Bill,

For printed materials, the only time I have seen confusion is with 
"mixed" supplies on one schematic sheet.  I know of no convention for 
this.  

But, if you're referring to schematic capture tools and libraries of 
components, that can be a whole diffeent story...

Doug

Bill Moore wrote:
> 
> I have a question regarding schematic drawing conventions:
> 
> I see two conventions used in drawing simple power supply
> schematics. The first is that circuitry always flows toward
> ground synbols that are at the bottom of the schematic. This
> supports the 'ground is always at the bottom' philosophy.
> Positive supplies are universally shown this way - no argument
> here, and many negative supplies are also shown this way.
> 
> But, I've also seen negative supplies drawn with the negative
> voltages toward the bottom, with the flow of the rest of the
> circuitry going upward toward ground, which is actually
> drawn at the top of the drawing (ground symbol is -always-
> drawn correctly though, with the point down). This method
> supports the 'most positive at the top, most negative at the
> bottom, ground somewhere in the middle' philosophy, much like
> how voltages would look on a graph, or on an oscilloscope.
> 
> Is there a preferred or proper convention? Does it really
> matter? Are there standards that would answer this question?
> 
> Curious minds want to know!