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LS3

 
See also:
The Dawn of Broadcasting in the UK
    
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The LS1, LS2 and LS3 were the first receiver type power valves produced by M-OV. They were specifically designed for audio use as the final stage in a receiver.
It can be seen that these early bright emitter audio power valves were the first steps on a road that developed the LS5 and LS6A (LS6A) and ultimately the PX4 and PX25.
The Type identification is feintly etched into the glass.
The construction follows the pattern of the R Type with horizontal cylindrical anode with helical grid and single strand tungsten filament.
The grid is held to the grid support by a thin wire wrapped around the rod and grid loops. The filament is broken and like all tungsten wires is held in a fold of the support.
The grid loops.
The envelope carries the type one BBC stamp. 'Type Approved by Postmaster General'
The balloon envelope is 54 mm in diameter, and excluding the B4 base pins is 94 mm tall.
References: 1003 & 1005. Type LS3 was first introduced in 1923.

 

Pin Connections
B4
1
2
3
4
a
g1
f
f

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
4.0
0.65
200
-
-
10,000
0.45
Updated July 11, 2014.
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