1 / 44

OBJECTIVES

OBJECTIVES. After studying Chapter 12, the reader should be able to: Prepare for ASE Electrical/Electronic Systems (A6) certification test content area “A” (General Electrical/Electronic Systems). Explain capacitance. Describe how a capacitor can be used to filter electrical noise.

emilia
Download Presentation

OBJECTIVES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. OBJECTIVES After studying Chapter 12, the reader should be able to: • Prepare for ASE Electrical/Electronic Systems (A6) certification test content area “A” (General Electrical/Electronic Systems). • Explain capacitance. • Describe how a capacitor can be used to filter electrical noise. • Describe how a capacitor can store an electrical charge. • Explain how a capacitor circuit can be used as a timer circuit.

  2. CAPACITANCE • Capacitance is the ability of an object or surface to store an electrical charge. FIGURE 12-1 A Leyden jar can be used to store an electrical charge.

  3. CAPACITOR CONSTRUCTION AND OPERATION • A capacitor consists of two conductive plates with an insulating material between them. • The insulating material is commonly called a dielectric.

  4. CAPACITOR CONSTRUCTION AND OPERATION • The dielectric constant is the relative strength of a material against the flow of electrical current. • The higher the number is, the better the insulating properties.

  5. CAPACITOR CONSTRUCTION AND OPERATION FIGURE 12-2 This simple capacitor, made of two plates separated by an insulating material, is called a dielectric.

  6. CAPACITOR CONSTRUCTION AND OPERATION • Current continues until the voltage charge across the capacitor plates becomes the same as the source voltage. FIGURE 12-3 As the capacitor is charging, the battery forces electrons through the circuit.

  7. CAPACITOR CONSTRUCTION AND OPERATION • The positive plate of the capacitor and the positive terminal of the battery are also at equal positive potentials. • There is then a voltage charge across the battery terminals and an equal voltage charge across the capacitor plates. FIGURE 12-4 When the capacitor is charged, there is equal voltage across the capacitor and the battery. An electrostatic field exists between the capacitor plates. No current flows in the circuit.

  8. CAPACITOR CONSTRUCTION AND OPERATION FIGURE 12-5 The capacitor is charged through one circuit (top) and discharged through another (bottom).

  9. CAPACITOR CONSTRUCTION AND OPERATION FIGURE 12-6 Capacitor symbols are shown in electrical diagrams. The negative plate is often shown curved.

  10. FACTORS OF CAPACITANCE • Capacitance is governed by three factors. • The surface area of the plates • The distance between the plates • The dielectric material

  11. FACTORS OF CAPACITANCEMeasurement of Capacitance • Capacitance is measured in farads, which is named after Michael Faraday (1791–1867). • The symbol for farads is F.

  12. FACTORS OF CAPACITANCEMeasurement of Capacitance • The capacitance of a capacitor is proportional to the quantity of charge that can be stored in it for each volt difference in potential between its plates. • C = Q/V • Where C is capacitance in farads, Q is the quantity of stored electrical charge in coulombs, and V is the difference in potential in volts.

  13. FACTORS OF CAPACITANCEMeasurement of Capacitance • Therefore, stored electric charge can be calculated using the formula: • Q = CV • The difference in potential or voltage of the capacitor can be calculated using the formula: • V = Q/C

  14. CAPACITOR USES • Spike Suppression • Noise Filtering • Supplemental Power Source • Timer Circuits • Computer Memory • Condenser Microphones

  15. CAPACITOR USES FIGURE 12-7 A capacitor blocks direct current (DC) but passes alternating current (AC). A capacitor makes a very good noise suppressor because most of the interference is AC and the capacitor will conduct this AC to ground before it can reach the radio or amplifier.

  16. CAPACITOR USESCapacitors in Parallel Circuits • Capacitance can be increased in a circuit by connecting capacitors in parallel. FIGURE 12-8 Capacitors in parallel effectively increase the capacitance.

  17. CAPACITOR USESCapacitors in Parallel Circuits • The following is the formula for calculating total capacitance in a circuit containing capacitors in parallel. • CT= C1 + C2 + C3 ...

  18. CAPACITOR USESCapacitors in Series Circuits • Capacitance can be decreased in a circuit by capacitors in series. FIGURE 12-9 Capacitors in series decrease the capacitance.

