I search transistor equivalent circuit, like http://www.globalspec.com/reference/25593/203279/7-5-diode-mixers for diode. How to replace one transistor npn or pnp with nonlinear resistors and capacitors? What are parameters ? (for diode was kT/e = 26 mV, where k is Boltzmann constant, T is 300K, e is elementary charge) Spice has parameters of transistors, how use it? how use http://www.diodes.com/_files/spicemodels/all.txt ? What capacitance have CMOS transistors on VLSI Integrated circuit?