A historic vacuum tube containing eight distinct electrodes, typically a cathode, an anode, and six grids. These complex tubes were primarily used in early radio receivers as frequency converters or mixers, allowing a single component to handle both local oscillation and mixing.
Heard on the job
I found an old octode in the parts bin that was originally used as a frequency converter in a superheterodyne receiver.
Related terms
Vacuum tube
An evacuated glass or metal envelope containing electrodes used to control electron flow.
Triode
A three-electrode vacuum tube capable of amplifying electronic signals.
Superheterodyne
Describing a receiver architecture that converts incoming radio frequencies to a fixed intermediate frequency for easier filtering and amplification.