The A110 from Philips was designed for HF and LF use in radio receivers. The very low heating requirement points to a dull emitter type, probably thoriated tungsten.
Etched into the envelope are the words imported from Holland.
The etched lettering and within the horizontal anode.
The balloon envelope is 42 mm in diameter, and excluding the B4 base pins is 74 mm tall.
Reference: 3002. Type A110 was first introduced in 1925.
Absolute Maximum Operating Conditions¶
Updated October 28, 2014. shape:balloon construction:pinch type:triode age:1920.1930 base:b4 pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f