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1st lecture cum workshop organized by Electronics club, N.U.T.S ,IIT Jodhpur on Digital Clock

1st lecture cum workshop organized by Electronics club, N.U.T.S ,IIT Jodhpur on Digital Clock

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  • 1. ELECTRONICS CLUB IIT JODHPUR Digital electronics
  • 2. Content...1) Breadboard2) Resistors and Capacitor3) Digital4) Clock Pulse5) Logic Gates6) 555 timer7) Decade counter8) Decoder9) 7 segment LED display10) Digital clock workshop
  • 3. BREADBOARD
  • 4. WHY BREADBOARD..??• Bread + Board•Strip of metal (copper usually) runs underneath the boardconnecting the holes to one another.• Used to connect a circuit to reduce use of wires.• Easy to modify the circuit in case of errors.• No soldering required• Since it is not permanent, can be reused.• Not used for professional purposes
  • 5. Resistors…B B ROY of Great Britain has a Very Good Wife
  • 6. Types of ResistorsFIXED RESISTORS:1) Carbon Composition Resistor2) Precesion wire wound3) NIST Standards4) Power wire wound resistor5) Fuse resistors6) Carbon film resistors7) Metal Film resistors8) Foil Resistors9) Filament resistors10) Power Film resistorsVARIABLE RESISTORS1) Rheostat2) Potentiometer3) Preset
  • 7. Capacitance..• Capacitance is the measure of capacitor to STORECHARGE.•Units of capacitance Farads, pF, uF• Q= C*V• Charging and Discharging• Also used for coupling• Allows AC to pass through and blocks DC.
  • 8. TYPES OF CAPACITOR1) Electrolytic capacitor2) Non- Electrolytic capacitor3) Variable Capacitance (varicap)Other types capacitor Ceramic Capacitor Mica Capacitor Mylar Capacitor Dielectric Capacitor Film Capacitor Radial Lead type capacitor Axial Lead type capacitor Tantalum Electrolytic Capacitor
  • 9. LETS BEGIN THE MAIN SECTION…!!
  • 10. • DIGITAL• ANALOG
  • 11. DIGITAL ELECTRONICSDigital electronics represent signals by discrete bands of analog levels,rather than by a continuous range. All levels within a band represent thesame signal state.If the individual values of the signal at the various intervals areapproximated to certain precision rather than being noted precisely, theresultant signal is called a digital signal, the process being calledquantization.
  • 12. DIGITAL ELECTRONICS• Consists of only two states.• Low state refers to 0 V.• High state refers to 5 V.
  • 13. DESIGNING A DIGITAL CLOCK
  • 14. APPLICATIONS•Small and Inexpensive•Digital Clock•Timers in Microwaves, cars ,televisions, AC etc
  • 15. What do we need?•A display•Something that counts – Counter•Speed controlling of counter
  • 16. HOW DO WE COUNT..???
  • 17. Using a 4029 counter
  • 18. How to generate Clock ? 555 Astable mode OUTPUT
  • 19. TIME TO DISPLAY
  • 20. FINAL CIRCUIT555
  • 21. CLOCK• In digital electronics, system clock is the basic timingunit.•System clock is a device which generates a periodictrain of clock pulses.•The basic time interval during which logic operationmust be performed is called clock cycle time. clock cycle time = 1 period of clock waveform
  • 22. CLOCK PULSE
  • 23. INTEGRATED CIRCUITS (IC)• Integrated circuit originally referred to aminiaturized electronic circuit consisting of semiconductordevices, as well as passive components bonded to asubstrate or circuit board.• In short, a package of complex circuit to perform a task.• The circuit in the IC may be even more tiny but it isenclosed in bigger box for ease of handling.• It can be considered to be a black box doing you work..!! :P
  • 24. GATESAny binary operation (addition, multiplication etc) can beimplemented using logic gates.Basic Gates AND OR NOTDerived Gates NAND NOR Ex-OR
  • 25. VOLTAGE REGULATOR• It produces fixed DC output voltage from variable DC.•A device which converts pulsating DC to fixed DC at output.• Mainly two types - Fixed - Variable
  • 26. FIXED 1) 78XX series is positive voltage regulator. 2) 79XX series is negative voltage regulator.• 1st 2 digits indicate the sign and XX indicates the output voltage. Eg. IC 7805- +ve voltage regulator giving +5V at output.
  • 27. 555 TIMER OR CLOCK PULSE GENERATORUsed to generate clock pulseSo it is most commonly used IC.
  • 28. PIN CONFIGURATION
  • 29. BLOCK DIAGRAM
  • 30. • Name 555 due to 3 5kohm resistor potential dividercircuit.• Consists of 2 OPAMP used as comparator, 1 flip flopand a discharge transistor.•Comparator used to compare the voltage at input andgive output accordingly.• Flip flop is bistable multivibrator (both states arestable).
