The DDT215 is a battery double diode triode for use in superhet receivers. The diodes form the detector and AGC rectifier and the triode would be used as the first audio voltage amplifier.
The envelope is covered with metalising paint and the connection to the coating can be seen by the base.
The classic envelope is 39 mm in diameter, and excluding the B5 base pins is 104 mm tall.
Reference: 1043. Type DDT215 was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated December04, 2014. shape:classic construction:pinch type:double.diode.triode age:1930.1940 base:b5 heater:2.0v pins:5 pin:1.a pin:2.a(d1) pin:3.f(-) pin:4.f(+) pin:5.a(d2)