some basic questions about circuits theory

[INS-ANI]

some basic questions

I have few problems of network theory, i will really appreciate if any one can help me with concepts.(I will add diagram wherever is needed)

1) A resistance coil posses residual self inductance and capacitance apart from resistance. taking into consideration all three, the impedance across the coil is what?
(Please just explain me the orientation of R,L and C i.e will they will in parallel or series or a combination of parallel and series.what is the equivalent circuit of a coil? and the reason behind the same).

2) A parallel RLC ckt has a response current I(L)=2e^(-5t)-5e^(-10t) in the inductor of value L=0.2H. the values of C and R are?

 

[Braski]

Re: some basic questions

1) dunno

2) the solving need some calculus in Laplace domain. Apply inverse transformation to your I(L)...
i think it gives: IL(s)=2/(s+5)-5/(s+10). VL(S)=Ls*IL(S)...
so you have the voltage on your parallel impedance...uhm now i don't know how to go on...it seems some data missed. R and C can't be determined only with current in L and L value. Attach other data. With this data, you can determine voltage across the parallel impedance, but no other (i think so).

 

[INS-ANI]

For the q2, no other data is provided. I have tried to calculate voltage across L and equate the vol to vol across cap and resistor.
so VL(s)=Vc(s)=(1/c)(integration of Ic(s))=(1/c)(i(s)/s)

even i am stuck at this point on how to calculate Ic.

I have tried KCL as well, but not good!

 

[svhb]

For q1:

The windings of the solenoid have a resistance, so this comes in series with the inductor. The capacitance is distributed across the windings. If you consider a single layer of turns, it stays easy, multiple layers of turns have more capacitors that span multiple turns. See attachment.

For q2:

The equation is given is the solenoid current in a response to what? A voltage step? An impulse? A step of 1Volt or 100Volt?

Since your current is not zero at time zero, I think the only possible input is a Dirac function. (Impulse response).


Stefaan