a) By using the constant voltage drop model (with Voo-0.7V) for the diodes, find IDI, ID2, D3, ID4, VDI, VD2, VD3, VD4 for these two cases: i) V-12V, ii) V--9V b) By using the ideal diode model, find the Vi voltage which satisfies I = -3mA. c) By using the exponential diode model, calculate the Vi voltages which satisfy, i) I=1.5mA ii) I = -2.5mA. D RA RB It VIOD DAY Diodes: Is Is3-110-3A, Isz-Is4=210-4A (VT-25.9mV), Resistors: R-3k2, RB-5k