# Capacitance a function of height .

1. Oct 2, 2007

### aslak19

capacitance a function of height.....

the question I find difficult is:

A liquid-level transducer consists of two parallel plates of conductor immersed in an insulating liquid, as illustrated in this figure:

http://peecee.dk/?id=71007

When the tank is empty (i.e., x=0), the capacitance of the plates is 200 pF. The relative dielectric constant of the liquid is 25.

a) Determine an expression for the capacitance C as a function of the height x of the liquid.

I have no idea what do start with???

2. Oct 2, 2007

### dlgoff

Check your text book an see if you can find how the area of the capacitor plates, distance between the plates, and the dielectric constant are related. In your problem, you start out it just air as a dielectric then as the liquid rises you have two capacitors, so to speek; one with air dielectric and one with liquid dielectric. So you'll need to know how to find the capacitance of two capacitors in parallel.

See if this will help get you started.