x2+ax+b=0|a=2sx2+2sx+s2=s2−b(x+s)2=s2−b
x+s=√s2−bx=−s±√s2−b|s=a2x=−a2±√(a2)2−b
[Eop]
x2+ax+b=0|a=2sx2+2sx+s2=s2−b(x+s)2=s2−b
x+s=√s2−bx=−s±√s2−b|s=a2x=−a2±√(a2)2−b
[Eop]
an arbitrary output range ver. of the below a related post + the formulas for the non supply median centered output limit :
IC=VLR3 ⇒ R3=VLIC , def. : χ=R3(1VL−1VH){VH=VSR1R1+R2=VS11+R2R1VL=VSR1||R3R1||R3+R2=VS11+R2R1||R3=VS11+R2R1(1+R1R3)
{VHVS(1+R2R1)=1 ⇒ R2R1=VSVH−1 ... =VSVL−1R1R3+1VLVS(1+R2R1(1+R1R3))=1 ⇒ R2R1(R1R3+1)=VSVL−1 ⇒ R1R3=VSVL−1VSVH−1−1 ⇒
⇒ R1=R3(VSVL−1VSVH−1−1)=R311VH−1VS(1VL−1VH)=χ⋅11VH−1VS
R2=R1(VSVL−1)=R3(VSVL−1)(VSVL−1VSVH−1−1)==R3(VSVL−1−VSVH+1)=R3VS(1VL−1VH)=R2=χ⋅VS
---==≡==--- Do NOT mix the formulas from the above with the formulas from the below ---==≡==---
• a Supply median centered output limit ver. -- Some definitions :
VS=VCCIC=ISNKVH=R1R1+R2VL=R1||R3R1||R3+R2IC=VLR3⇒R3=VLIC=VSIC⋅1−1n2
R2R1=α=VLVH=n−1n+1=R1||R3R2=(R1R3R1+R3)R2=1√1+R1R3 ⇒⇒ R1=R3(1α2−1)=R34n(n−1)2⇒ R2=α⋅R1=R34nn2−1
• (↑ You only need to provide VS , n , IC ↑ , anyway - ) Some more definitions :
VL=VS−VH , 1n - is the dynamic output-range around the supply median --e.g.-- the 1 n-th of the total supply
{VH−VLVS=1n=R1R1+R2−R1||R3R1||R3+R2=11+R2R1−11+R2R1||R3VH+VL=VS ⇒⇒⇒1=11+R2R1+11+R2R1||R3
{1+1n2=11+R2R1=A⇒R1A=R1+R21−1n2=11+R2R1||R3=B⇒R1||R3B=R1||R3+R2R1||R3=11R1+1R3=R1⋅R3R1+R3
R2=R1(1A−1)=R1n−1n+1==R1||R3(1B−1)=R1R3R1+R3⋅n+1n−1⇒R2=√R12R3R1+R3=R1√1+R1R3
• More backwards extending definitions :
{1A−1=2nn+1−1=n−1n+1=α1B−1=2nn−1−1=n+1n−1=1α{VH−VL=VSnVH+VL=VS⇒{VH=VS1+1n2VL=VS1−1n2
{VL=VSR1||R3R1||R3+R2=VS1+R2R1||R3=VS1+1α=αVS1+αVH=VSR1R1+R2=VS1+R2R1=VS1+α⇒VLVH=α
• About αFn.of(n) :
{VH−VL=VSnVH+VL=VS⇒{1−α=1n⋅VSVH1+α=VSVH⇒n(1−α)=1+αn=1+α1−α
n−nα=1+αn−1=α(n+1)α=n−1n+1
[Eop]
about (scheduled) :: every now and then (not too often) i set myself to re-figure it out (the history has proven there exists a variance of what i come up with each time ...)
