Capacitor with Irregular size dielectric

[TenJuu]

Main Question or Discussion Point

Is it possible to make a capacitor with a dielectric not of the same size with its conducting plates?

 

[berkeman]

Welcome to the PF.

Is it possible to make a capacitor with a dielectric not of the same size with its conducting plates?

Sure. But can you think of any practical reason why you would WANT to do that? What kind of dielectric change like you suggest would make the capacitor better in some way?

 

[Lord Crc]

Well it certainly would be cheaper to construct if you don't require tight tolerances...

 

[TenJuu]

Welcome to the PF.

Sure. But can you think of any practical reason why you would WANT to do that? What kind of dielectric change like you suggest would make the capacitor better in some way?

We are having research on making a security alarm with low technology. By making the car window as our dielectric and having small conducting plates sandwiching it. When the glass is broke it will cause a change in capacitance thus triggering our circuit.

 

[Lord Crc]

Capacitive sensing is a common technique, see for example https://en.wikipedia.org/wiki/Capacitive_sensing