The only things we know about this exhibit come from the printing on the metallised envelope of this imported valve. It is clearly a vari-μ tetrode for RF amplification in broadcast receivers designed for use on AC mains. The screw top cap places the date to the early 1930s.![](../pics/aai0543a.jpg)
The reverse is plain.The balloon envelope is 50 mm in diameter and, excluding the B5 base pins, is 127 mm tall.Reference: Observation. |
Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | ![](../static/key.gif)
| 4.0 | - | 200 |
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Updated March 04, 2022.
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