In a particular electric circuit, called a low-pass filter, the input voltage V_i is across a resistor and a capacitor, and the output voltage V₀ is across the capacitor (see Fig. 13.28). The voltage gain G (in dB) is given by

Here, ∅ is the phase angle of V₀/V_i. For values of ωT of 0.01, 0.1, 0.3, 1.0, 3.0, 10.0, 30.0, and 100, plot the indicated graphs. These graphs are called a Bode diagram for the circuit.

Calculate values of ∅ (as negative angles) for the given values of ωT and plot a semilogarithmic graph of ∅ vs. ωT

1 G = 20 log1+ (wT) where tan -WT.