The MHLD6 was developed for military and professional applications which demanded valves rated to operate from 6V supplies, notably vehicle batteries.

This was at a time, later 1930s, when domestic British AC mains radios still used valves with 4V heaters.

The MHLD6 is also known by the pre-WW2 RAF service designation of VR101.

The double diode triode was used in superhet radio receivers. The diodes would rectify both signal and AGC lines, and the triode would act as the first audio amplifier stage.

The classic envelope is 36 mm in diameter and, excluding the IO base pins, is 93 mm tall.

This exhibit was last updated on 30 December 2001