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Pen25

Sensibly equivalent to:
BVA162 CV65 Pen24
See also:
Mazda Pen25 Advert - CV65 short entry
    
Extras ▼

 

The 1938 Pen25 battery output pentode from Mazda was designed for domestic broadcast receivers. The filament was to be run from accumulators and the 0.15 Amp filament current would have assisted in prolonging the accumulator life.
The on-going marketing of the Pen25 is one of Mazda's post-war anachronisms. Not only was it obsolete in concept, since it was oversized compared to the B7G types by then available for all-dry portables and there was little market for new 2 V battery 'household' radios, but it was also fitted with the new Mazda Octal base which made it incompatible with anything else, including the American International Octal which everyone else was using. This was the beginning of a slow decline in the fortunes of the one-time British market leader.
See also Pen25 for more information.
The three filament tension springs are visible above the top mica.
The inner grids are nearly flat across the filament.
The filament is three inverted V's. The anode is a bright oval cylinder. The suppressor grid is an oval to match the anode. The dome carries the identification.
The classic envelope is 32 mm in diameter and, excluding the MO base pins, is 71 mm tall.
References: Datasheet & 1040. Type Pen25 was first introduced in 1938.

 

Pin Connections
MO
1
2
3
4
5
6
7
8
f(-)
-
a
g2
g1
-
-
f(+)

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
Pout
D
2.0
0.15
120
120
-3.6
5
1
0.35M
3.0
0.4W
16%
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated January 23, 2018.
shape:classic construction:pinch type:pentode age:1940.1950 base:mo heater:2.0v pins:8 pin:1.f(-) pin:2.- pin:3.a pin:4.g2 pin:5.g1 pin:6.- pin:7.- pin:8.f(+)
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