Power ground

[Jim Davies]

On Sat, 2 Jan 1999, Clarence L.Snyder wrote:

> > Anyone have time to explain the difference between 'ground' and
> > 'powerground'?
> > TIA
> > Geoff
> I'll give it a crack.
> In a DC power system on a car, the negative(usually) terminal uses a
> "chassis ground" for power "return".This is your "power ground". It can
> have a voltage drop of up to .1 volt across it for accessory and
> charging loads, and up to one volt for starter loads.
> For signal circuits, such as sensors, sometimes the .1 volt drop across
> the frame ground could cause calibration errors, so a "signal ground" is
> provided. Sometimes the signal can even "float" above chassis ground, as
> through a protection diode with a, say, .6 volt forward voltage drop.
> Can't use chassis ground return for such a signal.
> Hope this helps understand it.
> 

So in other words, high amperage and low amperage devices should have
seperate ground paths to the battery??