Question

results to verify your design. 2. For the circuit in Figure 2 calculate and select standard value resistors for R1, R2, Rc and RE So that Vc= .5*Vcc volts and Ic = 1.0 mA (± 10%) X Photos -figure 2.PNG RC ŞRb1 2N3904 15V _ SRb2 SRE Figure 2: Common Emitter Stiff Bias Reference Circuit

Answer 1

For I_C = 1 mA, B = 80 V_B = RB_2/RB_2 times RB_1 times V_1 equation (1) is RB_2/RB_2 + RB_1 times V_1 - IB times (RB_1 RB_2/RB_1 + RB_2) - 0.7 - I_E R_E = 0 equation (2) is 15 - I_c R_c - V_CE - I_E R_E = 0 15 - I_C RC - 15/2 = 0 RC = 15/2/1 mA = 7.5 k ohm {as V_c = V_CE + I_E R_E} for V_CE = 1V rightarrow I_E middot R_E = 6.5 V gives RE = 6.5/81/80 times I_C = 6.4197 k ohm \r\n From (1) (RB_2/RB_2 + RB_1) times 15 - 1 times 10^-3/20 (RB_1 RB_2/RB_1 + RB_2) -0.7 - 81/80 times R_E = 0 (RB_2/RB_2 + RB_1)15 - 1 times 10^-3/80 (RB_1 RB_2/RB_1 + RB_2) = 7.2 Let RB_2 = 10 k ohm 10 kl times 15/10 kl + RB_1 - 1 times 10^-3/80 times 10 times 10^3 times RB_1/RB_1 + 10 k ohm = 7.2 15 times 10 k ohm/10 k ohm + RB_1