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D.A.S.
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You neglected the input impedance Zin of the base to Re, as Zin = hFE*Re =~ 47k which is lowering the base bias. That's all.

Don't worry about hFE =100 unless you expect a 5% tolerance of Vc=Vcc/2 .there are better ways with negative feedback.

So what should 15k be increased to ? So that the effect in parallel with 47k results is 15k , as you intended.

To get Ic=mA, you must have Vbe= 600 mV to start with then add Re=470 mV you get around Vb=1V not 1.17

consider re is 26/Ic so for 1mA and subtract from Re. It would use 420 in this circuit and reduce 15k to 14k to get 1.0V on Vb.

But an NFB circuit is better.

You neglected the input impedance Zin of the base to Re, as Zin = hFE*Re =~ 47k which is lowering the base bias. That's all.

Don't worry about hFE =100 unless you expect a 5% tolerance of Vc=Vcc/2 .there are better ways with negative feedback.

So what should 15k be increased to ? So that the effect in parallel with 47k results is 15k , as you intended.

You neglected the input impedance Zin of the base to Re, as Zin = hFE*Re =~ 47k which is lowering the base bias. That's all.

Don't worry about hFE =100 unless you expect a 5% tolerance of Vc=Vcc/2 .there are better ways with negative feedback.

So what should 15k be increased to ? So that the effect in parallel with 47k results is 15k , as you intended.

To get Ic=mA, you must have Vbe= 600 mV to start with then add Re=470 mV you get around Vb=1V not 1.17

consider re is 26/Ic so for 1mA and subtract from Re. It would use 420 in this circuit and reduce 15k to 14k to get 1.0V on Vb.

But an NFB circuit is better.

Source Link
D.A.S.
  • 148k
  • 3
  • 56
  • 190

You neglected the input impedance Zin of the base to Re, as Zin = hFE*Re =~ 47k which is lowering the base bias. That's all.

Don't worry about hFE =100 unless you expect a 5% tolerance of Vc=Vcc/2 .there are better ways with negative feedback.

So what should 15k be increased to ? So that the effect in parallel with 47k results is 15k , as you intended.