Question

4.19

how to.solve it?

4.17. A transistor gives a transconductance collector c of 1/13 Ω with base-emitter voltage of 800 mV. Calculate the value of Is of the transistor where a i the small still equa 4.18. Determine the operating point and e small-signal oolin : 4.57. 4.22. The coll of the circuits shown in Fig. 4.57. Assume Is -8x10-10 A, β 100, and 4.19. Determine the operating point and the small-signal model of Q1 for each of varies fr voltage age is curren Rc 50Ω

Answer 1

Given v_A = Infinity, implies r_c = infinity, I_s = 8 times 10^-16 A, beta = 100 v_cc = 2v As we know that I_c = beta I_B = 100 times mu A implies I_C = 1 MA V_BE = V_t ln (I_L/I_S) [because i = i_s e^v_BE/nVT] small signal model = 26 mv ln (10^-3/8 times 10^-11) v_BE = 724 mv At th - output loop, -v_cc + I_ER_E + V_CE = 0 v_CE = v_cc - I_ER_E TildeEqual v_cc - I_c R_E = Z - 1K times 1 ma v_CE = 1v We know that g_m = I_C/V_T = 1 mA/26 mv implies g_m = 1/26 ohm \r\n As we know, beta = g_m r_pi r_pi = beta/g_m = 100/1/26 r_pi = 2.6 k ohm small signal model -v_cc + v_bE + RI_S exp (v_BE/V_T) = 0 [because I_C TildeEqual I_E = I_s exp (v_BE/v_T)] Z = V_BE + 8 times 10^-3 exp (v_BE/26 mv) v_BE = 730 mv \r\n Apply KVL