Question

4. An electrical filter circuit is built with a series resistor (R), inductor (L) and capacitor (C). The ratio of resistor voltage (output) to source voltage (input) is given by H is the magnitude of a complex number, where ZL=JwL ZC = 1 / (j w C) andjsVT (same as 1) w frequency (radians/sec) 2 f,where f is frequency in Hz. For each exercise, assign the values of R, L and C and set the recommended frequency range. Then have MATLAB do the complex number calculations using the abs () function to calculate the magnitudes. Finally, plot H as a function of f in Hz. As a check of your results, note that the peak value of H corresponds to Also, the range of w for which H 1 / V2 = 0.707 is called the bandwidth. For this circuit, the bandwidth in radians/sec. is equal to R/ L (a) R=1000, L = 0.01 and C = 10-6 w 100 to 106 in steps of 100 rad./s. (b) Repeat (a) changing only the frequency to a logarithmic scale on your plot. Comment on the advantage of the logarithmic scale and whether the bandwidth is as expected.

Answer 1

R=1000;
L=.01;
C=10^-6;
w=100:100:10^6;
ZL=1j*w*L;
ZC=1./(1j*w*C);
H=abs(R./(R+ZL+ZC));
%a
plot(w,H)
%b
figure
semilogx(w,H)

R = 1000: L = .01: C = 10^-6: W = 100: 100: 10^6: ZL = 1j times W times L: H = abs (R./(R + ZL + ZC)): %a plot (w, H) %b figure semilog x (w, H)