The PM22 output pentode was designed for battery operation.The filament and anode voltages are printed onto the top of the envelope together with the type designation.The anode load impedance required is 8,000 Ohms.Additional details can be found on this second data-sheet.Both four and five pin versions were made, the connections given are for the five pin version.The balloon envelope is 47 mm in diameter and, excluding the B4 base pins, is 88 mm tall.References: 1931 data-sheet & 1043. Type PM22 was first introduced in 1928. See also 1928 adverts. |