circuit number 3

we had to build a ocean sesnior, we got given a plan sheet had to figer out the the all diffrence resistors we new the value of R6 at 10k

I stared from D2 the !st diode after V.S we needed to kno what was the V.D whichh is 0.6 we end up with 11.4v after the diode to R5 we didnt have the value use smple ohms law to figer out the value.We new the Z diode was at 9.1v there is a capacitor ther aswell to keep the voltage stayble. I worked out that R6 V.D is gota be 8.4V because we need 0.63v (I= V/R = 0.00085a). we kno from kurchofs law that in a series circuit the current shold always be the same at any point.
Then again we used ohms law to figer out R8 R= V/I = 740ohms
same for R7 we had the voltage after R8 which was 0.23v (R=V/I).

R5 13411 ohms
R6 10k ohms
R7 270ohms
R8 740ohms

then we go to the paraelle side of the circuit and had to work out R2,R3,R4.
we new 11.4 is come to the output of the op amp going to the L.E.D haveing the voltdrop of 1.8v, useing ohms vs-vd=9.6 and we kno the current is 9.5mA V/I=R 9.6V/9.5mA = 1010ohms. we did same thing for R4.
for R3 we had a diode and a l.e.d 0.6vd for the diode and 1.8vd for l.e.d which gives us 9v R=V/I 9V/9.5MA=947OHMS.
I KNO HOW THIS CIRCUIT WORKS IN THERORY BUT DIDNT BUILD IT

WORKING OUT:
R8 v/i=r 0.63/0.00085 = 740ohms
R7 " " 0.23/0.00085 = 270ohms
R2 " " vs-vd = 9.6,9.6/9.5mA = 1010ohms
R4 " " " " " " " " " "
R3 vd+vd = 2.1 vs-tvd 9 v/i=r 9v/9.5mA=947ohms