TheAlgorithms-Python

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# https://en.wikipedia.org/wiki/Wheatstone_bridge
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from __future__ import annotations
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def wheatstone_solver(
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    resistance_1: float, resistance_2: float, resistance_3: float
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) -> float:
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    """
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    This function can calculate the unknown resistance in an wheatstone network,
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    given that the three other resistances in the network are known.
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    The formula to calculate the same is:
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    ---------------
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    |Rx=(R2/R1)*R3|
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    ---------------
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    Usage examples:
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    >>> wheatstone_solver(resistance_1=2, resistance_2=4, resistance_3=5)
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    10.0
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    >>> wheatstone_solver(resistance_1=356, resistance_2=234, resistance_3=976)
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    641.5280898876405
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    >>> wheatstone_solver(resistance_1=2, resistance_2=-1, resistance_3=2)
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    Traceback (most recent call last):
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        ...
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    ValueError: All resistance values must be positive
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    >>> wheatstone_solver(resistance_1=0, resistance_2=0, resistance_3=2)
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    Traceback (most recent call last):
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        ...
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    ValueError: All resistance values must be positive
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    """
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    if resistance_1 <= 0 or resistance_2 <= 0 or resistance_3 <= 0:
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        raise ValueError("All resistance values must be positive")
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    else:
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        return float((resistance_2 / resistance_1) * resistance_3)
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if __name__ == "__main__":
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    import doctest
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    doctest.testmod()
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