[sdiy] "zener" noise

[Roy J. Tellason]

On Monday 11 July 2005 03:06 am, Mikael Mørup wrote:
> Citat "Roy J. Tellason" <rtellason at blazenet.net>:
> > I'm contemplating a circuit that uses a reverse-biased base-emitter
> > junction as a noise source.  How would these compare with just
> > using a zener diode of a similar voltage range (around 7 or 8 volts)?
> >
> > Can the same sort of thing be done with a germanium device rather than
> > silicon?
>
> I build Ray Wilsons "pink enough for me" module and it calls for a setup
> like the one you refer to, i used a Zener in stead and it works very well.
>
> I woldn't know about the germanium diode though.

Interesting,  in that the circuit calls for a 2N2712 transistor as a noise 
source,  which is the same part called for in the magazine article I used in 
the first place.  I did a little bit of playing around with that portion of 
it,  using a socket for the transistor in the noise source part of it,  and a 
great many other parts worked in there just as well.  I don't think it used 
anywhere near as high a value of resistor,  though, as 4.7M -- I think it 
used something like 100K.