The BT5B is a thyratron from English Electric. It has a mercury vapour content and is designed to operate at about 1 kV at 12 A peak. The filament is rated at 5.0 V at 4.7 A.
The short-form data books from 1971 and 1976/7 only give details for the BT5
The anode cylinder and base pinch.
Little of the internal structure is visible. The filament connection passes into the cylinder as a ribbon and appears to be coated. The other electrodes pass into the main cylinder through ceramic insulators. The base cap holds the four pins and the locating pip.
The classic envelope is 60 mm in diameter and, excluding the UX4 base pins, is 166 mm tall.
Updated October 27, 2016.