TheAlgorithms/Python · error · ValueError

Inductance cannot be 0 or negative

Error message

Inductance cannot be 0 or negative

What it means

Raised by resonant_frequency() in electronics/resonant_frequency.py when inductance <= 0. The function computes f = 1/(2*pi*sqrt(L*C)), where a non-positive L makes the expression undefined (or a short/degenerate LC tank), so both L and C are required to be strictly positive; L is checked first.

Source

Thrown at electronics/resonant_frequency.py:35

    """
    This function can calculate the resonant frequency of LC circuit,
    for the given value of inductance and capacitnace.

    Examples are given below:
    >>> resonant_frequency(inductance=10, capacitance=5)
    ('Resonant frequency', 0.022507907903927652)
    >>> resonant_frequency(inductance=0, capacitance=5)
    Traceback (most recent call last):
      ...
    ValueError: Inductance cannot be 0 or negative
    >>> resonant_frequency(inductance=10, capacitance=0)
    Traceback (most recent call last):
      ...
    ValueError: Capacitance cannot be 0 or negative
    """

    if inductance <= 0:
        raise ValueError("Inductance cannot be 0 or negative")

    elif capacitance <= 0:
        raise ValueError("Capacitance cannot be 0 or negative")

    else:
        return (
            "Resonant frequency",
            float(1 / (2 * pi * (sqrt(inductance * capacitance)))),
        )


if __name__ == "__main__":
    import doctest

    doctest.testmod()

View on GitHub (pinned to f5988cc097)

Solutions

1. Pass a strictly positive inductance in henries, e.g. resonant_frequency(inductance=10, capacitance=5).
2. Use keyword arguments so L and C cannot be silently swapped.
3. Validate config values at load time: `if cfg.inductance <= 0: raise` with a message naming the config key.

Example fix

# before
resonant_frequency(inductance=0, capacitance=5)  # ValueError

# after
resonant_frequency(inductance=10, capacitance=5)

if not (inductance > 0):
    raise ConfigError("inductance must be > 0 henries")

def valid_lc(l: float, c: float) -> bool:
    return isinstance(l, (int, float)) and isinstance(c, (int, float)) and l > 0 and c > 0

try:
    name, freq = resonant_frequency(inductance=L, capacitance=C)
except ValueError as exc:
    raise SimulationConfigError(str(exc)) from exc

When it happens

Trigger: resonant_frequency(inductance=0, capacitance=5); passing a negative inductance such as -10; default-initialized variables (0.0) passed because a sensor or config value was never set.

Common situations: Simulation setups where a component is omitted and defaults to 0; parsing configs where the inductance key is missing and a helper returns 0; unit-scale mistakes (e.g. entering 0 because the value was expressed in a scaled unit elsewhere).

Related errors

• Capacitance cannot be 0 or negative
• Capacitor at index {index} has a negative or zero value!
• You cannot supply more or less than 2 values
• Electron concentration cannot be negative in a semiconductor
• Hole concentration cannot be negative in a semiconductor

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/2647c403bf87b80d. Report an issue: GitHub.