11/1/2004 The MOSFET as an Amp and Switch.doc 1/14. Jim Stiles The Univ. of Kansas Dept. of EECS. The MOSFET as an. Amp and Switch. Consider this simple MOSFET circuit: A: Actually, this circuit is a fundamental electronic. device! To see what this circuit does, we need to. determine its transfer function v. OI=fv( ). A: Same as with junction diodes—we determine the output v.