  19. CAPACITOR USESCapacitors in Series Circuits • Following is the formula for calculating total capacitance in a circuit containing two capacitors in series.

  20. CAPACITOR USESSuppression Capacitors • Capacitors are installed across many circuits and switching points to absorb voltage fluctuations. • Among other applications, they are used across the following: • The primary circuit of some electronic ignition modules • The output terminal of most generators (alternators) • The armature circuit of electric motors

  21. SUMMARY • Capacitors (condensers) are used in numerous automotive applications. • Capacitors can block direct current and pass alternating current. • Capacitors are used to control radio-frequency interference and are installed in various electronic circuits to control unwanted noise. • Capacitors connected in series reduce the capacitance whereas if connected in parallel increase the capacitance.

  22. REVIEW QUESTIONS • How does a capacitor store an electrical charge? • How should two capacitors be electrically connected if greater capacitance is needed? • How can a capacitor be used as a power source? • How can a capacitor be used as a noise filter?

  23. CHAPTER QUIZ • A capacitor _____. • Stores electrons • Passes AC • Blocks DC • Does all of the above

  24. CHAPTER QUIZ • A capacitor _____. • Stores electrons • Passes AC • Blocks DC • Does all of the above

  25. CHAPTER QUIZ 2. To increase the capacity, capacitors should be connected in _____. • Series • Parallel • With resistors connected between the leads • Series-parallel

  26. CHAPTER QUIZ 2. To increase the capacity, capacitors should be connected in _____. • Series • Parallel • With resistors connected between the leads • Series-parallel

  27. CHAPTER QUIZ 3. Capacitors are commonly used as a _____. • Voltage supply • Timer • Noise filter • All of the above

  28. CHAPTER QUIZ 3. Capacitors are commonly used as a _____. • Voltage supply • Timer • Noise filter • All of the above

  29. CHAPTER QUIZ 4. A charged capacitor acts like a _____. • Switch • Battery • Resistor • Coil

  30. CHAPTER QUIZ 4. A charged capacitor acts like a _____. • Switch • Battery • Resistor • Coil

  31. CHAPTER QUIZ 5. The unit of measurement for capacitor rating is called the _____. • Ohm • Volt • Farad • Ampere

  32. CHAPTER QUIZ 5. The unit of measurement for capacitor rating is called the _____. • Ohm • Volt • Farad • Ampere

  33. CHAPTER QUIZ 6. Two technicians are discussing the operation of a capacitor. Technician A says that a capacitor can create electricity. Technician B says that a capacitor can store electricity. Which technician is correct? • Technician A only • Technician B only • Both Technicians A and B • Neither Technician A nor B

  34. CHAPTER QUIZ 6. Two technicians are discussing the operation of a capacitor. Technician A says that a capacitor can create electricity. Technician B says that a capacitor can store electricity. Which technician is correct? • Technician A only • Technician B only • Both Technicians A and B • Neither Technician A nor B

  35. CHAPTER QUIZ 7. Capacitors block the flow of _____ current but allow _____ current to pass. • Strong; weak • AC; DC • DC; AC • Weak; strong

  36. CHAPTER QUIZ 7. Capacitors block the flow of _____ current but allow _____ current to pass. • Strong; weak • AC; DC • DC; AC • Weak; strong

  37. CHAPTER QUIZ 8. To increase the capacity what could be done? • Connect another capacitor in series. • Connect another capacitor in parallel. • Add a resistor between two capacitors. • Both a and b

  38. CHAPTER QUIZ 8. To increase the capacity what could be done? • Connect another capacitor in series. • Connect another capacitor in parallel. • Add a resistor between two capacitors. • Both a and b

  39. CHAPTER QUIZ 9. A capacitor can be used in what components? • A microphone • A radio • A speaker • All of the above

  40. CHAPTER QUIZ 9. A capacitor can be used in what components? • A microphone • A radio • A speaker • All of the above

  41. CHAPTER QUIZ 10. A capacitor used for spike protection will normally be placed in _____ to the load or circuit. • Series • Parallel • In either series or parallel • In parallel with a resistor in series

  42. CHAPTER QUIZ 10. A capacitor used for spike protection will normally be placed in _____ to the load or circuit. • Series • Parallel • In either series or parallel • In parallel with a resistor in series

  43. END

More Related