Sensibly equivalent¶ to:
The EB91 is a double signal diode. Mullard separate rectifier diodes and signal diodes in their naming convention. The full wave rectifier being given the letter Z, the twin diodes the letter B.
The EB91 dates from 1949 but the American 6AL5 was produced in 1946. Prior to the EB91 there was the EB41 all glass valve and the EB34.
The two valves are completely separate flat structures separated by a plate screen. This clearly shows the signal usage, where it is important to keep RF isolation.
Mullard designed these diodes for vision and sound detection. Additionally they are recommended for limiting and DC restoration. Each section is internally screened.
The most common fault with the EB91 design is heater to cathode leakage.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 47 mm tall.
References: Datasheet 1040 & 3002. Type EB91 was first introduced in 1949.
Absolute Maximum Operating Conditions¶
Updated January 05, 2013.