- #1

EvLer

- 458

- 0

Hello,

now we are in phasors and I am missing something in this problem:

given a circuit of indep current source (5cos(wt)), R, L (with vL(t)) all in series, no values for them,

although voltage across inductor vL(t) = 3cos(wt + theta), we need to find theta.

So, by using impedance for L: Z = jwL, vL(t) = Z*I,

so I got vL(t) = jwL5 /_ 0 which is also = 3/_theta

And now what? The answer is 90 degrees, but how do I get it?

Thanks a lot.

now we are in phasors and I am missing something in this problem:

given a circuit of indep current source (5cos(wt)), R, L (with vL(t)) all in series, no values for them,

although voltage across inductor vL(t) = 3cos(wt + theta), we need to find theta.

So, by using impedance for L: Z = jwL, vL(t) = Z*I,

so I got vL(t) = jwL5 /_ 0 which is also = 3/_theta

And now what? The answer is 90 degrees, but how do I get it?

Thanks a lot.

Last edited: