Sensibly equivalent¶ to:
The UU7 is a full wave rectifier.
Essentially the UU7 is a UU5 on an MO base. Quite why they decided to metallise these rectifiers remains a mystery but the only obvious consequence was that they tended to overheat until the metallising corrected the problem by flaking off! This series of rectifiers was not as robust as the stalwart UU5, at least until the 1950s when Mazda seem to have realised that domestic HT rectifiers do not need metallisation as with this valve.
The maximum reservoir capacitor is 16 µF.
The classic envelope is 43 mm in diameter, and excluding the MO base pins, is 97 mm tall.
References: Data-sheet, 1040 & 1043. Type UU7 was first introduced in 1938. See also 1938 adverts.
Absolute Maximum Operating Conditions¶
Updated January 03, 2022.