AustinT

I am putting together my first board and I am not sure which direction the diodes and capacitors need to go. I noticed the diodes have a black stip on one end of them so I have been matching the black strip with the strip that is on the symbol, printed on the board.

Also the capacitors I am not sure on C2,C3,C4,c7,c10,c8,c14,,c13 and c9. I cant find anything on them telling me polarity, maybe it dosent matter on these capacitors?

Thanks

Grumpy

Disclaimer, I don't have my glasses on.
But, on the ones that it does matter there is a + on one side. I can see c7 clearly enough that it isn't polarity sensitive.

AustinT

Thanks
How about diodes? Is there a certain direction to them?

Also c3 and c4 are marked on the board but not the capacitor. One wire is longer on the capacitor. Is the longer wire Positive?

Im not going to be able to finish this right away anyways. On chips u2 and u4 I orderd LM2902m-nd And I should have orderd LM2902N-nd. They are to small to fit the board.

Also one other thing How easy is this thing to use? Can it read a airfuel ratio during a hard acceleration? Or does Digital volt meter jump around, making it hard to know your actual A/F Ratio?

JPrevost

The diode is a gate. The black line goes to the ground. That way it'll let positive current go through but not the otherway. A quick test is to grab a 9v battery and test the diode with a multimeter. That's how I keep reminding myself .

------------------
, Jon (350 TBI!)
91 Red My website

AustinT

About the diode again,

The symbol on the board, for a diode, has a box with a line at one side of the box. I have been putting the black strip on the diode, on the same side as the line.

Grumpy

All depends on you sampling rate, ie how often you look at the sensor.
I use a Digital Volt Meter, and it's rate is fast enough to catch changes, yet slow enough I can read it.

If you put an Oscilloscope on it at low to medium rpm, you can see each cylinder firing.

The trick at the moment is a chep way to do datalogging with it.

I have a chip that runs open loop just fine, so I can use a voltage divider to input the WB into the oem O2s input for recording.

There are a few guys working on displays, and interfacing items.

At the DIY site there is a schematic for a LED bargraph display.

AustinT

Thanks Grumpy

Im excited to get this thing going. Now Im interested what Role do you play, or how are you involved with this whole Wide band A/F meter. You seem to be answering most all of the posts about the Meter
Thanks

Grumpy

I thought of getting organized and just doing it, getting some smart guys, some EEs etc together to work on it. Bought the sensors for the EE guys to play with. Spent weeks reading patents. Then played *cheerleader* for 3 years pushing to get it done. Nuts huh?.

AustinT

I think I speak for everyone here at thirdgen when I say, thanks Grumpy

Grumpy

Thanks, and your welcome.
R+D lab here at CSH, HQ, is still busy thou.
The WB was in part to help guys that just *don't get* plug reading. Another item is detonation. The acoustic K/S are just about little better then nothing in my mind. Gotta be a better answer <g>...