Assertion: resistor's number | /r/CapableOf | use a filament lamp
Facets:
value: as the ballast
type: MANNER
value: in the late 1950s
type: TEMPORAL
value: through to the 1960s
type: TEMPORAL
Source sentences:
text: A number of fluorescent lamp fittings used a filament lamp as the ballast in the late 1950s through to the 1960s.