Type 8012 is a VHF/UHF transmitting triode and dates from the early 1940s and has a thoriated tungsten filament as did the earlier 1628.
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. The 8012A is rated at full power at 500 MHz.
This exhibit is unused.
To achieve high frequency working the leads need to be low inductance. Here the design uses pins emerging from either side of the envelope. The evacuation tube is recessed into the top of the tube. The gettering can be seen.
The evacuation tube.
The three filament wires. The centre one is the centre-tap of the filament.
The notches in the grid supports are close together showing a close wound grid.
The anode is stitched with ribbons connecting to the side pins. tape is also used for the grid connections.
A closer view.
The thin glass tube envelope is 25 mm in diameter and, including the base wires, is 113 mm tall.
References: Data-sheet & 3002. Type 8012 was first introduced in 1942.