(under the class definition) Devices provided with means to prevent the emission of secondary electrons from some part of the device.
(1) Note. Discharge devices which have one or more control electrodes and in which the only means provided to suppress the secondary emissive is that one or more of the control electrodes may be used as a secondary emissive suppressing electrode are not included in this or the indented subclass but will be found in subclasses 293+, or one of the subclasses specified in the notes thereto.
