Re: LM3914???

[clive@problem.org (Clive Apps - 510-0020 )]

> 
> At 12:36 PM 2/7/00 -0500, you wrote:
> >The only drawback to this module is that it has an on-chip 10/1 divider, so
> >it reads 1.2V to 12V in... rather than 0-1V.  Good idea though.
> 
> I had wanted to gang 2 or more of the 3914's together, feed the O2 thru a
> op-amp and then have a higher resolution scale.   I was never able to
> figure out exactly how to do this... I'm more programmer than H/W guru.
> 
> Anyone ever do this?
>  
> >I made this and it works well, except I made eight on one board, using eight
> >10-segment bar graph LEDs, allowing me/us to monitor Air/Fuel on each
> >cylinder of an engine on a dyno.
> 
> I WW'd my own, sure looks nice hanging from the rear-view mirror.  


make the op amp a x20 amp
drive the 2 displays in series as per the 3914 datasheet
you need ~20v to cover the 2 displays

so you have to have an aux power unit
to get the required 20v to drive the displays for 20 segments


use the offset on the opamp to centre the displays
it really is a lot of work to get the extra segments

Clive 
----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo@lists.diy-efi.org