Create active_low_pass_filter.py

examples/filter/active_low_pass_filter.py

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+from PySpice.Spice.Netlist import SubCircuitFactory
+from PySpice.Unit import *
+from PySpice.Spice.Netlist import Circuit
+
+class OpAmp(SubCircuitFactory):
+    NAME = 'opamp'
+    NODES = ('non_inverting_input', 'inverting_input', 'output')
+
+    def __init__(self):
+        super().__init__()
+        self.VoltageControlledCurrentSource('input', self.gnd, 'n1', 'non_inverting_input', 'inverting_input', transconductance=100)
+        self.Resistor('1', 'n1', self.gnd, resistance=1323@u_kOhm)
+        self.Capacitor('1', 'n1', self.gnd, capacitance=30@u_pF)
+        self.VoltageControlledVoltageSource('out', 'output', self.gnd, 'n1', self.gnd, voltage_gain=1)
+
+
+# Create a new circuit
+circuit = Circuit('Low Pass Filter')
+
+# Add the opamp to the circuit
+circuit.subcircuit(OpAmp())
+
+# Define the input voltage
+
+# Define the input voltage
+circuit.SinusoidalVoltageSource('1', circuit.gnd, 'n2', amplitude = 5@u_V, frequency = 200@u_Hz)
+circuit.SinusoidalVoltageSource('2', 'n2', 'n3', amplitude = 1@u_V, frequency = 5@u_Hz)
+
+# Connect the opamp
+circuit.X('opamp', 'opamp', 'non_inverting_input', 'inverting_input', 'nout')
+
+# Define the resistors and capacitors for the low pass filter
+circuit.R(1, 'n3', 'inverting_input', 10@u_kΩ)
+circuit.R(2, 'inverting_input', 'nout', 1000@u_kΩ)
+circuit.C(1, 'inverting_input', 'nout', 0.0159@u_uF)
+
+# Ground non-inverting input
+circuit.R(3, 'non_inverting_input', circuit.gnd, 1@u_pOhm)
+
+# Connect the output
+circuit.R('load', 'nout', circuit.gnd, 1@u_MΩ)
+
+simulator = circuit.simulator(temperature=25, nominal_temperature=25, reltol=1e-12)
+analysis = simulator.transient(step_time=0.1@u_ms, end_time=2@u_s)
+
+import matplotlib.pyplot as plt
+
+plt.figure(figsize=(20, 10))
+plt.plot(u_ms(analysis.time), analysis['n3'], label='Input Voltage [V]')
+plt.plot(u_ms(analysis.time), analysis['nout'], label='Output Voltage [V]')
+plt.legend()
+plt.plot()