*4.54 In the circuit shown in Fig. P4.54, diodes D1 through D4 are identical, and each exhibits a voltage drop of 0.7 V at a 1-mA current. (a) For small input signals (e.g., 10-mV peak), find the small-signal equivalent circuit and use it to determine values of the small-signal transmission vo/vi for various values of I: 0 µA, 1 µA, 10 µA, 100 µA, 1 mA, and 10 mA. (b) For a forward-conducting diode, what is the largest signal-voltage magnitude that it can support while the corresponding signal current is limited to 10% of the dc bias current? Now, for the circuit in Fig. P4.54, for 10-mV peak input, what is the smallest value of I for which the diode currents remain within ±10% of their dc values? (c) For I = 1 mA, what is the largest possible output signal for which the diode currents deviate by at most 10% of their dc values? What is the corresponding peak input? What is the total current in each diode? Figure P4.54 (a) 0 V/V; 0.167 V/V; 0.667 V/V; 0.952 V/V; 0.995 V/V; 0.9995 V/V; (b) |ΔvD| < 2.5 mV; I ≥ 5 A; (c) 1 V; 1.005 V; iD1 = iD4 = 0.45 mA; iD2 = iD3 = 0.55 mA;