D 8.94 If the pnp transistor in the circuit of Fig. P8.94 is characterized by its exponential relationship with a scale current IS, show that the dc current I is determined by IR = VT ln(I/IS). Assume Q1 and Q2 to be matched and Q3, Q4, and Q5 to be matched. Find the value of R that yields a current I = 100 µA. For the BJT, VEB = 0.7 V at IE = 1mA.