class MOSFET:
    def __init__(self,params=None,terminals=None):

        # Params
        if params is None:
            self._params_ = {'BV':20,
                             'Vth':1.0,
                             'gm':1e-2}
        else:
            self._params_ = params

        # Terminals
        if terminals is None:
            self._terminals_ = {'source':0.0,
                        'drain':0.0,
                        'gate':0.0}
        else:
            self._terminals_ = terminals