Hi once more...
I was trying to calculate Ic, Ib, Ie and Vce to the attached circuit, but my math is not matching the LTSpice simulation.
I have tried to simplify the circuit eliminating the Base Voltage Source and Base Resistor and replacing the Zener by a Voltage Source with the same value but looks like it's not the same thing because LTSpice is not showing the same results...
Can anyone help me finding what am I doing wrong here?
PS: I'm writing now my calculations!
I'll put them here in a bit!
By the mesh's laws:
Vcc = RcIc + D1 + Vce + ReIe
Zener  Vbe ReIe = 0
Ic = βIb
Note: Ie = (β+1)Ic/β and i have assumed that the voltage drop at the LED is 0.7.
12 = 100Ic + 0.7 + Vce + 220(257/256)Ic
5.6  0.7  Re 220(257/256)Ic = 0
Ic = 256Ib
Ic = 0.02218A
Vce = 4.181V
Ib = 0.0000867A
I was trying to calculate Ic, Ib, Ie and Vce to the attached circuit, but my math is not matching the LTSpice simulation.
I have tried to simplify the circuit eliminating the Base Voltage Source and Base Resistor and replacing the Zener by a Voltage Source with the same value but looks like it's not the same thing because LTSpice is not showing the same results...
Can anyone help me finding what am I doing wrong here?
PS: I'm writing now my calculations!
I'll put them here in a bit!
By the mesh's laws:
Vcc = RcIc + D1 + Vce + ReIe
Zener  Vbe ReIe = 0
Ic = βIb
Note: Ie = (β+1)Ic/β and i have assumed that the voltage drop at the LED is 0.7.
12 = 100Ic + 0.7 + Vce + 220(257/256)Ic
5.6  0.7  Re 220(257/256)Ic = 0
Ic = 256Ib
Ic = 0.02218A
Vce = 4.181V
Ib = 0.0000867A
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