RC time constant...

Thread Starter

i3ill

Joined Dec 7, 2008
1
Doing some homework for my basic DC electronics class and do not know how to answer this question!
The RC time constant of a circuit consisting of a 10k resistor in series with a 50 uF capacitor is _______. When a power supply is connected to this RC circuit, it is generally considered that the capacitor will be fully charged in ________ time constants, which would be ________ seconds.

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Wendy

Joined Mar 24, 2008
23,415
Concerning the 1st problem, this is one of those rare situations the description is also the equation.
 

Wendy

Joined Mar 24, 2008
23,415
I just reviewed the chapter, it doesn't give the answer for the 2nd question. I remember the answer from my school days. Till the OP gets the first problem I'm not too worried about it though.
 

TanTJ

Joined Mar 6, 2008
21
I'm pretty sure I know the answer as well, but don't want to give it away. Is the answer to the second part of the question the derivative of the function f(x)=5x+7? If you get my meaning :)
 

jpanhalt

Joined Jan 18, 2008
11,087
Isn't the second part like similar questions related to any rate equation? That is, what do you consider fully charged, reacted, or whatever: 86%, 95%, 99%, etc? The answer will be what the instructor told you. The exponent is usually 3, 4, or 5 for practical purposes. I tend to prefer 4 or even 3, if the time constant is long; although, some people stick rididly to 5 (99%).

John
 
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