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.
• Plate detector circuits were commonly used from the introduction of indirectly heated cathode tubes in the late 1920s until the start of World War II . As R . F . tubes became more sensitive, grid-leak detectors ( which are more sensitive than plate detectors ) became less practical.
• It had an indirectly heated cathode running up the middle, surrounded by two separate sets of wires one radial, one axial forming a cylindrical grid array, and finally a dielectric storage material coating on the inside of four segments of an enclosing metal cylinder, called the " signal plates ".