Physics/EE people... help?

[gopunk]

can somebody just explain to me why you can touch a capacitive touch sensor through glass and it will work?

my understanding is this... capacitive touch sensors work by sensing when there is more capacity for elections. so when you touch it, it goes "whoa electrons can go into your body" and thus you are sensed. but i thought glass, paper, plastic were dielectrics meaning electrons can't freely flow through them? so how does the sensor detect your touch through these materials?

thanks

 

[gopunk]

bump

 

[RaynorWolfcastle]

electrons are irrelevant (well in the sense you're thinking of), capacitance is inversely proportional to the distance between the plates of the capacitor. I'm guessing most of these sensors work by having some sort of compressible dielectric between the plates. When you press down on the sensor, the capacitance of the device changes; this is what the device measures (through voltage, likely)

 

[dighn]

n/m