harry wrote:
On Jan 6, 5:25 pm, The Natural Philosopher
wrote:
Neil wrote:
If you have a container and you put two vertical parallel wires in it,
why can't you determine the quantiy of a liquid poured into that
container based on the resistance measured between the two wires?
you can.

If the material is conductive.

You can also measure the capacitance if its an insulator

But modern oil gauges and height gauges prefer to use ultrasonic
rangefinding on the top of the liquid.

Not always a good idea to have electrical conductors in flammable liquids..

The traditional automotive petrol guage sender is immersed in petrol/
petrol vapour. No danger if there is no air.


Much traditional instrumentation in boilerhouses depends on electrodes
immersed in water or sometimes mercury eg for determining draught in
chimneys and CO2 levels in combustion gases via the resistance of the
water.

Fluids don't have capacitance.

two wires dipped in them, do, however.


They might have permittivity.
http://en.wikipedia.org/wiki/Relativ...c_permittivity