I’m trying to solve the following DAE:

The solution obtained from a simulator is:

Nevertheless, we want to solve the model with `DifferentialEquations.jl`

, and I’ve tried with the following code:

```
using DifferentialEquations, Plots
f = 10E3
ω = 2*π*f
n = 1
C = 0.01E-6
VT = 25E-3
IS = 1E-6
A = 1.0
R = 10E3
function func(out, du, u, p, t)
V0, IR = u
dV0, _ = du
out[1] = C*dV0 - IR
out[2] = (A*sin(ω*t) - V0 - n*VT*log(1+IR/IS)) - R*IR
end
B = A*ω/R/(1+n*VT/R/IS)
u₀ = [0, 0.0] # V0, IR
du₀ = [0, B] # dV0, dIR
dvars = [true, false]
tspan = (0, 2E-3)
prob = DAEProblem(func, du₀, u₀, tspan, differential_vars=dvars);
```

It gives the following error:

```
sol = solve(prob)
DomainError with -0.33407903800223493:
log will only return a complex result if called with a complex argument. Try log(Complex(x)).
```

What do you suggest to tackle this problem?