def equilibrium_carrier(N, ni=8600000000.0):
    """Return the majority and minority carrier concentrations (cm-3) of a semiconductor at equilibrium
    where N is the doping level (cm-3) and ni is the intrinsic carrier concentratoin (cm-3)
    Strictly N and ni just have to be in the same units but (cm-3) is almost always used."""
    majority = N
    minority = N / ni ** 2
    return majority, minority
