Pentode transistor explained

A pentode transistor is any transistor having five active terminals.

Early pentode transistors

One early pentode transistor was developed in the early 1950s as an improvement over the point-contact transistor.

• A point-contact transistor having three emitters. It became obsolete in the middle 1950s.

Pentode field-effect transistors having 3 gates, similar to vacuum tube pentodes have also been described^[1]

Modern pentode transistors

• Triple emitter transistor in three input transistor-transistor logic gates.
• Triple collector transistor in three output integrated injection logic gates.
• Field effect transistor having three gates.

References

1. https://archive.today/20120701101306/http://151.207.240.23/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/search-adv.htm&r=1&p=1&f=G&l=50&d=ptxt&S1=4104673.PN.&OS=pn/4104673&RS=PN/4104673 US Patent 4,104,673 August 1,1978