(c)
The current has its largest value
when
so
The graphs are of the same form as in Figures 19.33a and b in the textbook.
Reflect:
The maximum charge on the capacitor does not depend on the resistance. The initial current is the same as
the current produced when the resistor alone is connected to the battery.
19.68.
Set Up:
The time constant is
so
and
Solve: (a)
gives
Three time constants
are required.
(b)
so
19.69.
Set Up:
After a long time the current has dropped to zero, there is no potential drop across the
resistor and the full battery voltage is applied to the capacitor network. Just after the switch is closed the charge and
voltage across each capacitor is zero and the battery voltage equals the voltage drop across the resistor. The time
constant is
where
C
is the equivalent capacitance of the network.
Solve: (a)
The 20.0 pF, 30.0 pF and 40.0 pF capacitors are in series and their equivalent capacitance
is given by
After a long time the voltage across the 10.0 pF capacitor is 50.0 V. The charge on this capacitor is
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '07
 Shoberg
 Current, Resistance, Electric charge, Electrical resistance, PF, DirectCurrent Circuits

Click to edit the document details