Hi I'm suppose to analyze the circuit shown below
and for preliminary calculations I'm suppose to find what value of R would give me under-damped and over-damped.
For lab we were assigned to use 6.8k ohm and a 560 ohm resistor for R. I used pspice to simulate the circuit. I got under-damped for 6.8k ohm for R and over-damped for 560 ohm for R.
For the preliminary calculations, my first step was to find the second order.
(LC)i'' + (L/R)i' + i = f(t)/R
Givens: L = 68mH, C=.01uF
After substituting the values for L and C my characteristic equation was
m^2 + [(1E8)/R]m + 1.47E9 = 0
a = 1
b = (1E8)/R
c = 1.47E9
b^2-4ac > 0 is over-damped
b^2-4ac < 0 is under-damped
[(1E8)/R]^2 - 4(1)(1.47E9)
I'm not sure if I'm doing this correctly. I just assumed that if I were to isolate R from b^2-4ac and get something like R > # or R < #, then I found the resistant values that I can use that would give me under-damped or over-damped. So I got R > 1304, R<1304 which is way off from the pspice simulation. Any ideas? Thanks in advance.
and for preliminary calculations I'm suppose to find what value of R would give me under-damped and over-damped.
For lab we were assigned to use 6.8k ohm and a 560 ohm resistor for R. I used pspice to simulate the circuit. I got under-damped for 6.8k ohm for R and over-damped for 560 ohm for R.
For the preliminary calculations, my first step was to find the second order.
(LC)i'' + (L/R)i' + i = f(t)/R
Givens: L = 68mH, C=.01uF
After substituting the values for L and C my characteristic equation was
m^2 + [(1E8)/R]m + 1.47E9 = 0
a = 1
b = (1E8)/R
c = 1.47E9
b^2-4ac > 0 is over-damped
b^2-4ac < 0 is under-damped
[(1E8)/R]^2 - 4(1)(1.47E9)
I'm not sure if I'm doing this correctly. I just assumed that if I were to isolate R from b^2-4ac and get something like R > # or R < #, then I found the resistant values that I can use that would give me under-damped or over-damped. So I got R > 1304, R<1304 which is way off from the pspice simulation. Any ideas? Thanks in advance.