This exhibit is a mystery. The C4 reference is probably a makers code rather than the Type designation. In any event C4 cannot be found in the literature.![](../pics/abo0060a.jpg)
The pinch extends almost to the dome of the envelope.![](../pics/abo0060b.jpg)
The five base pins.![](../pics/abo0060c.jpg)
Within the envelope is a thick wire filament that is coloured a dull grey. No other electrodes are visible due to the gettering.The thin glass tube envelope is 22 mm in diameter, and excluding the base pins is 51 mm tall.References: Observation. Type C4 was first introduced in 1934. See also 1934 adverts. |
Updated July 30, 2014.
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