One method of increasing the small-signal output resistance of an NPN BJT current source is to place a resistor in the emitter (RE). The equivalent circuit of such a current source is shown in Figure 48(a). The low-frequency, small-signal hybrid-p model of the BJT in this source is shown in Figure 48(b). The parameter for this model are given as
gm= 80 mS
rp= 2.5 K O
ro= 250 K O
Using these parameters and the value for RB shown on the schematic, calculate the value for the small-signal Thevenin's output resistance RTH observed from the collector to ground under the conditions of
(a) RE= 0O, and
(b) RE= 1KO
Which of the above conditions provides the larger value of RTH? Express your solution in numerical format.