The 703A is a power triode for generating RF at up to the UHF region.

The filament runs vertically and is held under tension by a spring arm. The anode is finned and semi-circular at the apex of the triangular fins. The grid is helical and held to a vertical support opposite the open end of the anode.

The balloon envelope, also known as a doorknob, is 50 mm in diameter and, including the special base pins, is 41 mm tall.

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	mAa	gm	μ	Pdiss
	1.15	4.5	400	75	2.5	12	20W

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 18 July 2007 {find valves by name}