Re: RE: LM3914???

[Orin <orin>]

> >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 have. The data sheets have an error in their example schematics and you 
> have to analyze the info on the internals of the chip to get it right.

Really?  I did it using one of the internal voltage references
driving the voltage dividers in series with a trimpot to set max scale.
A 499 resistor in parallel with each voltage divider cancels out
differences between the chips enough for monitoring O2 sensors.
There is a picture of my board on

http://www.wolfenet.com/~orin/electronics.html

> I have a hundred circuit boards, parts, boxes and nameplates and I'll sell ya 
> one for cost plus shipping, etc., or about $45 total. You can see them on my 
> web site at www.regnirps.com on a link to the O2 readout.

I'll pass your info on to anyone that asks about my version.
Your version is nicer in that it has the brightness control
and a box.  Mind if I add a link to your page?

Orin.