O2 sensor Tester Circuit

O2 Sensor Circuit

Calculation:
Formulla volatage drop= (R above / R total) * Vin
Vd= 9.1 - 0.63v= 8.47, Vin = 9.1V, R above= 1000 ohms
8.47= (1000/ Rt) * 9.1, 0.9307= 10000/Rt, Rt= 10747.8 ohms= 10744 ohms
Rt= 10774= R6+R7+R8
Rt1= R8+R7=10744- 10000= 744 0hms
Vd=0.63 - 0.23= 0.4V , Vin = 0.63v , R above=R8
0.4v=(R8/Rt1)* 0.63= 0.6349,  R8 = 0.6349 *RtI
RtI * 0.6349= R8
R7= RtI - 0.6349RtI = 0.36 50*744=271.61 =272 ohms
R7= 272 ohms
R8= 744- R7 (744- 272)=472 ohms
R8= 472 ohms
LED, Red= (12v - 0.7v - 1.8v/ 0.0095 Amp=1000 ohms
LED, Yellow= 12v - 0.7v - 1.8v / 0.0095 Amp =1000 0hms
LED, Green = 12v - 0.7v - 1.8v /0.0095 Ams= 1000 ohms
R5= Vs/ Is
Vs= 12v- 0.7v - 9.1v = 2.2V
Is= Izener+ I total R6
It R6=9.1v/ 10000 ohms=0.00091 Amp
Iz=0.0056Amp
Is= 0.0056 + 0.00091= 0.00651 Amp
R5= 2.2V/0.00651= 337.9 ohms
 

Componint:
R2= 1000 ohms
R3 = 1000 ohms
R4 = 1000 ohms
R5 = 330 ohms
R6 = 10000 ohms
R7 = 270 ohms
R8 = 470 ohms
Capacitors 1, 2 = 50v , 0.1 uf
Zener diode= 9.1V
Rectfier diodes 2, 3, 4 = IN 4001
LED's = Red, Yellow, Green

Testing:
Vd Diode 1= 0.7v that is knee voltage which diode works
Capacitpor 1 = 12.20V available voltage the capacitor is fully charged.
R4= 2.85V
Capacitor 2 = 9. 31V fully charged
Zener diode = 9. 30 V which the zener diode conected revers biased region
R6= 8. 4V
LED red= 2.2V thats tells us the light as inverting voltage of op-am greater than non inverting.
R3= 8.85v
R8= 0.40v
R7= 0.28v
Diode 4= 0.06v
Led green= 1.59v.

EXPLINATION:
This is an oxygen sensor tester circuit, which is potential devdercircuit. Divide onto three region on depending an oxgyen sensor signal. It is light up LED's for each region which was set up with diffrent resistors.
Three regions are lean region is green LED from 0.1 - 0.23v normal is Yellow LED from 0.23v - 0.63 V the riches LED is red 0.63V - nearlly 1V .
If we connect this circuit to vehicle oxygen sensor on idle the LED's are will be blanke at acclretion the red LED should be on in diaccliration the green LED will be on .

PROBLEM:
When i build this circuit for first time i powerd in and conected to O2 sensor the red and yellow LED's on same time the green LED on in the low voltage it ok. Then i cheked i found the problem it was shortage. After that the yellow LED is on but not bright and also after R6 and R7 i got high voltage i notced after volatge drop and cheked the resistors it was my mistake i had wrong resistors when changed the resitor  i got pefect reading and the ciircuit works fine.

Reflaction :
In this crcuit ihad some problem fourtunaly i found the mistake and slove the problem , it was litile bit hedache for me ,but this good experince for me i learend alot aand i hope i will build better then this one i can .