Sensibly equivalent¶ to:
The WWII VR91 in a plain aluminium screening can. The VR indicates that it was supplied to the RAF and that the date of manufacture was before the introduction of the CV register in 1941.
This amplifier pentode was a general workhorse. It was extensively used in radio and radar during WWII.
The pins are equi-spaced around the circumference of the pin circle. Correct location in the valve-holder was ensured by the key on the base spigot.
The can is plan aluminium except for the utility identification on one side.
The wide glass tube envelope is 33 mm in diameter and, excluding the B9G base pins, is 60 mm tall.
References: 1040. Type VR91 was first introduced in 1938.
Absolute Maximum Operating Conditions¶
Updated March 15, 2021.