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3A4

Sensibly equivalent to:
CV807 CV2390 DL93 E1485
    
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The 3A4 miniature output pentode is specified for both audio and transmitter use. For a small dry battery valve 1.2 Watts output in the HF range would be quite an achievement.
The RCA logo and a view of the two wire grids. The metal structure inside the anode cylinder is the beam plate. This pentode is made as a beam tetrode.
The country of origin.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 46 mm tall.
References: Datasheet & 1040. Type 3A4 was first introduced in 1945.

 

Pin Connections
B7G
1
2
3
4
5
6
7
f-
a
g2
g1
fct
a
f+

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
mAa
mAs
Pdiss
Pout
freq
1.4
0.2
150
135
18.3
6.5
2W
1.2W
50MHz

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAs
ra
gm
Pout
D
1.4
0.2
150
90
-8.4 mAa_13.3
2.2
100,000
1.9
0.7
6%
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated November 28, 2014.
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