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EF73

Sensibly equivalent to:
CV466
See also:
Mullard Miniature Series Advert - Mullard EA76, EC70, EF70, EF72, EF73, EY70 DY70 Advert
    
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The EF73 from 1950 is a screened amplifier pentode for voltage amplification of low level signals. With its high mutual conductance it could be used as a wideband amplifier.
Miniature valve were constructed with end micas as larger valves but the assembly work was more precise and Mullard had a special assembly section dedicated to the hand assembly of these tiny devices.
The three grids can be seen through the envelope where the anode is of reduced section.
A close-up of the grids. They are all formed by sealing the wire to the support by notching the support and then using a peening roller to press the displaced metal over the wire.
The cathode is a rectangular box.
The intricate assembly can be seen.
The thin glass tube envelope is 10 mm in diameter, and excluding the B8D base leads is 36 mm tall.
References: Mullard data book & 1040 Type EF73 was first introduced in 1950.

 

Pin Connections
B8D & B8D/F
1
2
3
4
5
6
7
8
g1
g3
h
a
g2
h
k
a

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.2
100
100
-2
7.5
2.5
0.25M
5.5
Updated April 06, 2015.
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