??? 03/07/06 01:38 Read: times |
#111460 - Filaments Responding to: ???'s previous message |
Erik said:
A NTC was standard to limit the inrush for the filaments in serially connected tubes/valves in radios. I only know tube circuits having all the filaments connected in parallel. Here some examples: http://www.tubefreak.com/hrtbrkps.gif http://www.tubefreak.com/subblups.gif http://www.tubefreak.com/subway4.gif http://www.tubefreak.com/290pwr.gif http://esc73.midphase.com/~schehol8..._schem.pdf http://esc73.midphase.com/~schehol8..._schem.pdf http://esc73.midphase.com/~schehol8..._schem.pdf Here, current limiting is provided by finite impedance of secondary winding of mains transformer. Kai |