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ME1400

Sensibly equivalent to:
CV432
See also:
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The ME1400 is an electrometer pentode for use in high resistance circuits for such applications as PH meters, photocell units and valve voltmeters.
The input current into g1 is of the order of 10 to the -11 Amps. The maximum anode voltage is 90 Volts and the maximum cathode current is 1.0 mA.
Gerry Horrox of Crowthorne Tubes has provided information that the special quality ME1400 was developed from the EF37A and in addition to its specific design use as an electrometer pentode it functions well in studio audio equipment where it would be running at 6.3 Volt on the heater and up to 250 Volt on the anode . Edition 20 of the AVO manual gives the heater as 6.3 Volt. The second set of operating conditions reflects this audio use the first set are from the original Mullard data.
AS the red metallic paint has fallen off and the internal structure can be clearly seen. The cathode and inner grids are at a considerable distance from both g3 and the anode.
A closer view.
The wide glass tube envelope is 30 mm in diameter and, excluding the IO base pins, is 86 mm tall.
References: Datasheet & Gerry Horrox. Type ME1400 was first introduced in 1950.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
tc
m
h
a
g2
g3
-
h
k
g1

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
4.5
0.16
45
45
-2
0.80
0.20
5,000
0.24

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
-
250
100
-2
1.0
-
-
1.8
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated January 15, 2018.
shape:wide.glass.tube construction:pinch type:pentode age:1950.1960 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.g2 pin:5.g3 pin:6.- pin:7.h pin:8.k pin:tc.g1
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