Question

X1 30 R-50 50 V X-30 0 Figure 13-2 21) If the resistance increases in Figure 13-2, the bandwidth 22) What is the bandwidth of a resonant circuit if its resonant frequency is 14.2 MHz, the inductive reactance is 3.5 kQ and the coil's resistance is 8 ohm? 23) The output voltage of a circuit at 70.7 % of its maximum level measured in dB is: 24) Why does a resistive load increase the bandwidth of a given band-pass filter? 25) For the tuning circuit of a radio frequency receiver, the filter:

Answer 1

Bandwidth of a series RLC circuit = R/L(rads) i.e., BW proportionalto R so if resistance increases the bandwidth increases. 22) f_r = 14.2 MHz (Resonant frequency) X_L = 3.5 k ohm & R = 8 ohm Q - factor = X-L/R = 3.5 k/8 = 437.5 BW = f_r/Q = 14.2 MHZ/437.5 = 32.46 KHz (23) 70.7% of maximum = 0.707 of its maximum voltage 0.707 of its max. in dB = 20 log(0.707) = -3 dB. (24) As the BW proportionalto R thus the resistive Load increases the Bandwidth, of the given BPF.