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 .

CIRCUIT TWO ( USING LINEAR REGULATOR)

circuit Liner Regulator

This adjustable liner regulator is used to support the input voltage and the otput voltage.
In this circuit the supply voltage is 12V and various componints are used to for the purpose of voltage drop and LED to physically see if the circuit is working (warning light) and capacitors are used to store energy and release back when switch off.
The purpose of this circuit is to find out the value of voltage out as we did in our calculation which was 5 Volts , this gain value depends on the value of risistors R3 and R2 from the formula.

Calculatioin:
Calculate of the values R3, R2
Vref= 1.25         Vout must = 5V
Use Vout= Vref (1+R3/R2)
Vout = vref (1+R3/R2)
5V= 1.25 (1+R3/R2)
5V/1.25= 1 + R3/R2
4 - = R3/R2
3<R2 = R3
R1 = Vs - VLed/I= 5v - 1.80VLed/ 0.02= 160 ohms
R1= 160 ohms
R2= 240 ohms ( from data sheet)
R3 = 3>R2 ( 3*240= 720 ohms)
R3= 720 ohms.

Designed of circuit on Loc Master 03

I have started to builed the circuit used these components:
One LM317 regulator, three risistors R1180 ohms, R2= 280 ohms R3= 860 0hms. one 1.8V LED, two 25V 47uf capacitors, two 1N401 diodes and one zener diode

Test

First checked the voltage out of cicuit 1, 5.2V out , 2 0V , 3 12Vout.

Checked availble voltage in varios points, the result was positive, available voltage after D13 , 11. 35V which is voltage drope 0.65V, 11V for both zener and C15, avilable voltage before R3 on adj 3. 82V, after R3 availble voltge 0V , across R1 volage drope 3. 01V , and across LED 2V and out is exactky 5.2V that which we got on our calculation.

Problems;
in this crcuit which i buled i had no problem, because my calculation was correct and choesed the correct componint for this circuit and also works perfect which i expected.
Reflection:
Itry to make the circuit simple as possible and used the componint mathematically approved .
next time i hoppe i will make batter circuit than this one .