## 9277 #81

wenyang
Posts: 6
Joined: Sun Apr 04, 2010 11:04 pm

### 9277 #81

In the RLC circuit with a driver, I first find a relation between the amplitude and the frequency. Then I take derivative and find the frequency equals to (D) when amplitude is maximized. But ETS gives (C). Anyone knows why?

t2kburl
Posts: 101
Joined: Thu Dec 23, 2010 2:52 pm

### Re: 9277 #81

They are asking for a maximum steady state current amplitude. That implies it has settled to a "natural frequency" or resonance.

Here ... let wikipedia explain it ...
http://en.wikipedia.org/wiki/RLC_circuit
Last edited by t2kburl on Fri Apr 01, 2011 6:21 pm, edited 2 times in total.

WhoaNonstop
Posts: 853
Joined: Mon Sep 21, 2009 1:31 am

### Re: 9277 #81

wenyang wrote:In the RLC circuit with a driver, I first find a relation between the amplitude and the frequency. Then I take derivative and find the frequency equals to (D) when amplitude is maximized. But ETS gives (C). Anyone knows why?
What nationality is this driver?

-Riley

Posts: 81
Joined: Sun Nov 07, 2010 11:37 pm

### Re: 9277 #81

WhoaNonstop wrote:
wenyang wrote:In the RLC circuit with a driver, I first find a relation between the amplitude and the frequency. Then I take derivative and find the frequency equals to (D) when amplitude is maximized. But ETS gives (C). Anyone knows why?
What nationality is this driver?

-Riley
"Step bee-hine my yerrow rine." (San-Francisco bus driver, c. 2011)

wenyang
Posts: 6
Joined: Sun Apr 04, 2010 11:04 pm

### Re: 9277 #81

WhoaNonstop wrote:
wenyang wrote:In the RLC circuit with a driver, I first find a relation between the amplitude and the frequency. Then I take derivative and find the frequency equals to (D) when amplitude is maximized. But ETS gives (C). Anyone knows why?
What nationality is this driver?

-Riley
I am sorry? The driver is just oscillating potential. However, if you are asking literally what nationality is the driver? I have no idea, maybe made in Japan or Germany? lol

wenyang
Posts: 6
Joined: Sun Apr 04, 2010 11:04 pm

### Re: 9277 #81

t2kburl wrote:They are asking for a maximum steady state current amplitude. That implies it has settled to a "natural frequency" or resonance.

Here ... let wikipedia explain it ...
http://en.wikipedia.org/wiki/RLC_circuit
Man, the thing is that I derive the formula and it is (D). If it is (C), then it seems that the resistance has no effect of the amplitude, which is not true. The resistance acts as a damping factor. I bet ETS is wrong.

t2kburl
Posts: 101
Joined: Thu Dec 23, 2010 2:52 pm

R is a constant