7.51 Figure P7.51 shows a transistor with the collector connected to the base. The bias arrangement is not shown. Since a zero v BC implies operation in the active mode, the BJT can bereplaced by one of the small-signalmodels of Figs. 7.24 and 7.26. Use the model of Fig. 7.26(b) and show that the resulting two-terminal device, known as a diode-connected transistor, has a small-signal resistance r equal to re.