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PM12ASensibly equivalent¶ to:218SG 220SG S215B S22 S24See also:
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The PM12A is a most interesting valve, one of the early oxide valves from Mullard. As a contrast see the earlier PM12A with the gold paint masking the blackening caused by the azide process.
The anode consists of two small plates on a saddle of stout wire and connected to the top cap. The control grid has almost the same area as the anode plates and is threaded by a single inverted V of filament. The screen grid and suppressor grids are larger than the control grid / anode for maximum electrostatic isolation.The classic envelope is 42 mm in diameter and, excluding the B4 base pins, is 110 mm tall.References: Data-sheet & 1043. Type PM12A was first introduced in 1932. See also 1932 adverts. |
Pin Connections
| 1 | 2 | 3 | 4 | tc |  g2 | g1 | f | f | a |
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Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | Vs | Vg | mAa | ra | gm | 
| 2.0 | 0.18 | 135 | 75 | -0 | 2.0 | 330,000 | 1.5 |
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PDF scanned from an original document held by the museum |
Updated September 16, 2021.
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