A pentode transistor is any

transistor A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...

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 The point-contact transistor was the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. They worked in a group led by phys ...

. *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 describedUS Patent 4,104,673 August 1,1978
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Modern pentode transistors

*Triple emitter transistor in three input transistor-transistor logic gates. *Triple collector transistor in three output

integrated injection logic Integrated injection logic (IIL, I2L, or I2L) is a class of digital circuits built with multiple collector bipolar junction transistors (BJT). When introduced it had speed comparable to TTL yet was almost as low power as CMOS, making it ideal for ...

gates. *

Field effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the current through a semiconductor. It comes in two types: junction FET (JFET) and metal-oxide-semiconductor FET (MOSFET). FETs have three termi ...

having three gates.

References

{{Electronic components Transistor types