Consider the single - supply bias network shown in Fig. 6. 60(a). Provide a desi
ID: 1804099 • Letter: C
Question
Consider the single - supply bias network shown in Fig. 6. 60(a). Provide a design using a 9 - V supply in which the supply voltage is equally split between RC, VCE, and RE with a collector current of 0. 6 mA. The transistor beta is specified to have a minimum value of 90. Use a voltage divider current of IE/10. or slightly higher. Since a reasonable design should operate for the best transistors for which beta is very high, do your initial design with beta = infinity . Then choose suitable 5% resistors (see Appendix H). making the choice in a way that will result in a VCB that is slightly higher than the ideal value. Specify the values you have chosen for RE , RC, R1, and R2. Now, find VB, VE, , VC, and Ic for your final design using beta = 90.Explanation / Answer
=, IB=0, VB=VE+0.7 V=3.7 V, IEIC=0.0006 A, IR1=IE/10=0.00006 A
R1=(9-3.7)/0.0000688,333.33 , R2=3.7/0.00006=61,666.67
use R1=82,000 , R2=61,700 , VBB=9*68,000/(82,000+68,000)4.08 V
RBB=68,000*82,000/150,00037,173.33 , RE=RC=3 V/0.0006 A=5,000
use 5,100 , =90, IE=(VBB-0.7)/(RBB/(+1)+RE)=
(4.08-0.7)/(37,173.33/((90+1)+5100)0.0006136 A
VE=0.0006136*51003.13 V
VB=VE+0.7=3.83 V
VC=9-5100*0.0006*90/915.97 V