tubes work by not just thermionic emission (that'd be a diode) but also by a sort of uncanny leveraging of inverse square laws in free space surrounding the gri

tubes work by not just thermionic emission (that'd be a diode) but also by a sort of uncanny leveraging of inverse square laws in free space surrounding the grid. when the first tube amplifier was invented, it was by accident, it wasn't understood how it worked.