(1) 10

70.

Solve for the RC time constant.

(2) 63

R = 69,000 ohms

(3) 90

(4) 100

C =.001 f

t=

69 sec

71.

What is the formula used to compute the RC time constant of any RC circuit?

FORMULA:

t = RC

72.

At this point, we must stress a very important point:

When C is charging, the voltage on C (EC) plus the voltage across R (ER) must

equal Eapp.

100 volts DC are applied to the RC circuit in fig. 8.

At the instant the switch is closed, C starts changing.

In .1 RC time, EC = 10 volts and ER = 90 volts (EC +ER = Eapp).

In 1 RC time, EC = 63 volts and ER = 37 volts (EC + ER = Eapp).

In 2.3 RC time, EC = 90 volts and ER = 10 volts (EC + ER = Eapp).

In 10 RC time, EC = 100 volts and ER = 0 volts (EC + ER= Eapp).

With 150 volts applied to an RC circuit for .1 RC time, EC = 15 volts

and ER =

volts.

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