... so -- Def.-s , etc. ... ::
(x−a)(x−b)=0 x2−(a−b)x+ab=0 x2+px+q=0→x2+2px+p2=px−q+p2 |×3x2−2px+p2=−3px−q+p2 |+ ↑4x2+4px+4p2=0−4q+4p2 |−3p24x2+4px+p2=p2−4q |÷4x2+2p2x+(p2)2=(p2)2−q x2+2p2x+(p2)2=(p2)2−q(x+p2)2=(p2)2−qx=−p2±√(p2)2−q
... (it) came out double ((at) this time) -- the short and the long -- way to (the solution) F;T
// is likely ↑↑ why ↑↑ in many blogs folks do not get a thing what i say
// (as an old school programmer i always live-compact my code(read: text))
see also the inner properties of @ About the Quadratic Equation
[Eop]
Va=VS+(Vp−VS)RgRg+RS
Def : 1RX=1Rg+RS+1RP==Rg+RS+RP(Rg+RS)RP
Vn=VZ+(VO−VZ)RXRX+Rf
Vp=VS+(VR−VS)RXRX+Rf
V_b=V_Z+\left[{\cancel{V_Z}+\left({V_O-V_Z}\right)\frac{R_X}{R_X+R_f}\cancel{-V_Z}}\right]\frac{R_g}{R_g+R_S}=V_Z+\left({V_O-V_Z}\right)\frac{R_X}{R_X+R_f}·\frac{R_g}{R_g+R_S}
V_a=V_S+\left[{\cancel{V_S}+\left({V_R-V_S}\right)\frac{R_X}{R_X+R_f}\cancel{-V_S}}\right]\frac{R_g}{R_g+R_S}=V_S+\left({V_R-V_S}\right)\frac{R_X}{R_X+R_f}·\frac{R_g}{R_g+R_S}
V_S-V_Z=\left({V_O-V_R+V_S-V_Z}\right)\frac{R_X}{R_X+R_f}·\frac{R_g}{R_g+R_S}
\boxed{\quad A_V\quad}=\frac{V_O-V_R}{V_S-V_Z}=\left({1+\frac{R_f}{R_X}}\right)\left({1+\frac{R_S}{R_g}}\right)-1=\cancel{1}+\frac{R_f}{R_X}+\frac{R_S}{R_g}+\frac{R_fR_S}{R_XR_g}\cancel{-1}=
=\frac{R_gR_f+R_XR_S}{R_XR_g}+\frac{R_fR_S}{R_XR_g}=\frac{R_fR_S}{R_XR_g}\left({\frac{R_g}{R_S}+\frac{R_X}{R_f}+1}\right)=
=\frac{R_fR_S}{R_g}·\frac{R_g+R_S+R_P}{\left({R_g+R_S}\right)R_P}\left({\frac{R_g}{R_S}+1+\frac1{R_f}·\frac{\left({R_g+R_S}\right)R_P}{R_g+R_S+R_P}}\right)=
=R_f·\frac{R_S}{R_g}\left({\frac1{R_P}+\frac1{R_g+R_S}}\right)\left({\frac{R_g+R_S}{R_S}+\frac1{R_f}·\frac1{\frac1{R_P}+\frac1{R_g+R_S}}}\right)=
=R_f\left({\frac1{R_P}+\frac1{R_g+R_S}}\right)\frac{R_g+R_S}{R_g}+\frac{R_S}{R_g}=\boxed{\quad\frac1{R_g}\left[{R_f\left({\frac{R_g+R_S}{R_P}+1}\right)+R_S}\right]\quad}=
=R_f\left({\frac{1+\frac{R_S}{R_g}}{R_P}+\frac1{R_g}}\right)+\frac{R_S}{R_g}
\frac{A_V-\frac{R_S}{R_g}}{R_f}-\frac1{R_g}=\frac{1+\frac{R_S}{R_g}}{R_P}
\boxed{\quad R_P\quad}=\frac{1+\frac{R_S}{R_g}}{\frac{A_V-\frac{R_S}{R_g}}{R_f}-\frac1{R_g}}=\boxed{\quad \frac{R_g+R_S}{\frac{A_VR_g-R_S}{R_f}-1}\quad}
about :
Uses the LM324 transistor model (the simulation)[Eop]