# Ltspice nonlinear dependent source

###### Dan avidan illness

##### Drag and drop react builder

###### John caldwell england

LTspice will replace the VCVS with a B-source, ... Now the problem is creating a control voltage, that is nonlinear in its nature, and which needs to vary the resistance of the VCSW according to V(b). ... and the differences compared to a true division are dependent on it, but they are not large. ...Dear All, I want to model a nonlinear resistor behavior whose V-I relation is as V=R1*I+R2*I^3 = (R1+R2*I^2)I. I face this problem when I try to establish a equivalent circuit model for a nonlinear mechanical system. Well, the one in the link works now. Turns out one shall not get too close to very low values where LTSpice has a hard time. At least it heats my office :-) LTSpice Voltage Controlled Voltage Source (VCVS) We have a divide-by-2 voltage divider followed by the VCVS which multiplies the input voltage, Vg with a gain factor of 10 $$\ V_g = {1 \over 2} * V1 = {1 \over 2} * 1 = 0.5V $$ $$\ V_{out} = 10*V_g = 10*0.5 = 5V $$ References: LTSpice Prof. Jacob Baker cmosedu.comA model's ability to predict the nonlinear behavior of a PA transistor is based on several key aspects: The representation of the voltage-dependent current source (I ds) Voltage-dependent capacitances (primarily gate-to-source C gd and drain-to-source C gs) Voltage-dependent diode models, which are related to the prediction of breakdown voltageThe nonlinear capacitors and current sources are combined to produce the time dependent electri-cal behavior of the device. A device circuit sche-matic is shown in Figure 5. The main components are the voltage controlled current source, ID, Non-linear capacitors, C GD, C GS, and C SD., and input resis-tors R S, R D, and R G. Using the Model