This exhibit was last updated on 13 January 2013
The OTH231 is not the valve type it is probably a reference number. The type is in Russian. On the envelope someone has written that the valve is probably a high current rectifier. On close inspection it is much stranger than that. The two large cavities are linked by a rod across the top. At the centre of one cavity is an indirectly heated cylindrical cathode. Its cavity has a rectangular opening into the centre of the valve. There the electron stream passes through a hollow electrode and thence into the other cavity. At the middle of the second cavity is a three mm rod that extends down to the pressed glass foot and to a base pin. The cavities could be screens and the valve may be a thyratron with the hollow electrode as the control.
The wide glass tube envelope is 55 mm in diameter and, excluding the special 10 pin base pins and spigot is 100 mm tall.