| 1st letter
- construction |
G |
Gas filled |
| V |
Vacuum |
| Remaining
letters |
C |
Counter (steppinng tube
where not all electrodes are available on separate pins) |
| D |
Diodes, stabilisers etc |
| R |
Register display tubes
(nixes etc) |
| S |
Selector (stepping tube
with all outputs available on separate pins) |
| TE |
Tetrode (trigger tubes
etc) |
| PE |
Pentode |
| T or TR |
Triode (trigger tubes
etc) |
| 1st number - characteristics |
Counters, selectors |
Number of states |
| |
Register displays |
Number of display electrodes |
| |
Diodes/stabilisers |
Operating voltage |
| |
Trigger tubes |
Striking voltage on trigger
electrode |
| 2nd number if present |
Counters |
Number or output pins
if >1 |
| Final letter - base |
A-F |
Plastic base shell (octal,
B5, duodecal, tags etc) |
| |
G, H |
26-pin B26A, B27A |
| |
M, P, Q |
B7G |
| |
T |
B9A |
| |
W-Z |
Wire ended |
| Suffixes |
/R |
Tested for resistance
to vibration |
| |
/S |
Tested to military specs |
| |
/M |
Magnetic shielding (trochotrons) |
