Burroughs BD-203 & BD-316  
Written by Accutron on 2006-10-11  

Devices included in this entry:

Burroughs BD-203 unshielded MBST (pictured in thumbnail)
Burroughs BD-316 shielded MBST


The Burroughs BD-203 and BD-316 are the only known 'compact' models of beam switching tube, with a slender envelope and external magnet. The series consists of the unshielded (and extremely rare) BD-203, and the shielded BD-316. The BD-203 and BD-316 are capable of counting at 1MHz.

The short-lived BD-203 is noteworthy as being the direct predecessor to the internal-magnet BX-1000, with which it shares similar electrical and physical specifications.


Burroughs BD-203, the only unshielded external magnet MBST with a compact envelope. Note the slender envelope body which flares outward to accommodate the 26-pin base.


This BD-203 appears to be a production prototype, with no protective end caps and an improvised label originally intended for a different part number. Note the typed part number label, originally affixed with clear tape, which concealed a cut-out section of the label where the original 6700 or 6701 part number would normally be found.


Burroughs BD-316 compact-envelope beam switching tube with mu shield.


BD-316 beam switching tube. This example has a 'BD-316-1' print variation seen on some examples.


BD-316 beam switching tube, mounting bracket attached.

This article is part of the [Beam Switching Tubes] exhibit.

©2000-2019 The Vintage Technology Association. All rights reserved.