Sensibly equivalent¶ to:
The EBF89 features two signal diodes and a variable μ pentode in the one envelope and sharing a common cathode. The diode anodes are small plates placed either side of an extended cathode tube.
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.
The diode anodes are small strips of metal placed either side of the cathode tube. The cathode tube is un-coated as it leaves the top mica but a small length of coating is applied to the segment that sits between the diode anodes.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 59 mm tall.
References: Data-sheet & 1040. Type EBF89 was first introduced in 1954.
Absolute Maximum Operating Conditions¶
Updated January 26, 2016.