Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001
· Uses changes in capacitance to detect part presence. Recall the basic equation.
· Works well with most materials, very good for plastics.
· If the part is conductive it acts as added surface area for the capacitive plates and increases capacitance. If the part is nonconductive it acts like a dielectric and increases the capacitance. In total the changes are normally in the order of pF.
· In the sensors the electrodes are normally round rings.
· Different materials have various dielectric properties. The list below is a sample from [Turck Proximity Sensors Guide].
