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Revision analog electronics

Prepared by: Cesar Mendoza Applied Technology Teacher. Revision analog electronics. Revison :. Module 1: Semiconductor –Diode Module 2: BJT Transistor Module 3: Operational Amplifier Module 4: Application of Semiconductor Module 5: Project.

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Revision analog electronics

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  1. Prepared by: Cesar Mendoza Applied Technology Teacher Revision analog electronics

  2. Revison: Module 1: Semiconductor –Diode Module 2: BJT Transistor Module 3: Operational Amplifier Module 4: Application of Semiconductor Module 5: Project

  3. Project- automatic fan controller Operational Amplifier

  4. What is Operational Amplifier? Operational Amplifier is an electronic devices which amplifies small ac or dc signal and perform basic operation as addition, subtraction multiplication and so on. Fig. Operational amplifier (LM741)

  5. Operational Amplifier Op Amp has 2 inputs Voltage Output Inverting Input +V _ Vin1 V out + V in2 -V Non-Inverting Input Inverting Input- the input where output will change to the opposite sign. Non-Inverting Input- the input where output will not change to the opposite sign.

  6. Operational Amplifier Op Amp has voltage supply, +V and -V Positive (+) supply voltage +V _ Vin1 V out + V in2 -V Negative (-) supply voltage

  7. Operational Amplifier OP-AMP is an IC or Integrated Circuit made of many components

  8. Characteristic of Operational amplifier……. High input impedance Output impedance is zero Open loop gain is high (10,000x)

  9. What is the use of Operational Amplifier? Operational Amplifier -amplifies small AC or DC Signal. Operational Amplifier can also do basic operation : add, subtract, multiply (amplify) etc.

  10. +V V out _ Vin1 + V in2 V out = A x (Vin2 – Vin1) -V Gain (A) = V out V in Open Loop Gain = 100,000 x

  11. Op Amp as Comparator. Op Amp compares Vin1 and Vin2: If Vin 2 > Vin1 therefore: V out = +V If Vin1 > Vin2 V out = -V

  12. Op Amp as Comparator. Op Amp compares Vin1 and Vin2: If Vin 2 > Vin1 therefore: V out = +V If Vin1 > Vin2 V out = -V Example: The +V= 15V and; If Vin1= 4mV and –V = -15V Vin2 = 6 mV Therefore: Vin2 > Vin2 So, Vout= 15V

  13. Project- automatic fan controller Operational Amplifier

  14. Pin Number or Configuration Fig. LM 311 Op Amp IC Fig. LM 741 Op Amp IC

  15. Pin Number or Configuration Pin Configuration is the assignment of Pin number with the corresponding use.

  16. Pin Number or Configuration

  17. Other uses of Op Amp. Inverting Amplifier Non inverting amplifier Summing Amplifier Differential amplifier Voltage follower Integrator Differentiator

  18. Revision Question ________________is an electronic devices which amplifies small ac or dc signal and perform basic operation as addition, subtraction multiplication and so on. ________________- input of Op Amp where the output is changed to opposite sign. ________________ the open loop gain of Op Amp. ________________ use of an Op Amp with no feedback. where it compares Vin2 and Vin2. ________________ the arrangement of Pin of an integrated circuit of IC. ________________is the Pin number of the output of a LM741 operational amplifier.

  19. Application of Op amp.

  20. Project- automatic fan controller Do you understand now the purpose of the operational amplifier in this circuit? Answer: To Compare input pin 3 and pin 2.

