Old Philips code e.g.
E443
| 1st letter
- heater curent |
A |
0.06 to 0.10A |
| B |
0.10 to 0.20A |
| C |
0.20 to 0.40A |
| D |
0.40 to 0.70A |
| E |
0.70 to 1.25A |
| F |
> 1.25A |
| 1st or 1st+2nd
digit(s) - heater voltage (1=1.5V, 7=7.5V) |
| last two digits
indicate device type |
41, 51 etc. |
Tetrode with space charge
grid (G2 is control grid) |
| 42, 52 etc. |
Tetrode with screen grid
(G1 is control grid) |
| 43, 53 etc. |
Power pentode |
| 44, 54 etc. |
Triode or tetrode plus
diode |
| 45, 55 etc. |
HF tetrode with variable
gain |
| 46, 56 etc. |
HF pentode |
| 47, 57 etc. |
HF pentode with variable
gain |
| 48, 58 etc. |
Hexode frequency changer |
| 49, 59 etc. |
Hexode with variable gain |
| Suffix letter
if present |
N |
New version |
| S |
Special enhanced type |
|