Determine if the circuit shown in <image 1> is in saturation.
['yes, saturation', 'no, not in saturation']
The base current is

                                           IB = [{vi - VBE(ON)} / {RB}]

                                                = [(4 - 0.7) / 22] = 0.15mA

                        Collector current at saturation is

                                      IC(sat) = [(VCC - Vsat) / (RC)]

                                                = [(4 - 0.2) / 1] = 3.8mA

                        The valu of hFE(sat) is determined from

                                    hFE(sat) = [IC(sat) / IB]

                                                = (3.8 / 0.15) = 25.3

                        hFE = 100, so hFE(sat) < hFE.

                        The transistor, therefore, is in saturation. If the cir\xadcuit was active, collector

                        current would be IC = hfeIB = 100 * .15 = 15mA. However, IC cannot rise

                        above 3.8mA, no matter how much IB is increased. This is what is meant

                        by saturation.