How much time does it take a fully charged 500 microfarad capacitor, connected in series with a 20K ohm resistor across a 15v supply, to discharge its current to 0.5 milliamps? I have tried to solve this problem for quite a few days and have come to realize there is basic principle operation of capacitors in dc circuits which I am simply not getting. So far my best effort answer is 18.97 sec. Is this correct?
Calculus of A Discharging Capacitor
- Thread starter Larry Makanza
- Start date
Try the information in our Ebook - http://www.allaboutcircuits.com/vol_1/chpt_13/2.html
Use this equation:
ic=(Vo/R)*exp(-t/(RC))
where:
ic=instantaneous capacitor current (A)
Vo=initial voltage of the capacitor (V)
R=resistance of the resistor (Ω)
C=capacitance (F)
This equation can be derived by using the basic equation ic=C*dv/dt and first order differential equations.
ic=(Vo/R)*exp(-t/(RC))
where:
ic=instantaneous capacitor current (A)
Vo=initial voltage of the capacitor (V)
R=resistance of the resistor (Ω)
C=capacitance (F)
This equation can be derived by using the basic equation ic=C*dv/dt and first order differential equations.
