▼ Menu

A45

 
See also:
Cosmos Advert, October 1927 - Cosmos A45 Box
    
Extras ▼

 

The Cosmos A45 is a bright emitter receiving triode that was introduced in April 1925 by Metro-Vick Supplies, a subsidiary of the Metropolitan Vickers Electrical Co Ltd. The first production had a metal base skirt and later types had the bakelite skirt as shown in the picture above. The M over V logo can also be seen as can the filament rating of 4.5 Volts at 0.6 Amps. Both versions employed the same 30 mm wide envelope.
The valve was a general purpose type with an amplification factor (μ) of nine. The control grid voltage range was between 0 and -6 Volts.
Looking obliquely at the valve the etched lettering and logo is easier to see. The filament is given as 4.5 Volts and 0.65 A. In practice a bright would be operated with just sufficient power for good reception as under running the filament extended its life. This exhibit was purchased from a picture showing a nickel base shell but in fact it is of the later plastic type. The filament is good and is a single vertical strand. The cosmos brand can be seen on the underside of the base shell.
The electrodes were visible at this inclined angle under the gettering. The helical grid is clearly visible and the single strand filament can also be seen clamped to the lower support.
See also A45 for our other example.
The wide glass tube envelope is 31 mm in diameter, and excluding the B4 base pins, is 92 mm tall.
References: 1003 Type A45 was first introduced in 1925.

 

Pin Connections
B4
1
2
3
4
a
g1
f
f

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
ra
gm
4.5
0.65
30-120
-6
20k
0.45
Updated December26, 2011.
Return to Main Index