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N77

Sensibly equivalent to:
6AM5 7D9 CV136 EL91 V887
    
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The Osram N77 is a miniature audio output pentode. In single ended configuration it will produce 1.4 Watts, suitable for a small broadcast receiver.
If used in push pull an output of 4 Watts is possible, but this valve was not expected to be used for hi-fi and for a radiogram there would be sufficient space to specify a physically larger valve. Output valves in the B7G base format ran very hot and not ideal if space existed for a larger envelope.
The control grid has radiating fins.
The thin glass tube envelope is 18 mm in diameter and excluding the B7G base pins, is 46 mm tall.
References: Datasheet & 1040. Type N77 was first introduced in 1953.

 

Pin Connections
B7G
1
2
3
4
5
6
7
g1
k
h
h
a
ic
g2

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
Pout
6.3
0.2
250
250
-13.8
16
2.4
130k
2.6
1.4W
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated January 18, 2013.
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