Random number generator circuit

Try this: http://www.cryptography.com/public/pdf/IntelRNG.pdf

 

Pseudo-random using shift registers with EXOR feedback .
http://www.ee.iitb.ac.in/student/~shalini/ESD_EE616/course_project.pdf

 

Depending on what you want it for.. use google images to find white noise generator.

I know it's not in the spirit of the question but if you were building some sort of networked device you might be able to get your random numbers from a web site like this.. http://www.random.org/

 

Gambling machines use fluctuating dark currents to generate random seeds for a pseudorandom number generators.

random.org also a source of random numbers.

Claude.