**C H A P T E R**

Another distinct difference between the analysis of BJT and FET
transistors is that the input controlling variable for a BJT transistor
is a current level, while for the FET a voltage is the controlling
variable. In both cases, however, the controlled vari-able on the output
side is a current level that also defines the important voltage lev-els
of the output circuit.

The general relationships that can be applied to the dc analysis of
all FET am-plifiers are

**253**

**6.2** **FIXED-BIAS CONFIGURATION**

The simplest of biasing arrangements for the *n*-channel JFET
appears in Fig. 6.1. Re-ferred to as the fixed-bias configuration, it is
one of the few FET configurations that can be solved just as directly
using either a mathematical or graphical approach. Both methods are
included in this section to demonstrate the difference between the two
philosophies and also to establish the fact that the same solution can
be obtained us-ing either method.