9.30 An npn differential pair employs transistors for which v BE = 690 mV at iC = 1 mA, and β = 50. The transistors leave the activemode atv CE ≤ 0.3 V. The collectorresistors RC = 82 k, and the power supplies are ±1.2 V. The bias current I = 20 μA and is supplied with a simple current source. (a) For vB1 = vB2 = VCM = 0 V, find VE, VC1, and VC2. (b) Find the input common-mode range. (c) If vB2 = 0, find the value of vB1 that increases the current in Q1 by 10%.