Electric Circuit Capacitors Electric Circuits Capacitors DK 12

Electric Circuit Capacitors 2 Chapter 12 Capacitors

Electric Circuit Capacitors 3 OUTLIN E

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Electric Circuit Capacitors 7 Capacitance is a measure of a capacitor’s ability to store charge.

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Electric Circuit Capacitors 11 A capacitor stores energy in the form of an electric field that is established by the opposite charges stored on the two plates.

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Electric Circuit Capacitors 13 The energy stored by the capacitor is :

Electric Circuit Capacitors 14 The voltage rating specifies the maximum dc voltage that can be applied without risk of damage to the device.

Electric Circuit Capacitors 15 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 16 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 17 Capacitance is directly proportional to the physical size of the plates as determined by the plate area, A.

Electric Circuit Capacitors 18 Capacitance isinversely proportional to the distance between the plates.

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Electric Circuit Capacitors 20 The measure of a material’s ability to establish an electric field is called the dielectric constant or relative permittivity, symbolized by

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Electric Circuit Capacitors 31 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

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Electric Circuit Capacitors 38 The voltage across each capacitor in series is inversely proportional to its capacitance value.

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Electric Circuit Capacitors 43 What is the total capacitance? and what is the voltage across each capacitor?

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Electric Circuit Capacitors 52 Exponential voltage curves for the charging of an RC circuit

Electric Circuit Capacitors 53 Exponential voltage curves for the discharging of an RC circuit

Electric Circuit Capacitors 54 V F and I F are the final values of voltage and current. V i and I i are the initial values of voltage and current.

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Electric Circuit Capacitors 57 Determine the capacitor voltage 50  s after the switch is closed if the capacitor is initially uncharged, Draw the charging curve.

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Electric Circuit Capacitors 59 Determine the capacitor voltage at a point in time 6 ms after the switch is closed. Draw the discharging curve.

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Electric Circuit Capacitors 62 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?

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Electric Circuit Capacitors 66 Decreasing exponential formula

Electric Circuit Capacitors 67 Increasing exponential formula

Electric Circuit Capacitors 68 How long will it take the capacitor to discharge to 25 V when the switch is closed ?

Electric Circuit Capacitors 69 Calculate the voltage across the capacitor every 0.1 ms for one period of input. Then sketch the capacitor waveform

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Electric Circuit Capacitors 79 Determine the capacitive reactance when the frequency of a sinusoidal voltage is 1 kHz.

Electric Circuit Capacitors 80 The reactance of a capacitor is analogous to the resistance of a resistor.

Electric Circuit Capacitors 81 Determine the rms current.

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Electric Circuit Capacitors 84 Determine the reactive power.

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