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NR15A

Sensibly equivalent to:
410LF CV1152 L410 PM4DX
See also:
The Azide Process - M-OV NR15A Box - CV1152 short entry
    
Extras ▼

 

The NR15A is a British Navy triode receiving valve. Introduced in 1924 it was the first naval valve to have an oxide coated filament. This valve looks to have been made by the Azide process.
The photograph is essentially an M-OV type L410 manufactured during the mid to late 1930s. Although the Azide process was essentially obsolete by this time it was used occasionally, and British Navy specifications may have remained unchanged for years after the technology altered.
This example dates from 1936 by which time it was known as the 'Lord Louis' valve in honour of the improvements Lord Louis Mountbatten is reported to have suggested.
The balloon envelope is 40 mm in diameter and, excluding the B4 base pins, is 85 mm tall.
References: Datasheet, 1043 & private communication. Type NR15A was first introduced in 1924.

 

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
0.1
150
-4.5
3.9
8,500
1.76
Updated April 04, 2015.
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