Chapter 4 problems: Difference between revisions

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(New page: ===4.20=== ===4.34=== ===4.45=== ===4.64===)
 
 
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===4.20===
===4.20===
*We want to establish a DC operating point for the BJT. Writing a loop equation gives us -V<sub>BB</sub>-V<sub>in</sub>(t)+i<sub>B</sub>R<sub>B</sub>+v<sub>BE</sub>=0. To form a load line, we will let v<sub>in</sub>(t)=0 & i<sub>B</sub>=0. Thus v<sub>BE</sub>=V<sub>BB</sub>+v<sub>in</sub>(t) and i<sub>B</sub>(t)=(V<sub>BB</sub>+v<sub>in</sub>(t))/R<sub>B</sub>
:*<math>V_{in}=-0.2, 0, 0.2</math> for the minimum, Q-point and maximum values.

:{| class="wikitable" border="1" align="center"
|+
! <math>v_{in}</math> V!! <math>V_{BE} </math> V!! <math>i_B</math> uA
|-
| -.2|| .45 || 2
|-
| 0|| .58 || 5
|-
| .2 || .62 || 10
|}

*Writing a loop equation for the output: <math>-V_{CC}+R_CI_C+V_{CE}=0</math>.
:{| class="wikitable" border="1" align="center"
|+
! <math>v_{in}</math> V!! <math>V_{CE}</math> V !! <math>i_C</math> mA
|-
| -.2|| 19 || .8
|-
| 0|| 16|| 2
|-
| .2 || 12 || 4
|}

*<math>A_v \cong (19-12)/.4=12.5</math>

===4.34===
===4.34===
===4.45===
===4.45===

Latest revision as of 12:36, 5 March 2010

4.20

  • We want to establish a DC operating point for the BJT. Writing a loop equation gives us -VBB-Vin(t)+iBRB+vBE=0. To form a load line, we will let vin(t)=0 & iB=0. Thus vBE=VBB+vin(t) and iB(t)=(VBB+vin(t))/RB
  • for the minimum, Q-point and maximum values.
V V uA
-.2 .45 2
0 .58 5
.2 .62 10
  • Writing a loop equation for the output: .
V V mA
-.2 19 .8
0 16 2
.2 12 4

4.34

4.45

4.64