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MH4K

Sensibly equivalent to:
41MTL AC/HL AR17 CV399 CV1037 D4 HL4 MH4 NR31 VR37
See also:
Catkin Valves - The Metal Valve - Some Important British Valves - Osram Catkin Advert
    
Extras ▼

 

This Marconi/Osram MH4 (MH4K) valve was a manufactured as a Catkin. The Catkin construction was derived from the large Cooled Anode Transmitting valves, and these also featured a shaped copper anode sealed to a glass envelope.
The date of the catkin design was 1933 and was clearly made for use in all-mains radio receivers.
The design was also with a conventional glass balloon envelope also with the designation MH4.
The thin metal tube envelope 25 mm in diameter and, excluding the B5 base pins, is 95 mm tall.
References: Datasheet, 1005, 1043, 3002 & 1040. Type MH4K was first introduced in 1933.

 

Pin Connections
B5
1
2
3
4
5
a
g1
h
h
k

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
4.0
1.0
250
-4
5.0
11,100
3.6
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated February 07, 2013.
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