def wheastone(V_0, R1,R2,R3,R4):
    """
    Wheastone formula function

    Params : 
        - V_0 working voltage
        - R1, R2, R3, R4 the resistances
    """

    Vs = V_0 * (R4/(R1+R4)-R3/(R2+R3))

    return Vs