Circuit 3

My third and final circuit to be made was to work in conjunction with a vehicles oxygen sensor, and should give readings via LED's to interpret the state of the vehicles air/fuel ratio.

To achieve the necessary outputs to engage each LED i would need a semi-complicated circuit involving a triple Op Amp chip.

Other than the chip itself, me circuit consisted of:

3 x 1K Resistors

1 x 10K Resistor

1 x 410ohm Resistor

1 x 470ohm Resistor

1 x 270ohm Resistor

1 x 9.1v Zener Diode

3 x 1N4001 Diodes

2 x 0.1 uF Capacitors

3 x 5mm LED's (Red, Yellow, Green)

This circuit was much more difficult to map out than the previous circuits, as not only was it alot more complex, but we also had a restricted amount of space to fit it into, and also the pin-outs on the chip were not always in the easiest place to tap into. 

This meant that alot of trial and error on the computer screen was necessary. 

Once I had completed this seemingly possible task, i set to acquiring my components and creating my circuit.

This required alot more skill than the last two, as the whole circuit was alot more compacted in design. After a couple of hiccups in the build process, the circuit seemed to come together nicely. 

When i went to test it however, i found that the potentiometer setup that we have been supplied for the testing of our circuits, was faulty, and a short circuit somewhere inside the potentiometer had caused it to have a steady output of 5v, which is the input voltage it had been given in the first place. This is also far too high for our circuits to be tested on, as they are designed for fluctuations between .1v and 1v. 

This meant i had no correct way to test my circuit. From what i did see though, i found i had a loose connection in one of my Op Amp pin-outs, which caused one of my LED's to flicker when touched.