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Y-644

Sensibly equivalent to:
4CX250BC
    
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The Y-644 is described as having characteristics of the 4CX250BC but to be used in pulse mode. The 4CX250B is a ceramic beam tetrode and this exhibit has a glass envelope like the 4X150A.
The special valve holder has holes in it to allow air to pass through. The air is contained by a chimney so that the forced air cooling is directed over the large surface area of the anode ruff. Normally the chassis would be sealed air tight and a blower attached to provide a powerful air blast.
The base is a glass disc with pins protruding through. The evacuation seal is covered by a central metal spigot.
The spigot connects to the control grid g1 the base ring to the screen grid g2 and the finned top section (radiator) to the anode.
The Eimac brand name. The outer cylinder of the anode is 41 mm in diameter and 19 mm high.
A valve for professional applications the anode and folded ruff are all silver plated.
The co-axial envelope is 32 mm in diameter and, excluding the B8F base pins, is 46 mm tall.
Reference: Datasheet.

 

Pin Connections
B8F
1
2
3
4
5
6
7
8
tc
g2
k
h
k
-
k
h
k
a

 

Absolute Maximum Operating Conditions
Tetrode
Vh
Ah
Va
Vs
freq
f.max
6.0
2.4
2,000
350
165
500
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated November 16, 2016.
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