What is an electronic grid?

   Electronic grid, in radio, is a conductor (electrode) used in a triode (vacuum tube) to control flow of electrons, or plate current, between the cathode and the anode. It generally consists of spiral or mesh wire which surrounds the cathode and in turn is surrounded by the anode. Effectiveness of the grid in controlling plate current is determined by the tube construction. Small cathode-grid spacing increases control action of the grid.