>I have posted a true hardware-based random generator for the PIC. It uses
>a base-emitter junction of a Ge-PNP transistor as a noise source and a
>two-stage op. amp amplifies it to the TTL level. I attach it for your
>convenience (1,5 k only).


Useful circuit.
Note that the transistor used is somewhat critical if 5 volts is to be
used - the junction on some (many?) silicon transistors will not exhibit the
required zener action until about 9 volts is applied - which is no doubt why
a germanium device was specd. Experimentation may reveal some silicon
transistors which will work OK here.

Note that an NPN can also be used if the transistor base is taken to ground
and the 4K7 taken to Vcc.




      Russell McMahon
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