RLC circuit tuner

I got bored of calculating resonances by hand, so here's a tuner for an RLC circuit. The transfer function is the ratio of the voltage across $R_L$ to the input voltage.

 

 

	import matplotlib as mpl
	#mpl.rc('text', usetex = True)
	#mpl.rc('font',**{'family':'serif','size':16,'weight':'bold','serif':['Palatino']})
	from __future__ import division
	import numpy as np
	from numpy import pi
	import matplotlib.pyplot as plt
	from matplotlib.widgets import Slider, Button, RadioButtons
	def ser(A,B): return A+B
	def par(A,B): return A*B/(A+B)
	def H(f,L,C,R,RL):
	# Resonant circuit
	omega = 2*pi*f
	X_L = 1j*omega*L
	X_C = 1/(1j*omega*C)
	Z0 = par(par(X_L,X_C),RL)
	return Z0/(R+Z0)
	# Random initial values
	L = 1e-3 # H
	C = 1e-3 # F
	R = 1e1 # Ohms
	RL = 1e3 # Ohms
	f = np.arange(0.1,1000,0.1)
	fig = plt.figure(figsize=(9,4.5))
	ax1 = fig.add_subplot(111)
	ax2 = ax1.twinx()
	lmag, = ax1.plot(f,np.abs(H(f,L,C,R,RL)))
	lphase, = ax2.plot(f,np.angle(H(f,L,C,R,RL)),'g')
	ax2.grid(which='major',axis='y')
	ax2.set_ylabel("Phase[H(f)] [rad]",color='g')
	ax1.set_ylabel("Magnitude, |H(f)|",color='b')
	ax1.set_xlabel("Frequency, f [Hz]")
	#plt.tight_layout()
	fig.subplots_adjust(bottom=0.11*4)
	#plt.subplots_adjust(left=0.10)
	#plt.subplots_adjust(right=1.00)
	ax = []
	slider = []
	axcolor = 'lightgoldenrodyellow'
	class Parameter:
	def __init__(self,label,limit,value):
	self.label = label
	self.limit = limit
	self.value = value
	params = [ Parameter('log10 L',[-6,-1],-3), \
	Parameter('log10 C',[-9,-2],-4), \
	Parameter('log10 R',[0,8],2), \
	Parameter('log10 RL',[0,9],6)]
	for i in range(len(params)):
	ax.append( plt.axes([0.25, 0.26-0.05*i, 0.65, 0.03], axisbg=axcolor) )
	slider.append( Slider(ax[i],params[i].label,params[i].limit[0],params[i].limit[1],valinit=params[i].value) )
	def update(val):
	L = 10**slider[0].val
	C = 10**slider[1].val
	R = 10**slider[2].val
	RL = 10**slider[3].val
	lmag.set_ydata( np.abs(H(f,L,C,R,RL)) )
	lphase.set_ydata( np.angle(H(f,L,C,R,RL)) )
	fig.canvas.draw_idle()
	for i in range(len(params)): slider[i].on_changed(update)
	update(0)

view raw RLCtuner.py hosted with ❤ by GitHub