Question

[25pt] Find the voltages at all nodes and the currents through all branches in the circuit below. Assume lrE|-0.7V and β 0. +20V +20V +20V IKL

Answer 1

beta = infinity, V_BE = 0.7 V lets start from I_4 V_I = 0 V (grounded) v_g - V_I = 0.1 V ( Vertical-bar V_BE Vertical-bar = 0.7 V) = > V_9 = 0.7 V V_H = V_g = 0.1 V I_H = 20 - H_V/2 = 20 - 0.7/2 = 9.65 I_H = 4.65 mA \r\n As beta = infinity I_g = 0 I_I = I_H = 4.65 mA (as I_g = 0 & I_I = I_H + I_g) V_f = 0 V (grounded) V_D = 20 V (given) V-D - V_C = 0.7 (as Vertical-bar V_ae Vertical-bar = 0.7 v) V_c = 19.3 V (they are shared circuit) V_E = V_c = 19.3 V V_A = 20 V (given) we know V-CB almostequalto 0.4 V (for active transistor) So V_C - V_B = 0.4 V V_B = V_c - 0.4 = 19.3 - 0.4 V_B almostequalto 18.9 V I_B = 18.9 - 0/1 k Ohm = 18.9 mA \r\n I_B = 18.89 mA