Page 47 - Curriculum Visions Dynamic Book

(Right) Ceramic capacitors (the brown disks without the coloured bands).
See Vol. 1: Plastics for more on plastic.
can be fired with its electrodes in place. Leads are then soldered to the electrodes. The whole ceramic and electrode combination is then sealed inside a plastic.
Recently it has been possible to develop new ceramics that fire at lower temperatures. As a result, copper or nickel electrodes can be used in place of the expensive palladium ones.
Ceramic capacitors also form the heart of computer memory chips – RAMs and DRAMs.
Piezoelectrics
piezoelectrics are materials that produce an electric voltage when they are pushed, pulled, or twisted. The same ceramic used in a capacitor will also produce
a voltage when a force is applied to it. This happens because stress on the material makes electrons in it
(Left) Piezoelectric igniters are common in gas cookers. 47