cathode, filament, and grid from Raytheon 24A vacuum tube
Date: 1922-1930
Inventory Number: VT5198
Classification: Vacuum Tube
Subject:
Maker: Raytheon Manufacturing Company (founded 1925)
Cultural Region:
Place of Origin:
Dimensions:
0.3 x 2.9 x 0.4 cm (1/8 x 1 1/8 x 3/16 in.)
case: 4 x 3.6 x 3.6 cm (1 9/16 x 1 7/16 x 1 7/16 in.)
Accessories: red cardboard cylinder case
Description:
Three elements of an amplifier vacuum tube: the cathode which is a thin metal tube; the grid, which consists of a pair of parallel metal rods with a thin wire wound around them in spiral; and the cathode heating filament, which is a ceramic rod with two electrical connectors.
Signedunsigned
FunctionThese are some of the elements of an amplifier vacuum tube. The cathode is meant to be connected to a large negative voltage with respect to another (absent) element which would be the anode. It produces electrons that migrate towards the anode. The grid would originally be put around the cathode and would be at a voltage slightly more negative than the cathode and connected to the signal to be amplified. Electrons traveling from the cathode to the anode would be blocked by the grid in proportion to the voltage difference between the grid and the cathode, which in effect makes the current travelling between the electrodes to reproduce the input signal with more intensity. The filament is simply the heater that is inside the cathode to cause the electrons to jump from its surface.