Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
In Reply to: Re: Positive temperature coefficient of Tungsten. posted by Ehien on November 21, 2002 at 15:58:30:
Sorry to intervene ... heater currents are in Ampere range, not 0.6mA. You lost three zeroes somewhere.Surge current: it's simpler! Current through a cold indirect filament is about 3-4 times higher than a fully warmed up.
Around the nominal Uf voltage, If changes +1% for every +3% of Uf voltage. It's not linear regulation, but approximation is OK in a narrow 'legal' Uf range.
Some actual warmup data - see the link. In the good old days, in addition to brief datasheets, factories issued detailed docs with similar warmup charts, glass surface temperature charts, etc...
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: Positive temperature coefficient of Tungsten. - klaus 17:06:08 11/21/02 (5)