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NT40

Sensibly equivalent to:
CV1223 CV384 DET5
See also:
CV384 short entry - CV1223 short entry
    
Extras ▼

 

The NT40 is a pre CV designation of a UK Navy Transmitting valve. The NT40 is the GEC DET5 valve.
This low power transmitting valve was directly derived from the PX25 audio triode.
For transmitter use the same complex anode box was used but fabricated from Molybdenum. The NT40 has a directly heated oxide filament and is pumped to a hard vacuum to enable operation up to 600 Volts on the anode. The anode dissipation is 25 Watts and the operating frequency was of the order of 20 MHz. The design was popular and used in several designs.
The balloon envelope is 62 mm in diameter and, excluding the B4 base pins, is 143 mm tall.
Reference: Datasheet & 1005.

 

Pin Connections
B4
1
2
3
4
a
g1
f
f

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
μ
4.0
2.0
600
-
62.0
1,270
7.5
9.5
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated April 09, 2015.
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