Type VT228 is the RAF service code for the commercial UHF triode Type 8012 and this exhibit carries both names.
Type VT228 is a VHF/UHF transmitting triode and dates from the early 1940s and has a thoriated tungsten filament as did the earlier 1628. It is designed for forced air cooling.
The control grid can pass up to 14 mA grid current and dissipate 1.6 W. The maximum frequency of operation is in the region of 500 MHz.
Also etched into the glass is the old UK stores code of 110E/171
Slater - the maker's name and their logo.
This valve is unused. The three stranded, twisted and tinned base wires are filament connections including a centre tap connection.
The re-entrant moulding of the glass leading to the base pinch.
The re-entrant top moulding of the envelope showing the evacuation tube on the extreme left.
The thin glass tube envelope is 25 mm in diameter and, excluding the base wires, is 95 mm tall.
References: Data-sheet & 3002. Type VT-228 was first introduced in 1945. See also1945 adverts.
