At this point students should know that BJT works on current. A circuit
supplying current for the BJT is called a biasing circuit. The first biasing technique
we will study is fixed bias.
Says we would like to supply base current (IB) approximately 1.5 uA to the
2N2222. The typical current gain of 2N2222 is 200, thus we could get IC
approximately around 0.3 mA.