0
CAPACITOR BLOCKS DC SUPPLY .THERE ARE MAINLY TWO ANSWERS
1.CAPACITIVE REACTANCE Xc=1/( 2*3.1416*F*C) , HERE THE FREQUENCY OF DC SUPPLY IS ZERO .HENCE THE REACTANCE VALUE IS INFINITY .SO IT BLOCKS THE DC SUPPLY.
2.CURRENT THROUGH A CAPACITOR IS PROPORTIONAL TO THE RATE OF CHANGE OF CURRENT . BUT IN THE CASE OF DC SUPPLY, THE RATE OF CHANGE OF CURRENT IS ZERO. HENCE THE CAPACITOR CURRENT IS ALSO ZERO.
H.L.kiran
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoA capacitor blocks DC, while allowing AC to pass through it, because of its nature in resisting a change in voltage. The equation of a capacitor is ...
dv/dt = i/c
... which means that the rate of change of the voltage is proportional to current and inversely proportional to capacitance.
If you place DC across a capacitor, it will initially allow current to flow. As it charges, if the current is coming through a resistor, the current will exponentially decrease. (If the current source is a constant current source, the capacitor will charge linearly, until the underlying voltage source is exhausted.) At some point, the voltage on the capacitor will match the voltage of the source, and current will stop. No current means infinite resistance, by Ohm's Law. Thus, the DC is blocked.
If, however, the input voltage is changing, either because its AC, or because it represents some kind of signal, then the capacitor will come into equilibrium with an average voltage equal to the DC component of the signal. If you place the capacitor in series between two nodes, the output node will have only the varying signal present, with the DC bias removed.
In this configuration, the capacitor is functioning as a high pass filter. This is often done in AC coupled amplifiers so as to remove the DC component of a signal so as to not affect the DC bias of the following stage.
You can make a low pass filter just as easily. Just place the capacitor in parallel with the signal, and DC will go around the capacitor, while AC/Signal will be shunted through the capacitor.
Often, there are other components, such as resistors and inductors, in a low pass or high pass filter. They simply go into the design of the filter and what we call its roll-off frequency.
Wiki User
∙ 13y agoA: Consider a capacitor a container when it if full it has reached status quo With AC the container is filled then emptied then fill again and so on.
Add your answer:
Earn +20 pts
Can we use AC capacitor in surge suppression circuit DC?
A capacitor is a capacitor, no matter what circuits you use it in. There is no difference between one used in AC and one in DC, except perhaps the size that is appropriate.
What are the roles of a diode and a capacitor in an AC-DC converter?
An AC-DC converter you can operate a device on AC instead of batteries. ~bobbyjack~ : D
Why capacitor used in a DC inverter?
capacitor is component used to store and release the electric charge.and also it has feature to block the dc but bypass ac.and inverter is device which converts ac to dc and then again ac
What is ac ground?
If a circuit is grounded through a capacitor it is referred to as AC ground because ac signal can pass through the capacitor DC level is blocked
Why coupling capacitor block DC in amplifier?
capacitors at input block dc and allows ac only. so absolute none of the dc enters the circuit. They are called decoupling capacitors or blocking caps. -DANNY S
Electric device blocks dc but allows ac?
A capacitor blocks DC but allows AC.
What is the use of coupling capacitor?
It allows AC current to go through, but blocks DC current.
How can a normal person understands a embedded programming?
Simply how capacitor blocks dc and allows ac after charging?
What capacitor blocks either ac or DC?
Always DC.
Why a capacitor does not accept AC?
A capacitor conducts AC but do not conduct DC because it is meant to store charge.
What is an electrical capacitor?
Electricity is either alternating current or direct current, abbreviated AC or DC. An AC/DC Capacitor can be used in either an AC or DC current.
Can we use AC capacitor in surge suppression circuit DC?
A capacitor is a capacitor, no matter what circuits you use it in. There is no difference between one used in AC and one in DC, except perhaps the size that is appropriate.
What devices can be used to block DC and pass AC?
simple capacitor can do this job (to block dc and pass ac).
What are the roles of a diode and a capacitor in an AC-DC converter?
An AC-DC converter you can operate a device on AC instead of batteries. ~bobbyjack~ : D
Why capacitor used in a DC inverter?
capacitor is component used to store and release the electric charge.and also it has feature to block the dc but bypass ac.and inverter is device which converts ac to dc and then again ac
Why don't capacitors allow DC current to pass?
A capacitor allows AC (to pass through) because capacitors resist a change in voltage.. The capacitor need change resist in Input signal
What type of function of capacitor in dc power supply?
It filters ac to pure dc
