Question

Class C power amplifier calculation

(c) A Class C power amplifier shown in Figure-Q4 has a base bias voltage V" = -5V and Vcc = 30V. It is determined that a peak value of 9.8V at 1MHz is required to drive the transistor to its saturation current of 1.8A. Further let the ratio, peak value of the fundamental component to the peak value of the output waveform be approximated by (-0.0072贍+ 4.1e-3.54) × 10-3 where 0c is the conduction angle Veo ic RFC Voo Figure-04 i. Calculate the base voltage required to drive the transistor to saturation. ii Hence determine the conduction angle. iWhat is the output power at IMHz? (2Marks) (3Marks) 3Marks) (4Marks) Calculate the efficiency

Answer 1

"Given: V_BB = -5v v_cc = 30v peak value of input = v_p = 9.8 v at 1mAz rightarrow to drive the transistor to saturation. Let r_1 be the ratio, peak value of the fundamental to the peak value of output waveform. It is given as: r_1 = (-0.0072 Q^2_c + 4.1 theta c - 3.54) times 10^-3 theta_c = conduction angle, i) The base voltage required to drive the transistor to saturation i.e, v_c, the i/P voltage at which transistor begin to conduct V_c =