The EBF11 is a double diode pentode designed for use in superhet radio receivers. The pentode can be used as an RF, IF or audio amplifier. The diodes are for signal and AGC rectification.
The dome carries the identification. The case is steel under the paint.
The Footless base.
The wide metal tube envelope is 39 mm in diameter and, excluding the Footless base pins, is 49 mm tall.
Reference: Data-sheet. Type EBF11 was first introduced in 1940. See also1940 adverts.
