🚀 go-pugleaf

I am looking for a "black box" circuit that has the product transfer
function:

Output voltage = 0.5 ( 1 + tanh ( Input voltage / "Gain" ) )

	       = 1 / ( 1 + exp ( -2 * Input voltage / "Gain" ) )

When plotted, this function looks like an elongated S

When IV = - infinity, OV = 0
When IV = + infinity, OV = 1
When IV = 0         , OV = 0.5

By the way, this question arose in connection with a neural network
problem.

Thanks.

Krishna Ambati
krishna@aecom.uucp