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EL821

Sensibly equivalent to:
6CH6 7D10 CV2127
    
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Type EL821 is a video output amplifier used in professional applications for driving TV or radar signals down (fairly) long cables. This exhibit is by Philips and made in Holland.
Sources specifically list it as a video amplifier for high definition television. Note the high value of gm, necessary in order to obtain reasonable gain and power output with wide-band signals, and for correct matching of video into coax cable. TV studio equipment racks used to be full of these valves.
The anode side view.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins, is 59 mm tall.
References: Datasheet & 1040.

 

Pin Connections
B9A
1
2
3
4
5
6
7
8
9
ic
g1
k
h
h
-
a
g2
g3

 

Absolute Maximum Operating Conditions
Beam Tetrode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
Pout
D
6.3
0.75
250
250
-4.5
40
6
50,000
11
3W
8.5%
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated April 01, 2014.
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