indirectly heated cathode การใช้

Indirectly heated cathodes enable the cathode circuit to be separated from the heater circuit.
In the 1930s indirectly heated cathode tubes became widespread in equipment using AC power.
Excess heater-to-cathode voltage in indirectly heated cathodes can break down the insulation between elements and destroy the heater.
Directly heated cathode tubes continued to be widely used in battery-powered equipment as their filaments required considerably less power than the heaters required with indirectly heated cathodes.
A superior solution, and one which allowed each cathode to " float " at a different voltage, was that of the indirectly heated cathode : a cylinder of oxide-coated nickel acted as electron-emitting cathode, and was electrically isolated from the filament inside it.