Pyvolt makes circuit specification and simulation easy.

Install pyvolt using pip install -e . after cloning the repository.

Import pyvolt using import pyvolt as pv and import pyvolt.components as comp.

circuit = pv.Circuit()

Create a VoltageSource, Resistor, Diode, Switch, or Transistor and add it to the circuit. Use of Python's walrus (:=) operator is optional, but enables users to create and add components in one line.

circuit.add(voltage_source := comp.VoltageSource(name="V", v=5))
circuit.add(resistor := comp.Resistor(name="r1", ohm=150))
circuit.add(diode := comp.Diode(name="LED", v_f=2))

Pyvolt uses the >> operator to connect components instead of defining nodes explicitly:

voltage_source.vplus >> resistor.n1
resistor.n2 >> diode.anode
diode.cathode >> voltage_source.vminus

The circuit's ground is set by connecting it to any other component terminal. The node connected to the circuit ground is defined as having a voltage of zero.

circuit.gnd >> voltage_source.vminus

circuit.compile()

Here is the output of circuit.compile() on the circuit defined in this tutorial:

Compiled circuit
----------------
Node 0: v=5.0
    V.vplus: i=0.02
    r1.n1: i=-0.02
Node 1: v=2.0
    LED.anode: i=-0.02
    r1.n2: i=0.02
Node 2: v=0.0
    V.vminus: i=-0.02
    LED.cathode: i=0.02
    Ground.gnd: i=0.0
----------------

We interpret this output as follows:

• The node with V.vplus and r1.n1 has voltage 5V, with 20 milliamps of current flowing from V.vplus into r1.n1
• The node with LED.anode and r1.n2 has voltage 2V, with 20 milliamps of current flowing from r1.n2 to LED.anode
• The node with V.vminus, LED.cathode, and Ground.gnd has voltage 0V, with 20 milliamps of current flowing from LED.cathode to V.vminus

Pyvolt's convention is positive currents flowing out of components and negative currents flowing into components.

After a circuit has been compiled, we can use the inspect_voltage and inspect_current methods:

print("V before diode:", circuit.inspect_voltage(diode.anode))  # V before diode: 2.0
print("I before resistor:", circuit.inspect_current(resistor.n1))  # I before resistor: -0.02

We can define custom components by calling the new_node_ref(name) method inside of Component classes for each connection the component has. We can set the target voltage or current of a node or branch by calling set_voltage or set_current on the node reference, respectively.

class Arduino(pv.Component):
    def __init__(self, name: str = "", n_pins: int = 5):
        super().__init__(name)
        self.pin_connections: list[pv.NodeRef] = [self.new_node_ref(f"pin{i}") for i in range(n_pins)]
        self.gnd_connection = self.new_node_ref("gnd")

    def pin(self, pin):
        return self.pin_connections[pin]

    @property
    def gnd(self):
        return self.gnd_connection

    def pin_on(self, pin):
        self.pin_connections[pin].set_voltage(5)

    def pin_off(self, pin):
        self.pin_connections[pin].set_voltage(0)

Then, we can use it just like any other component:

circuit = pv.Circuit()

circuit.add(arduino := Arduino(name="arduino", n_pins=2))
circuit.add(r2 := comp.Resistor(name="r2", ohm=300))

arduino.pin(0) >> r2.n1
# ...