The BTH B11 dates from 1927 and was designed for audio output. It has an amplification factor of 3.5.This valve was not clearly marked with a type designation. As the single strand inverted V thoriated filament was intact the valve filament was heated to check its rating. The filament was slowly energised by a constant current source to minimise thermal shock. At each current setting the voltage across the filament was noted. Armed with a list of filament requirements for the BTH valves of the period, the current was increased until a match was obtained. This exhibit took 0.6A at 6.0 volts and the filament glowed an orange/yellow.
The construction of the electrodes is made rigid with stout support rods.The balloon envelope is 43 mm in diameter, and excluding the B4 base pins is 97 mm tall.References: 1043 & Data. Type B11 was first introduced in 1927. See also 1927 adverts. |
Pin Connections
| 1 | 2 | 3 | 4 |  a | g1 | f | f |
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Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | Vg | mAa | ra | gm |
| 6.0 | 0.5 | - | - | - | 2,500 | 1.4 |
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Updated January 19, 2023.
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