The DET25 transmitting triode has a large square four pin base as can be seen from the picture. The anode box is quite large and blackened to radiate heat more effectively.

Operating frequency would be in the HF range and probably the output power was of the order of 50 Watts.

The electrode assembly can be seen in this picture. The filament is made of tape and is formed into a double inverted V. The tensioning springs can be seen to the right hand side.

Also in this picture the etched type description is typically of M-OV pattern and thus we can be sure of the manufacturer.

The wide glass tube envelope is 51 mm in diameter and, excluding the L4 base pins, is 150 mm tall.

This exhibit was last updated on 12 October 2006