  21. What is the Input in Pin 3 and Pin 2? Voltage Divider Circuit (Reference)

  22. What is the Input in Pin 3 and Pin 2? Voltage Divider Circuit (Sensor)

  23. Voltage Divider… Vcc Potentiometer of Variable Resistor A A R1 B B R2 C C

  24. So, Vin2 could be from 0-12V?

  25. And Vin1 depends on the value of NTC?

  26. What is NTC? NTC is a Thermistor or Thermal Resistor that converts Temperature to Change in Resistance. It has two (2) types; NTC and PTC NTC – Negative Temperature Coefficient. As temp increses, resistance Decrease. PTC – Positive Temperature Coefficient. As tempincrease, resistance increases. Resistance , ohm Resistance , ohm Temperature, deg C Temperature, deg C NTC PTC

  27. Voltage Divider… Vcc The voltage VC changes the resistance of the Thermistor changes. A R1 B VB = Vcc x RNTC . R1 + RNTC C

  28. Revision Question ________________ a circuit that divided the voltage proportionally with the value of resistors connected in series. _______________ a thermal resistor that converts temperature in change in resistance. _______________ use of an Op Amp with no feedback. where it compares Vin2 and Vin2. ________________ the arrangement of Pin of an integrated circuit of IC.

  29. Voltage Divider… Vcc Vc = Vcc x RNTC . R1 + RNTC A R1 B If R1 = 10,000 RNTC = 10,000 @ 30 deg C VB = 10V x ( 10,000/20,000) VB = 5V C

  30. Voltage Divider… Vcc = 10V If R1 = 10,000 RNTC = 10,000 @ 30 deg C VB = 10V x ( 10,000/20,000) VB = 5V If RNTC = 8,000 @ 50 deg C VB = 10V x (8,000/ 18,000) VB = 4.44 V A R1 B C

  31. So, Vin2 could be from 0-12V?

  32. Potentiometer. IF Vcc = 10 V Therefore: VBC = 0V – 10 V Vcc= 10V A B C V

  33. Potentiometer. Vcc= 10V Vcc= 10V A A B B C C V V VBC = 10V VBC = 0V

  34. Potentiometer. Vcc= 10V A B C V So, in the middle VBC = 5V

  35. I will combine potentiometer circuit and the Voltage divider circuit with NTC Vcc Vcc= 10V A A R1 B B C C

  36. So, this 2 circuit is the input to the operational amplifier

  37. So, this 2 circuit is the input to the operational amplifier IN THIS FIGURE ONLY So, if Vin2 > Vin3 = Vout = +12V

  38. Voltage Output IN THIS FIGURE ONLY So, if Vin2 > Vin3 = Vout = +12V The Vout = +12V will activate the Driver Transistors

  39. What is Transistor? BJT? Transistor is derived from the combination of two words, “Transfer-Resistance”. It means that it is a device, which transfers a low resistance into a circuit having high resistance BJT - is a three-terminal semiconductor device, whose operation depends upon the flow of electric charge carriers within the solid.

  40. Transistor…

  41. Transistor ID. Low Power Small Packages Medium Power Medium Packages High Power big Packages

  42. The base is 0.7V (or slightly more) positive of its emitter The base is 0.7V (or slightly more) positive of its emitter The base is 0.7V (or slightly more) positive of its emitter Transistor Action… • Its emitter is its negative terminal. • The collector is several volts positive of its emitter. • The base is 0.7V (or slightly more) positive of its emitter

  43. Use of Transistor. • Transistor is used as: • Switch • Amplifier. Will Turn ON the Transistor Small Base Current

  44. Transistor as switch… When switch is closed: Small base current is applied to the base. LED B is DIM (small current) Transistor is turned ON allowing emitter-collector current which is bigger. LED C will have a bright light (big current)

  45. Voltage Output IN THIS FIGURE ONLY So, if Vin2 > Vin3 = Vout = +12V The Vout = +12V will activate the Driver Transistors

  46. R Base So if the output of the OP Amp is Hi, it will provide base current to the transistor making it ON thus Energizing the Relay.

  47. What is a Relay? Relay – an electrically operated switch. It is made of coil and set of contacts, NO NC.

  48. AC power Supply Small Current Med Current R Base Big current

  49. Conclusion We Learned About: Application of Semiconductor Devices: transistor diode, etc.. Learned the operation of transistor WE learn operational amplifier and it uses. We make use of LED as indicator of current.

  50. Thank You For Listening

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