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DD4D

 
    
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The Tungsram DD4D is a pair of indirectly heated signal diodes in a single envelope.
The central screen is mounted at right angles to the diode anodes and is connected to pin 1.
Face view of the pair of diodes.
The heaters are double helixes to minimise the external hum field.
The classic envelope is 38 mm in diameter and, excluding the B7 base pins, is 88 mm tall.
Reference: 1043. Type DD4D was first introduced in 1938.

 

Pin Connections
B7
1
2
3
4
5
6
7
s
a(2)
k(2)
h
h
k(1)
a(1)

 

Absolute Maximum Operating Conditions
Diode
Vh
Ah
Va
mAa
4.0
0.4
100
4.0
Updated August 20, 2019.
shape:classic construction:pinch type:double.diode age:1930.1940 base:b7 heater:4.0v pins:7 pin:1.s pin:2.a(2) pin:3.k(2) pin:4.h pin:5.h pin:6.k(1) pin:7.a(1)
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