The UY224 was the first indirectly heated screened grid valve produced in the USA. It was derived from the UY-227 and uses the same heater and cathode assembly.
The direct capacitance between anode and control grid is less than 0.01pF and by 1929 the Neutodyne receiver was obsolete.
The outer mesh cylinder is internally connected to the screen grid.
The close wound screen grid has a metal collar at the lower end. Within the screen grid the control grid and white cathode can be seen.
The lower end of the screen grid. In the centre the insulation around the single hairpin heater can be seen.
The top components. The top cap connects to the control grid. The cathode connects to the strut on the lower right hand side. Electrodes are held in relative place by the wires in the glass rod. Both grid windings are circular.
The balloon envelope is 45 mm in diameter, and excluding the UY base pins is 108 mm tall.
Reference: 1047. Type UY-224 was first introduced in 1929.