Hello, currently I try to teach myself the basics of analog circuits. Actually I already had to attend a circuitry course at university, but it's already some time ago and I didn't learn as much as I anticipated. It was mostly about circuit analysis and small signal models, no circuit synthesis.
For this purpose, I've bought the book "Art of Electronics, 3rd Edition". However I am having some trouble to comprehend the design example for the differential amplifier on page 103. I've attached the schematic , if you don't have access to this book(please scroll to the second page, somehow latex wants a blank page first).
The following formulas are derived:
G_diff = v_out / (v_1 - v_2) = R_C / (2 * (R_E + r_e))
G_CM = - R_C / (2 * R_1 + R_E + r_e)
CMRR is approximately = R_1 / (R_E + r_e)
The author writes, he wants the following things:
1) V_out = 0.5 * V_cc
2) Quiescent current of 100µA through R_C.
==> R_C = 2.5 V / (100µA) = 25 kOhm ==> I can totally follow that.
3) R_1 is chosen to give total emitter current of 200µA, split equally between both sides.
My Questions:
A) How is R_E calcualted?
B) How is R_1 calculated?
My thoughts to R_1:
I_{R_1} = 200µA
U_{R_1} = V_out - V_{CE,2} - V_{R_1} + V_EE = 2.5V - V_{CE,2} - V_{R_1} + 5V = ???
R_1 = U_{R_1} / I_{R_1} = ???
My thoughts to R_E:
I_{R_E} = 100µA
U_{R_E} = V_out - V_{CE,2} - V_{R_1} + V_EE = 2.5V - V_{CE,2} - V_{R_1} + 5V = ???
R_E = U_{R_E} / I_{R_E}
In the exercise 2.18 on the next page I am supposed to design a differential amplifier on my own, but I can't do that if I do not even understand the example.
Kind regards
For this purpose, I've bought the book "Art of Electronics, 3rd Edition". However I am having some trouble to comprehend the design example for the differential amplifier on page 103. I've attached the schematic , if you don't have access to this book(please scroll to the second page, somehow latex wants a blank page first).
The following formulas are derived:
G_diff = v_out / (v_1 - v_2) = R_C / (2 * (R_E + r_e))
G_CM = - R_C / (2 * R_1 + R_E + r_e)
CMRR is approximately = R_1 / (R_E + r_e)
The author writes, he wants the following things:
1) V_out = 0.5 * V_cc
2) Quiescent current of 100µA through R_C.
==> R_C = 2.5 V / (100µA) = 25 kOhm ==> I can totally follow that.
3) R_1 is chosen to give total emitter current of 200µA, split equally between both sides.
My Questions:
A) How is R_E calcualted?
B) How is R_1 calculated?
My thoughts to R_1:
I_{R_1} = 200µA
U_{R_1} = V_out - V_{CE,2} - V_{R_1} + V_EE = 2.5V - V_{CE,2} - V_{R_1} + 5V = ???
R_1 = U_{R_1} / I_{R_1} = ???
My thoughts to R_E:
I_{R_E} = 100µA
U_{R_E} = V_out - V_{CE,2} - V_{R_1} + V_EE = 2.5V - V_{CE,2} - V_{R_1} + 5V = ???
R_E = U_{R_E} / I_{R_E}
In the exercise 2.18 on the next page I am supposed to design a differential amplifier on my own, but I can't do that if I do not even understand the example.
Kind regards
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