▼ Menu

MPT4

Sensibly equivalent to:
7A2 MP/Pen Pen4VA
See also:
The Azide Process - 1935 Advert
    
Extras ▼

 

M-OV had trouble designing the MPT4. Not only did it take them a clear two years to produce technically successful copies of Mazda's landmark AC/Pen but thereafter they had to redesign it several times (including the beam tetrode version MKT4) over the next 5 or 6 years.
This exhibit has the original screw-on side cap. See also MPT4 for more details.
The cylindrical anode and the rear of the Marconi brand label.
The suppressor grid can be seen to be connected to the cathode at the top of the valve.
The lettering is etched into the dome. The inner two grids are shaped around the cathode whereas the suppressor grid is helical and placed near to the anode.
A closer view of the inner grids.
The balloon envelope is 56 mm in diameter and, excluding the B5 base pins, it is 112 mm tall.
References: Data-sheet & 1043. Type MPT4 was first introduced in 1931.

 

Pin Connections
B5
1
2
3
4
5
sc
a
g1
h
h
k,g3
g2

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
4.0
1.0
250
200
-10.5
32.0
5.5
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated July 21, 2020.
shape:balloon construction:pinch type:pentode age:1930.1940 base:b5 heater:4.0v pins:5 pin:1.a pin:2.g1 pin:3.h pin:4.h pin:5.k.g3 pin:sc.g2
Return to Main Index