Yesterday, my GE refridgerator stopped cooling.  The compressor would not turn on.  I discovered that the "start relay" was the problem.  ( See pic#1.) 

I took the bad "start relay" apart and found it contained a "ceramic"? disk on the inside, about the size of a US nickel, in thickness and size. Mine was broken into several pieces so would not work. ( See pic #2 ). 

Once I replaced this "start relay", all is working now and has been for 24+ hrs.    Here is a pict of a NEW "start relay", that I opened up to see the ceramic disk....  ( pict#3 )


HERE is the question....   What exactly is this ceramic disk?  How does this function?  It is like no "relay" I have ever seen.  What is the electrical theory behind this?  Thank you.