Sensibly equivalent¶ to:
The EBF89 features two signal diodes and a variable μ pentode in the one envelope and sharing a common cathode.
The variable μ characteristic is indicative of a device designed to have its gain controlled by an AGC system. This places this valve in service as a final IF amplifier and detector. The high impedance of the pentode supports the case for use with a tuned circuit connected to the anode.
Through the hole in the screen the three wire grids are visible. The cathode tube passes through a screen without any coating. Just below the top mica the tube is coated again and either side are the diode anodes.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 59 mm tall.
References: Data-sheet & 1040. Type EBF89 was first introduced in 1954. See also 1954 adverts.
Absolute Maximum Operating Conditions¶
Updated February 21, 2019.