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Capacitors store electrical charge.

Imagine we have a capacitor. At time 0 seconds we connect a DC voltage across the capacitor - immediately as the voltage is connected the capacitor is at 0 volts and the maximum current (relative to the circuit resistance) flows. At this extreme the capacitor can be treated as a short circuit, so for high frequency AC volts we should treat a capacitor as being a short circuit.

As time passes the current in the circuit will go down and the voltage of the capacitor will go up - this is because as the capacitor gains more charge it gains more voltage, lowering the voltage across any resistance in the circuit consequently lowering the current in the circuit. When the capacitor is virtually full no current will flow at all and the voltage across the capacitor will equal the DC source voltage. At this extreme the capacitor can be treated as an open circuit, so for low frequency AC (allowing the capacitor to fill up before the current alternates) we can treat the capacitor as being an open circuit.

Technically, it is not an open/closed circuit when it comes to AC because the capacitance will results in a signal lag or lead. However, if the frequency is low/high enough the lag/lead is often negligable.

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How capcitor introduce phase shift?

A capacitor introduces a phase shift in an alternating current (AC) circuit because it does not allow current to change instantaneously. When an AC voltage is applied, the capacitor charges and discharges, causing the current to lead the voltage by 90 degrees in a purely capacitive circuit. This phase difference results from the time it takes for the capacitor to build up and release charge, which affects the relationship between voltage and current in the circuit. Thus, the presence of a capacitor alters the phase relationship between these two electrical quantities.


But in DC ciruit there is no current when capacitor is connected?

This is because when you introduce a capacitor, the circuit is no longer a DC circuit. If you're using a multimeter see if there is an AC setting to measure the current.


Is it true the alternating current can pass through a capacitor while the direct current cannot pass through?

Yes.


What is it mean to say that an alternating current leads or lags an alternating emf?

It is another way of saying that the circuit is capacitive reactive circuit. Look up the mnemonic ELI the ICE man. ELI, voltage leads the current in an inductive circuit. ICE, current leads the voltage in a capacitive circuit.


Why was the capacitor discharging current negative?

When a capacitor is discharging, current is flowing out of the capacitor to other elements in the circuit, similar to a battery. Current flowing out of an element, by convention, is defined as negative current, while current flowing into an element, such as a resistor, is defined as positive current. Thus a discharging capacitor will always have a negative current.

Related Questions

Can alternative current be turned into direct current?

By "alternative" I presume you mean "alternating". Yes it can by using a device called a rectifier then some sort of bypass circuit to conduct the alternating current to ground, usually just a capacitor.


A lamp is connected to a battery if a capacitor is inserted in the positive wire between the battery and the lamp what will happen?

large capacitors will become charged in a fraction of a second if a DC voltage is applied to its terminalsonce a capacitor becomes fully charge it acts as an open circuit to direct current in other words, once the capacitor charged by a DC voltage, the current will cease to flow in the branch of the circuit which contains the capacitor.a capacitor also offers opposition known as (capacitive reactance) to alternating current. it does not , however ,act as an open circuit to when an a-c alternating current voltage is applied.


When a capacitor is connected to a circuit, what happens to the current flow through the capacitor?

When a capacitor is connected to a circuit, the current flow through the capacitor initially increases and then decreases as the capacitor charges up.


What converts an alternating current to diredt current?

Alternating Current can be converted to Direct Current by using a DC Converter which contain a Bridge Circuit , a Capacitor and if needed a Transformer.CommentA 'DC converter' is normally called a rectifier.


What happens to the current in a circuit as a capacitor charges?

What happens to the current in a circuit as a capacitor charges depends on the circuit. As a capacitor charges, the voltage drop across it increases. In a typical circuit with a constant voltage source and a resistor charging the capacitor, then the current in the circuit will decrease logarithmically over time as the capacitor charges, with the end result that the current is zero, and the voltage across the capacitor is the same as the voltage source.


How capcitor introduce phase shift?

A capacitor introduces a phase shift in an alternating current (AC) circuit because it does not allow current to change instantaneously. When an AC voltage is applied, the capacitor charges and discharges, causing the current to lead the voltage by 90 degrees in a purely capacitive circuit. This phase difference results from the time it takes for the capacitor to build up and release charge, which affects the relationship between voltage and current in the circuit. Thus, the presence of a capacitor alters the phase relationship between these two electrical quantities.


Can a capacitor limit current in a circuit?

No.


Why capacitor does not store alternate current but store direct current?

Because Alternet current has both positive as well as negative cycle capacitor does not conduct for negative cycle of the Alternet current and DC all are positive cycle thats why it capacitor conduct for DC not for AC


What is use of capacitor?

It blocks direct electrical current allowing alternating current to pass


A W pf capacitor is connected into a 240 V Hz circuit. what is the current flow in this circuit?

a 30 pf capacitor is connected into a 240v, 60 hz circuit. what is the current flow into the circuit


What to expect if a resistor is placed in a dc circuit with a capacitor?

when we replace the resistor with a capacitor ,the current will flow until the capacitor charge when capacitor will fully charged there is no current through the circuit because now capacitor will act like an open circuit. for more info plz E-mailt me at "zaib.zafar@yahoo.com"


How capacitor bypass alternating current?

It passes AC through it and blocks DC