Assertion: tube's number | /r/HasProperty | roundedheater voltage
Facets:
Source sentences:
text: The first number is the (rounded) heater voltage; the letters designate a particular tube but say nothing about its structure; and the final number is the total number of electrodes (without distinguishing between, say, a tube with many electrodes, or two sets of electrodes in a single envelope—a double triode, for example).