Study guides

☆☆

Q: What effect does the series resistance of a capacitor used in a capacitor filter have on diode current and ripple voltage compared with an ideal capacitor of no resistance?

Write your answer...

Submit

Still have questions?

Continue Learning about Movies & Television

Voltage = (current) x (resistance) Current = (voltage)/(resistance) Resistance = (voltage)/(current)

AC can pass through a capacitor. The higher the frequency of AC the lower the reactance (like resistance). The current and applied voltage are 90 degrees out of phase the current leading the voltage by this amount.

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.

Current through a capacitor is proportional to the rate of change of voltage across it. But in the case of dc supply, the rate of change of voltage is zero. Hence the capacitor current is also zero. Capacitive reactance -- the "resistance" of a capacitor to current flow -- is found by 1/(2*pi*f*C). For high frequencies, this "resistance" is low, allowing current flow. The lower the frequency, the higher this "resistance" is. DC or direct current is consider "zero" Hertz frequency and the capacitive reactance ("resistance") at this point is infinite, allowing no current flow at all. So, the higher the frequency, the easier it is for the signal to pass through the capacitor; the lower the frequency, the more difficult it is for current to pass and impossible for DC.

It might mean that the voltage across a capacitor cannot change instantanteously because that would demand an infinite current. The current in a capacitor is C.dV/dt so with a finite current dV/dt must be finite and therefore the voltage cannot have a discontinuity.

Related questions

A capacitor resists a change in voltage. Initially, a capacitor given a DC voltage will appear to have very low resistance, but as current flows and time goes by, the resistance will increase as the voltage approaches the applied voltage. At equilibrium, the voltage across the capacitor will be equal to the applied voltage, the current will be zero, and the resistance will be infinity.

Consider the instantaneous DC analysis. Initially, the capacitor has zero resistance. You apply a voltage and current is controlled by other resistive elements alone. As the capacitor charges, its effective resistance rises. This adds to the net resistance in the circuit, reducing current. At full charge, the capacitor has infinite resistance, so there is no current. Remember that the equation for a capacitor is dv/dt = i/c.

voltage current resistance power inductor capacitor Learning them, you got abc

Voltage = (current) x (resistance) Current = (voltage)/(resistance) Resistance = (voltage)/(current)

Voltage = (current) x (resistance) Current = (voltage)/(resistance) Resistance = (voltage)/(current)

resistance does not produce currents . you need source (like voltage source , current source ,or , discharging capacitor) to generate current .

Voltage = (current) x (resistance) Current = (voltage)/(resistance) Resistance = (voltage)/(current)

because resistance is restricting the current and voltage, so for it be accurate you need to know what the voltage and the amps are.AnswerCapacitance is quite independent of resistance and, therefore, it will NOT vary if resistance is changed.

AC can pass through a capacitor. The higher the frequency of AC the lower the reactance (like resistance). The current and applied voltage are 90 degrees out of phase the current leading the voltage by this amount.

Voltage = Current x Resistance giving us Current = Voltage / Resistance i.e. Voltage divided by resistance

Voltage and current are two different things. Voltage is potential energy per charge, in joules per coulomb, while current is charge transfer rate, in coulombs per second. Its that same as saying that a battery has voltage but no current, because there is no load. Well, a capacitor resists a change in voltage by requiring a current to change the voltage. Once that voltage is achieved, there is infinite resistance to the voltage, and thus no current.

Ohm's Law: Voltage = current x resistance; solving for voltage, current = voltage / resistance.Ohm's Law: Voltage = current x resistance; solving for voltage, current = voltage / resistance.Ohm's Law: Voltage = current x resistance; solving for voltage, current = voltage / resistance.Ohm's Law: Voltage = current x resistance; solving for voltage, current = voltage / resistance.

People also asked