Set the Frequency Generator Mode dial (top left) to Square Wave( ), and the COARSE FREQ dial to 1 Hz (NOT 1K Hz !) 45. Connect theTrainer’s Red CLK (Clock) Terminal to the 1st Inverter gate’s inputpin to connect the CLK’s 1 Hz oscillating clock output to theInverter gate’s input.
46. Turn the Trainer back ON. 47. You should now see the 1 Hz CLKsignal traveling all the way through the six connected inverters inthe 74LS04 as displayed on the LEDs. The CLK signal is successivelycomplemented by each inverter as it travels through each of the sixinverters.
Exercise 3: Control Gate Investigation For this exercise you willhook up an “AND” gate between the output of the CLK signal and the1st inverter input and investigate one common way for a gate tocontrol a signal. The AND gate has two inputs. The CLK signal willbe connected to one of the AND Gate’s input pins, and a SWITCH willbe connected to the other. 48. Turn the Trainer OFF.
49. Leave all of the inverter and LED pins connected. Obtain a74LS08 Quad 2–Input AND Gate IC from your parts kit or from the Labparts bins.
Inverter.

Lab 1: Digital TrainerFamiliarization      7 / 8

50. Plug the 74LS08 AND IC into the breadboard in the same mannerat the 74LS04 Inverter IC. The 74LS08 AND IC has four (Quad)individual AND logic gates combined in one IC. Each gate has twoinputs and one output. The IC also requires a separate +5V powersupply connection and a connection to Ground. The AND gate ONLYgives a logic HIGH output when BOTH inputs are set to logic HIGH,otherwise the output is LOW.
51. Using the 74LS08 pinout diagram below, connect the IC power pin14 (VCC) to the RED breadboard Buss from previous step (+5V).Connect the IC ground pin 7 (GND) to the breadboard Ground BLUEbuss from previous step.

Figure 4—74LS08 Quad 2–Input AND Gate Pinout Diagram
52. See the diagram below, and Connect the output of the Trainer’sRed CLK Terminal to Pin 1 of the 74LS08 IC (1st input of 1st ANDgate). 53. Connect the output of the SWITCH to Pin 2 of the AND IC(2nd input of 1st AND gate). 54. Connect Pin 3 of the AND IC(Output of 1st AND Gate) to Pin1 of the Inverter IC (1st Inverterinput pin).   This places the AND gate between the CLKoutput and the 1st Inverter gate.


Figure 5—AND Gate Control of CLK Signal to Inverters
55. Turn the Trainer back ON. 56. Turn the SWITCH ON, and VERIFYthat LED7 blinks at the frequency set on the Clock control. IF NOT,check and verify the connections from the CLK terminal. Also checkthe SWITCH to the AND gate inputs, and the AND gate output to the1st Inverter. ALSO CHECK the AND IC POWER +5 and GND connectionsfrom the busses to the AND IC.   See instructor for help.57. Toggle the SWITCH ON and OFF and observe what happens in eachcase to the signal propagating from the gate output to the seriesof inverters.   Answer Exercise 3 questions in theWorksheet.
Obtain Credit for the Lab. 58. Leave your circuit connected withthe oscillator running, until you Demonstrate your circuitoperation to the Instructor or Lab Assistant for Credit. Have yourinstructor SIGN–OFF your Worksheet for CREDIT.
59. WRITE the NAME of the team members who were present for the labON THE WORKSHEET.
Gate 1 Gate 2
Gate 3 Gate 4
Inverter 1 Inverter 2 Inverter 3
SWITCH
… rest of circuit intact…
AND 1
1
2
3
CLK
LED7
Lab 1: Digital TrainerFamiliarization      8 / 8

60. Turn in your filled in Worksheet for Credit.
61. Turn OFF the Trainer.
62. CAREFULLY Remove all wires so as not to bend or break the pins.Remove the IC (or use the chip remover tool) and return allcomponents to where they belong.