Sensibly equivalent¶ to:
The 1R5 is a frequency changer heptode for a battery portable broadcast radio receiver. The heptode or pentagrid structure has two control grids g1 & g3 with screen grids held at RF ground at g2 & g4. G5 is the suppressor grid.
The valve would be made to self oscillate, and the intermediate frequency would be extracted from the tuned anode circuit. The oscillator would probably be generating 15 Volts peak to peak.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 46 mm tall.
References: Datasheet, 1040 & 1043. Type 1R5 was first introduced in 1945.
Absolute Maximum Operating Conditions¶
Updated January 27, 2013. shape:thin.glass.tube construction:all.glass type:heptode age:1940.1950 base:b7g heater:1.4v pins:7 pin:1.f- pin:2.a pin:3.g2.g4 pin:4.g1 pin:5.f- pin:6.g3 pin:7.f+