MOSFET is Metal Oxide Semiconductor Field Effect Transistor.

IGFET Insulated Gate Field Effect Transistor.

But these expressions are practically synonyms.

Field Effect Transistor

A: basically a silicon bar where the conduction is controlled by a field since there is no connection to the gate the impedance is very high

Its a Transistor used in JFET (Junction Field Effect Transistor)

The transistor was created by researchers at the university of Geneva.

"The first patent for a field-effect transistor principle was filed in Canada... 1925. In 1934 German physicist Dr. Oskar Heil patented another field-effect transistor."

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