The filament transformer will limit the current to a large extent. Also, the
resistance of the filament or heater will rise very quickly when the voltage
is applied. For example, the TH347 filament reaches rated current in just a
few milliseconds. I haven't measured the current of an indirectly heated
cathode tube but you can see the color of the heater turn red almost
immediately
when voltage is applied, suggesting that the resistance has increased
substantially.
73/k5gw
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|