The 2D4A valve houses a pair of signal diodes with a common cathode. The valve design is from the mid 1930s and the diodes would have been used for demodulation at, probably, less than one megahertz.
This specimen is interesting because certain details of the base cap make us suspect that this valve was made at the Philips factory in Eindhoven (Holland) and imported. Probably only the 'Mullard' marking is 'British Made'. This would apparently contradict the terms of the BVA Cartel agreement which enabled Philips to exploit the British domestic market via the Mullard subsidiary.
The classic envelope is 30 mm in diameter and excluding, the B5 base pins, is 75 mm tall.
Pin Connections
|
1 |
2 |
3 |
4 |
5 |
|
a(1) |
a(2) |
h |
h |
k |
Absolute Maximum Operating Conditions
|
Vh |
Ah |
Va |
mAa |
|
4.0 |
0.65 |
200 |
0.8 |
This exhibit was last updated on 07 August 2006 |
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