7 Nov
2007
7 Nov
'07
5:04 p.m.
On 8 Nov 2007 at 0:17, Tony Duell wrote:
This may be a UK .vs. US language difference, but to
me :
A 'filament' is a thin wire, heated electircally. A heater (in a valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated cathode'
A filament that heats a separate cathode is called a 'heater'. The result
is caleld an 'indirectly heated cathode'
Some of it is context-related in the US, at least. Transformers are
said to be "filament transformers" if their intended use is to power
the heater. The glow from the heater (indirectly or directly heated
cathodes) is usually said to be a "glowing filament". Many older
handbooks show basing diagrams with "F F" particularly if it's a
directly-heated cathode. The glowing element in a Tungar bulb is
usually termed to be the filament.
Finally, some call a heater a "filament" and a "cathode" the heated
emitting sleeve.
It's one of those things wherein what's intended is rarely a mystery.
"Plate" for "anode" is common usage here in all but special-purpose
devices, such as CRTs.
Cheers,
Chuck