(under subclass 206.1) Subject matter in which the photocell has plural electrodes, one or more of which is photoemissive, and in which secondary emission takes place.
(1) Note. Secondary emission is the emission of electrons from a material when bombarded by primary electrons. The secondary emission may take place at the photoelectric cathode or at one or plural other electrodes.
SEE OR SEARCH CLASS
330, Amplifiers,
42, for amplifiers having a secondary emissive tube.
