filament voltage การใช้

Emission may usually be restored by raising filament voltage.
Tube-based transmitters must have power applied in the proper sequence, with the filament voltage applied before the anode voltage, otherwise the tubes can be damaged.
Early TRF sets had typically two or three tuning knobs and tube filament voltage-control rheostats, all of which had to be set correctly to receive a station.
Upon energisation of the filament only with the rated filament voltage ( 1.5 V ), in a darkened room you can just see it glowing a dull red.
Later ( late 1920s ) TRF sets had ganged tuning ( one knob was used to control all stage tuning capacitors simultaneously ), AC house current operation, and eliminated the filament voltage adjustments.