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41MHL

Sensibly equivalent to:
354V A30D AC/HL CV2504 D4 HLA2 MH4
See also:
Cossor 41MHL Box
    
Extras ▼

 

This 41MHL has lost its identification but the reduced size of the gettering compared to 41MHL allows a clear view of the construction.
The 41MHL is an indirectly heated triode and was suitable for detector or audio amplifier in a radio receiver. Internally the valve has both a control grid and a screen grid. The latter is internally connected to the anode by a length of coiled wire.
The 41MHL was also supplied as metallised.
The anode box measures 18 x 11 mm.
The pinch and lower mica components. The oxide coated cathode stands out white.
The top mica. The screen grid passes flat across the face of the anode. The control grid has been shaped to follow the curve of the cathode tube.
Here the coil connecting the screen grid to the anode is very clear. What is not clear is why a triode was made in this way.
The balloon envelope is 54 mm in diameter, and excluding the B5 base pins is 111 mm tall.
References: Datasheet, 1043, 3002 & 1040. Type 41MHL was first introduced in 1930.

 

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
200
-3
4.0
11,500
4.5
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated March 21, 2014.
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