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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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10th Nov 2017, 6:44 pm | #1 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Battery valve filaments
Slightly odd question:
Is there any convention as to which pins of a B4 based triode (like PM1HF etc) are F+ and F-? I suspect it doesn't actually matter as long as the grid bias is referred to whichever is used as F-, but I'd like to know....
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10th Nov 2017, 8:17 pm | #2 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,087
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Re: Battery valve filaments
Doubt it.
Some valves, like the DAF91 it could be critical, as the diode anode is located at one end of the filament. And I suppose that for optimum design, the grid-cathode spacing (or the grid wire pitch) could be varied to compensate for the potential gradient along the filament. But in the B4-based days, I can't see that level of sophistication being incorporated. |