Capacitor with Irregular size dielectric

AI Thread Summary
It is feasible to create a capacitor with a dielectric that does not match the size of its conducting plates. The discussion raises questions about the practical benefits of such a design. One proposed application involves using a car window as the dielectric in a security alarm system, where breaking the glass alters capacitance and triggers the circuit. This approach highlights the potential for cost-effective construction without strict size tolerances. Capacitive sensing is identified as a relevant technique for this application.
TenJuu
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Is it possible to make a capacitor with a dielectric not of the same size with its conducting plates?
 
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Welcome to the PF. :smile:
TenJuu said:
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?
 
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Well it certainly would be cheaper to construct if you don't require tight tolerances...
 
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berkeman said:
Welcome to the PF. :smile:

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.
 
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
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