Assertion: tube's filament | /r/HasProperty | heated
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: The battery version commonly used tubes where the filament was heated by a single 1.5-volt dry cell and plate voltage was supplied by a (nominally) 90-volt battery.
text: A considerable amount of heat is produced when tubes operate, from both the filament (heater) and the stream of electrons bombarding the plate.
text: The filament of an indirectly heated cathode is usually called the heater.