  • 31. • Non-inverting terminal of Comp1 is at +Vcc/3 .• When trigger input voltage (pin 2- inverting terminal) voltage isslightly less than +Vcc/3  resets flip flop (R=1)  Q=0 transistor cut off  Capacitor charges• Inverting terminal of Comp2 is at +2Vcc/3.• When threshold voltage (pin 6- non inverting terminal) voltageslightly more than +2Vcc/3  sets flip flop (S=1)  Q= 1 transistor saturates  Capacitor discharges.• Pin 1  Ground• Pin 8  +Vcc• Pin 4  Reset (if gnd, prevents device from working)• Pin 3  Output
  • 32. APPLICATIONS• Monostable Multivibrator• Astable Multivibrator• Voltage controlled divider• Pulse position modulator (PPM)• Pulse amplitude modulator (PAM)• Frequency shift keying (FSK)• Ramp generator
  • 33. MONOSTABLE MULTIVIBRATOR• Pin 6 and 7 are shorted.• 1 stable state.• Transistor changes state when trigger is given.• Produces gating pulse.
  • 34. ASTABLE MULTIVIBRATOR
  • 35. • Pin 2 and 6 are shorted• Also called ‘Free running multivibrator’• Both states are temporary.• The states keep changing without trigger pulse.
  • 36. • A duty cycle is the time that an entity spends in an active state as a fraction of thetotal time under consideration. Duty cycle = (W/T)* 100 = (R1+R2)/ (R1+2R2) *100 = 0.693 (R1+ 2R2)*C Frequency, f= 1.44__ [(R1+2R2)*C] T – time period W – Width R1, R2 – Resistances in ohms C – Capacitance in farads f – Frequency in hertzThe time period can be split into two parts: T = Tm + TsMark time (output high): Tm = 0.7 (R1 + R2) C1Space time (output low): Ts = 0.7 R2 C1
  • 37. LETZ BEGIN FIRST STEP….!!GENERATE CLOCK PULSE..!!
  • 38. COUNTER• It is a special kind of register, designed to count the number of clockpulses arriving at its input.Applications:1) To count number of clock pulses.2) To measure frequency.3) For frequency division.4) Measurement of time.5) To generate a pulse of known width.6) To generate timing pulses for horizontal and vertical generator in TV.7) For direct counting of objects moving at a high speed.8) In digital voltmeter etc.
  • 39. MODULUS OF A COUNTER:• The modulus of a counter is the total number of states throughwhich the counter can progress.• The natural count is given by 2^n, where n is the number of flipflops used.TYPES OF COUNTER:1) Ripple or asynchronous counter2) Synchronous counter3) Combination counter
  • 40. DECADE COUNTER• It has a modified count.•By using 4 negative edge triggered J-K flip flops,Mod- 16 counter can be constructed.• By using feedback, 6 states are skipped making itMod-10 counter.
  • 41. Up- Down Counter- IC 4029• Synchronous counter so its output changes preciselytogether with change in clock pulse.• The count occurs as clock input becomes high (positiveedge triggered).• Up/Down determines the direction of counting:High  Up  4 bit binary 0 to 15Low  Down  decade 0 to 9• Preset and Carry in terminal is low for normaloperation.
  • 42. PIN CONFIGURATIONGives 4 bit BCD (Binary Coded Decimal) output.
  • 43. PIN CONNECTIONSPIN 1- Preset – GroundPIN 2, 6, 11, 14 – OutputPIN 3, 4, 12, 13 – Input – GroundPIN 5 – Carry In – OpenPIN 7 – Carry out – OpenPIN 8 – GroundPIN 9 – binary/decade – LowPIN 10 – up/down – HighPIN 15 – ClockPIN 16 - +Vcc
  • 44. LED Display PIN FUNCTION 1 Segment E 2 Segment D 3 Common Anode 4 Segment C 5 Decimal point 6 Segment B 7 Segment A 8 Common Anode 9 Segment F 10 Segment G
  • 45. • Types of LED display - Common anode type. - Common cathode type.• We will be using common anode type.• Active- low output decoder is used for common anode type display.• Current limiting resistors are connected between LED and ground.
  • 46. NOW WE CAN COUNT THE CLOCKPULSE… BUT IN BCD CODE… WE NEED IN 7 Segment… WHAT NOW…???
  • 47. IC 7447 Pin Configuration
  • 48. IC 7447• IC 7447 is used to convert BCD to 7- segment code.• It has 4 input lines and 7 output lines to drive 7 segmentdisplay.• The output terminals are connected to respective segment(a through g) of the display.• It is active- low output decoder.• LT (Lamp Test) : Used to check the segments of LED display. Connect LT to logic 0 to check. Usually it is connected to logic 1.
  • 49. TRUTH TABLE
  • 50. PIN CONNECTIONSPIN 1  Input B  Connected to Output B of 4029 (Pin 11)PIN 2  Input C  Connected to Output C of 4029 (Pin 14)PIN 3  Lamp test  Connected to +VccPIN 4  Blank out  OpenPIN 5  Blank Input  +VccPIN 6  Input D  Connected to Output D of 4029 (Pin 2)PIN 7  Input A  Connected to Output A of 4029 (Pin 6)PIN 8  GroundPIN 9  e  Connected to Pin 1 of Led DisplayPIN 10  d  Connected to Pin 2 of Led DisplayPIN 11  c  Connected to Pin 4 of Led DisplayPIN 12  b  Connected to Pin 6 of Led DisplayPIN 13  a  Connected to Pin 7 of Led DisplayPIN 14  g  Connected to Pin 10 of Led DisplayPIN 15  f  Connected to Pin 9 of Led DisplayPIN 16  +Vcc
  • 51. LETS COMPLETE THEDIGITAL CLOCK… 
  • 52. THANK YOU…!!!