Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Electric Circuit
Document related concepts
Transcript
241-205 12 Electric Circuit Electric Circuits Capacitors DK Capacitors 1 Chapter 12 Capacitors Electric Circuit Capacitors 2 OUTLINE Electric Circuit Capacitors 3 Electric Circuit Capacitors 4 Electric Circuit Capacitors 5 Electric Circuit Capacitors 6 Capacitance is a measure of a capacitor’s ability to store charge. Electric Circuit Capacitors 7 Electric Circuit Capacitors 8 Electric Circuit Capacitors 9 Electric Circuit Capacitors 10 A capacitor stores energy in the form of an electric field that is established by the opposite charges stored on the two plates. Electric Circuit Capacitors 11 Electric Circuit Capacitors 12 The energy stored by the capacitor is : Electric Circuit Capacitors 13 The voltage rating specifies the maximum dc voltage that can be applied without risk of damage to the device. Electric Circuit Capacitors 14 The temperature coefficient indicates the amount and direction of a change in capacitance value with temperature. A positive temperature coefficient mean that the capacitance increase with an increase in temperature or decrease with a decrease in temperature. A negative temperature coefficient mean that the capacitance decrease with an increase in temperature or increase with a decrease in temperature. Electric Circuit Capacitors 15 The dielectric of any capacitor will conduct some very small amount of current. Thus, the charge on a capacitor will eventually leak off. Equivalent circuit for non ideal capacitor Electric Circuit Capacitors 16 Capacitance is directly proportional to the physical size of the plates as determined by the plate area, A. Electric Circuit Capacitors 17 Capacitance isinversely proportional to the distance between the plates. Electric Circuit Capacitors 18 Electric Circuit Capacitors 19 The measure of a material’s ability to establish an electric field is called the dielectric constant or relative permittivity, symbolized by Electric Circuit Capacitors 20 Electric Circuit Capacitors 21 Electric Circuit Capacitors 22 Electric Circuit Capacitors 23 Electric Circuit Capacitors 24 Electric Circuit Capacitors 25 Electric Circuit Capacitors 26 Electric Circuit Capacitors 27 Electric Circuit Capacitors 28 Electric Circuit Capacitors 29 Electric Circuit Capacitors 30 Capacitor values are indicated on the body of the capacitor either by typographical labels or by color codes. Typographical labels consist of letters and numbers that indicate various parameters such as capacitance, voltage rating and tolerance. For example ceramic capacitor marked .001 or .01 has units of microfarad or 50 or 330 has units of microfarad. some case 103 mean 10,000 pF Electric Circuit Capacitors 31 Electric Circuit Capacitors 32 Electric Circuit Capacitors 33 Electric Circuit Capacitors 34 Electric Circuit Capacitors 35 Electric Circuit Capacitors 36 Electric Circuit Capacitors 37 The voltage across each capacitor in series is inversely proportional to its capacitance value. Electric Circuit Capacitors 38 Electric Circuit Capacitors 39 Electric Circuit Capacitors 40 Electric Circuit Capacitors 41 Electric Circuit Capacitors 42 What is the total capacitance? and what is the voltage across each capacitor? Electric Circuit Capacitors 43 Electric Circuit Capacitors 44 Electric Circuit Capacitors 45 Electric Circuit Capacitors 46 Electric Circuit Capacitors 47 Electric Circuit Capacitors 48 Electric Circuit Capacitors 49 Electric Circuit Capacitors 50 Electric Circuit Capacitors 51 Exponential voltage curves for the charging of an RC circuit Electric Circuit Capacitors 52 Exponential voltage curves for the discharging of an RC circuit Electric Circuit Capacitors 53 VF and IF are the final values of voltage and current. Vi and Ii are the initial values of voltage and current. Electric Circuit Capacitors 54 Electric Circuit Capacitors 55 Electric Circuit Capacitors 56 Determine the capacitor voltage 50 s after the switch is closed if the capacitor is initially uncharged, Draw the charging curve. Electric Circuit Capacitors 57 Electric Circuit Capacitors 58 Determine the capacitor voltage at a point in time 6 ms after the switch is closed. Draw the discharging curve. Electric Circuit Capacitors 59 Electric Circuit Capacitors 60 Electric Circuit Capacitors 61 How long will it take the initially capacitor to charge to 75 V? What is the capacitor voltage 2 ms after the switch is closed? Electric Circuit Capacitors 62 Electric Circuit Capacitors 63 Electric Circuit Capacitors 64 Electric Circuit Capacitors 65 Decreasing exponential formula Electric Circuit Capacitors 66 Increasing exponential formula Electric Circuit Capacitors 67 How long will it take the capacitor to discharge to 25 V when the switch is closed ? Electric Circuit Capacitors 68 Calculate the voltage across the capacitor every 0.1 ms for one period of input. Then sketch the capacitor waveform Electric Circuit Capacitors 69 Electric Circuit Capacitors 70 Electric Circuit Capacitors 71 Electric Circuit Capacitors 72 Electric Circuit Capacitors 73 Electric Circuit Capacitors 74 Electric Circuit Capacitors 75 Electric Circuit Capacitors 76 Electric Circuit Capacitors 77 Electric Circuit Capacitors 78 Determine the capacitive reactance when the frequency of a sinusoidal voltage is 1 kHz. Electric Circuit Capacitors 79 The reactance of a capacitor is analogous to the resistance of a resistor. Electric Circuit Capacitors 80 Determine the rms current. Electric Circuit Capacitors 81 Electric Circuit Capacitors 82 Electric Circuit Capacitors 83 Determine the reactive power. Electric Circuit Capacitors 84 Electric Circuit Capacitors 85 Electric Circuit Capacitors 86
