Hopfield networks, named as after their inventor John Hopfield (1982), are entirely connected feedback Networks. The neurons in Hopfield networks are epitomized by the following: binary or bivalent input signals, binary or bivalent output signals, very simple summation function, or hard-limited threshold activation function. There are actually substitute variants of realizations of a Hopfield network. Every neuron j, j = 1, 2,...,n in the network is connected going back to every other one, with the exception of itself. Input patterns xj are offered to the external inputs Ij and cause activation of the external outputs.