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HD24

Sensibly equivalent to:
210DDT AR10 CV1308 CV2985 DDT2 L21DD TDD2A
    
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The HD24 is a directly heated double diode triode that would have been used in broadcast receivers, as detector, AGC detector and first audio amplifier. The metal paint is flaking off of the glass leaving little residue of the adhesive. Our other HD24 was made for the consumer market and has a plain envelope.
The HD24 has a lower filament consumption than the HD23 which itself was designed to lower the filament consumption and thus replace the HD21 and/or HD22. The HD24 has a lowest anode current rating of the series.
The classic envelope is 40 mm in diameter and, excluding the B5 base pins, is 98 mm tall.
References: Datasheet, 1040 & 1043. Type HD24 was first introduced in 1939.

 

Pin Connections
B5
1
2
3
4
5
tc
a
a(d1)
f(-)
f(+)
a(d2)
g1

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
2.0
0.1
150
-1.5
1.1
28,600
1.4
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated March 18, 2014.
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