== Comparing High Frequency & Low Frequency BJT Models ==
High frequency transistors are typically characterized by their S-[[parameters]]. The manufacturer data sheets of RF transistors usually contains tables of measured S-parameter data for various DC bias operating points over a certain range of frequencies. [[RF.SpiceA/D]] has a large number of RF bipolar junction transistor (BJT) models with measured S-parameter tables for different combinations of collector-emitter voltages (VCE) and collector currents (IC). Most of [[RF.Spice]]'s RF BJT devices also have counterpart standard BJT model that can be used for DC operating point analysis. The figures below shows the property dialog of the standard BJT model of BFG193 next to the property dialog of the RF BJT model of BFG193 measured at VCE = 10V and IC = 10mA. You will use this transistor for the amplifier design of this tutorial lesson.
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