The cathode resistor should be 160 Ω and the positive anode surge is a maximum of 8,000 Volts. The anode maximum dissipation is 25 W and the screen maximum dissipation is 5.5 Watts.
Introduction was at the end of the 1940s when television receivers had picture diagonal sizes of no more than 12 inches and were monochrome only.
The fly-back phase of the line scan generates high voltages and hence the extra ceramic insulators.
There are screening boxes above the top mica and below the lower mica.
The classic envelope is 50 mm in diameter, and excluding the IO base pins is 127 mm tall.
References: 1039 Type 185BT was first introduced in 1949. See also1949 adverts.
