well to get the answer first know the principle by which a capacitor(consider a capacitor without dielectric) gets charged .let a capacitor with plates p1 and p2 and resistor in parlell are connected to a DC source , when the switch is closed the circuit is in ON state and current starts flowing ,assume the flow of current as the movement of negative charges then the concept would be much clear.
assume that p1 is connected with positive terminal of the battery and p2 with the negative terminal ,now as the switch is closed the negative charge on p1 is attracted by the positive terminal of the battery and is driven to the other plate p2 of capacitor.as this process continues charge seperation increases and potential difference starts getting developed and after a very long time the potential diff. across capacitor becomes equal to the applied voltage V.
the maximum charge is Q0=CV
and charge at any time is , Q(t)=Q0(1-e^(-t/T))
where T=time constant of the circuit
R resistor C capacitance will shift phase since the capacitor will take time to charge.
It increases. The time constant of a simple RC circuit is RC, resistance times capacitance. That is the length of time it will take for the capacitor voltage to reach about 63% of a delta step change. Ratio-metrically, if you double the resistance, you will double the charge or discharge time.
The time it takes to fully charge a capacitor depends on the capacitance and resistance of the circuit; the voltage is irrelevant. The equation you need is:t = 5RCwhere: t = time in seconds, R= resistance in ohms, and C =capacitance in farads.So you should now be able to calculate the time for yourself, but remember to convert the resistance into ohms and the capacitance into farads before you insert the figures into the equation.
T=RC T=Time Constant R=Resistance in ohms C= Capacitance in Farads
an oscillating RC circuit
Answer : increase The time required to charge a capacitor to 63 percent (actually 63.2 percent) of full charge or to discharge it to 37 percent (actually 36.8 percent) of its initial voltage is known as the TIME CONSTANT (TC) of the circuit. Figure 3-11. - RC time constant. The value of the time constant in seconds is equal to the product of the circuit resistance in ohms and the circuit capacitance in farads. The value of one time constant is expressed mathematically as t = RC.
R resistor C capacitance will shift phase since the capacitor will take time to charge.
In an RC circuit the time constant is found by R x C. T = R x C to be precise.It is the time required to charge the capacitor through the resistor, to 63.2 (≈ 63) percent of full charge; or to discharge it to 36.8 (≈ 37) percent of its initial voltage. These values are derived from the mathematical constant e, specifically 1 − e − 1 and e − 1 respectively.
Increased The time constant of an "RC" circuit IS RC. So it's directly proportional to 'R' and also directly proportional to 'C'.
It increases. The time constant of a simple RC circuit is RC, resistance times capacitance. That is the length of time it will take for the capacitor voltage to reach about 63% of a delta step change. Ratio-metrically, if you double the resistance, you will double the charge or discharge time.
Equation for voltage across capacitor in series RC circuit is as follow, vc = V(1-e-t/RC) V = DC voltage source. So theoretically time taken for capacitor to charge up to V volt is INFINITY. But practically we assume 95% or 98% of source voltage as fully charge. RC is the time constant which is the time take for capacitor to charge 63%. In this case time constant is 500uF*2.7Kohm = 1.3sec Time taken to charge 95% = 3*T = 3*1.3 = 3.9sec T = time constant Time taken to charge 98% = 4*T = 4*1.3 = 5.2sec
If a resistor is connected in series with the capacitor forming an RC circuit, the capacitor will charge up gradually through the resistor until the voltage across the capacitor reaches that of the supply voltage. The time called the transient response, required for this to occur is equivalent to about5 time constantsor5T. This transient response timeT, is measured in terms ofτ= R x C, in seconds, whereRis the value of the resistor in ohms andCis the value of the capacitor in Farads. This then forms the basis of an RC charging circuit were5Tcan also be thought of as"5 x RC".
An RC circuit with a time constant of 3.6s will take 5 time constants, or about 18 seconds to fully discharge a capcaitor.Theoretically, the capacitor will never discharge, because an RC circuit is logarithmic, but 5 time constants is the generally accepted time to discharge to less than 1% of initial voltage.
In both cases, the time constant of the RC circuit is increased. If the application is a high- or low-pass circuit, then the filter cutoff frequency is decreased in both cases. If the application is a phase-shift network, then the frequency for a given phase- shift is reduced.
The resistor allows a slow charge to enter the capacitor. When this charge reaches a certain point the circuit activates and forces the capacitor to discharge. Once discharged the circuit reverses itself and starts the charge over again. The larger the cap and/or resistor the lower the frequency because it takes longer to charge the cap.
30-50 min
It's the product of ' R ' times ' C '.