RC circuit simulation with rl

import matplotlib.pyplot as plt
import tkinter as tk


def plot_rc_circuit(R, C, t_max, dt):
  t = []
  vc = []
  ic = []

  t.append(0)
  vc.append(1)
  ic.append(-1)

  for i in range(int(t_max / dt)):
    t.append(t[i] + dt)
    vc.append(vc[i] - dt / (R * C) * vc[i])
    ic.append(-vc[i] / R)

  plt.plot(t, vc, 'r', t, ic, 'b')
  plt.show()


def plot_rl_circuit(R, L, t_max, dt):
  t = []
  vl = []
  il = []

  t.append(0)
  vl.append(1)
  il.append(-1)

  for i in range(int(t_max / dt)):
    t.append(t[i] + dt)
    vl.append(vl[i] - R / L * dt * il[i])
    il.append((vl[i] - vl[i - 1]) / L * dt)

  plt.plot(t, vl, 'r', t, il, 'b')
  plt.show()


def set_variables():
  root = tk.Tk()
  root.title("Circuit Variables")

  tk.Label(root, text="R (ohm)").grid(row=0, column=0)
  tk.Label(root, text="C (farad)").grid(row=1, column=0)
  tk.Label(root, text="L (henry)").grid(row=2, column=0)
  tk.Label(root, text="t_max (second)").grid(row=3, column=0)
  tk.Label(root, text="dt (second)").grid(row=4, column=0)

  e1 = tk.Entry(root)
  e2 = tk.Entry(root)
  e3 = tk.Entry(root)
  e4 = tk.Entry(root)
  e5 = tk.Entry(root)

  e1.grid(row=0, column=1)
  e2.grid(row=1, column=1)
  e3.grid(row=2, column=1)
  e4.grid(row=3, column=1)
  e5.grid(row=4, column=1)

  tk.Button(root, text='Plot RC Circuit',
        command=lambda: plot_rc_circuit(float(e1.get()), float(e2.get()), float(e4.get()), float(e5.get()))).grid(
    row=5, column=0, pady=4)
  tk.Button (root, text='Plot RL Circuit', command=lambda: plot_rl_circuit(float(e1.get()), float(e3.get()), float(e4.get()), float(e5.get()))).grid(row=5, column=1, pady=4)
  tk.mainloop()

set_variables()