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Capacitors charge by transferring charge from one plate to the other. This is not the same as a battery, though it can seem so. They oppose a change in voltage because the two plates are close to each other, separated by the dielectric, and the transfer of charge requires current. Once charged, however, the current becomes zero. The differential equation describing a capacitor is dv/dt = i/c, or volts per second = current over capacitance.
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Why capacitor oppose change in voltage and allows current to flow?
Because that is what a capacitor does, resist a change in voltage. It holds a certain amount of energy per charge (voltage), and to change that voltage requires current proportionally to the capacitance.
If we change the polarity of capacitor in ceiling fan why it starts rotating reverse direction?
by changing the polarity of capacitor of single phase ceiling fan can we change the direction of rotation from anticlockwise to clockwise
What is the value of capacitor voltage and current after 5 time constant?
After 5 time constants, capacitor voltage/current will be about 99.3% of the input step change.
What is the use of capacitor in touch operated system?
Capacitors are used on touch screen technology. mystery of using capacitor in touch screen is the working principle of capacitor . when you touch the screen the distance between two plates inside screen will change(by pressing) and this will cause the change in capacitance and hence in voltage and this signal fed to processor to process it. and that behind the use of capacitor in touch screen.
Why does the current lead the voltage across a capacitor by 90 degree rather than lag it?
A: Because a capacitor have to have time to charge to the voltage In a capacitor, the current depends on the voltage difference across it. On AC, this makes it charge, if the voltage is increasing above zero, and discharge if the voltage is reducing towards zero. Because a capacitor has almost no internal resistance, and most loads that it is connected to have only very small resistances in series with the capacitor, the charging and discharging currents depend pretty much on the rate at which the voltage is changing. At the zero crossing point of the sine-wave, when the voltage is actually zero, the rate of change of voltage is very high (the sine-wave is at its steepest), so the current is also very high. If the voltage is positive-going, the current is positive, and if the voltage is negative-going, the current is negative. At the peak of the voltage waveform, the rate of change of voltage is zero or very low (the sine-wave is flat, and not really changing its voltage) so the current is zero, too. Since the maximum positive current occurs when the voltage is passing through zero, going positive, and the maximum negative current happens when the voltage is passing through zero, going negative, the current peaks happen 90 degrees before the voltage peaks, so the current is said to lead the voltage. This is the same as saying the voltage lags the current by 90 degrees.
Why capacitor oppose change in voltage and allows current to flow?
Because that is what a capacitor does, resist a change in voltage. It holds a certain amount of energy per charge (voltage), and to change that voltage requires current proportionally to the capacitance.
Is a higher capacitance better?
capacitor always opposes the change in voltage , at beginning it shows the initial value and after sum time it charges and shows the maximum valve . Higher capacitor has higher voltage after some time , therefore it damages the equipment.
Why capacitor charges exponentially why not linear?
because as the capacitor starts charging,the charges which are already built on capacitor opposes the further flow of charges. hence the process gets slow. thats we get sharp curve initially which gets flat further.
Can the voltage across a capacitor change instantaneously?
No, the voltage across a capacitor cannot change instantaneously. It takes time for the voltage across a capacitor to change due to the storage and release of electrical energy in the capacitor.
What is the difference between an inductor and a capacitor?
Firstly the suffix '-ance' in each of those three words indicate the properties the material exhibits. Therefore resistance is the property by which any material tends to oppose the flow of current through it. Inductance is the property by which a material opposes the change in current, or opposes an alternating current. An inductor can be appreciated simply using a coil of insulated wire, or a solenoid. Capacitance is the property by which a material opposes the change in voltage across its ends, ie how it opposes alternating voltage. A capacitor comprises of, essentially, two metallic plates separated by a dielectric (a medium which may/may not be non-conducting, but is capable to contain charge). cheers!!
How capacitor opposes the change in current?
as a voltage is applied across a capacitor charges accumulate on the plates.due to accumulation of charges,electric field between the plates develop in the direction opposite to the applied field.this field give rise to the potential across the plates.if the plates get completely charged due to the applied voltage i.e if the whole of the charge q=c(capacitance of the capacitors)xv(voltage applied) develops on the plates,then the applied voltage wiil be opposed to an extent that no further charges will induce on it.But in practice,it takes very long time for the capacitor to get completely charged due to the applied voltage..............now coming to ac circuits,having capacitor.......if the frequency of ac applied voltage is less then the voltage will change slowly.due to this at each instant large amount of charge will develop on the plates causing large opposition.vice versa to high frequency applied voltage.
How can I change the ceiling fan capacitor?
To change the ceiling fan capacitor, first turn off the power to the fan. Remove the fan blades and housing to access the capacitor. Disconnect the wires from the old capacitor and remove it. Install the new capacitor in its place and reconnect the wires. Reassemble the fan and turn the power back on to test the new capacitor.
What is the electrical property that opposes change in current?
inductance
How is the change of potential difference across the capacitor determined?
The change in potential difference across a capacitor is determined by the amount of charge stored on the capacitor and the capacitance of the capacitor. The relationship is given by V = Q/C, where V is the potential difference, Q is the charge stored on the capacitor, and C is the capacitance.
What is a one word substitute for one who opposes change?
Traditionalist
How does the energy stored in a capacitor change when the potential difference across it is doubled?
When the potential difference across a capacitor is doubled, the energy stored in the capacitor increases by a factor of four.
If we change the polarity of capacitor in ceiling fan why it starts rotating reverse direction?
by changing the polarity of capacitor of single phase ceiling fan can we change the direction of rotation from anticlockwise to clockwise
