"Scout" wrote in message
. ..

When you get right down to it, aren't all gauges differential?


ALL measurements of any kind are "differential" as they measure to some kind
of reference.

Differential usually refers to the active or dynamic measurement inputs, the
input being 2 and both can change. Some gauges/measurements have their own
reference built and are called "single ended". The reference is this case is
fixed whether it be pressure, voltage, length etc.