Sensibly equivalent¶ to:
The DDL4 is a double signal diode that dates from 1937. The diodes are indirectly heated and share a common cathode.
See also the 1934 220DD battery double diode from Cossor.
The balloon envelope is 29 mm in diameter and, excluding the B5 base pins, is 74 mm tall.
References: 1043. Type DDL4 was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated April 04, 2015. shape:balloon construction:pinch type:double.diode age:1930.1940 base:b5 heater:4.0v pins:5 pin:1.a pin:2.a pin:3.h pin:4.h pin:5.k