Nick Bryant (bryant@mpr.ca) wrote: 
: I am now looking for a simple circuit which will generate a white 
: noise signal, suitable for the AUX input of a spare amplifier I own. 
: Does anyone have a _proven_ circuit they would care to share? 
 
Yes, I have a _proven_ circuit. 
 
 
	An easy way to realize white noise 
	================================== 
 
There is a very easy way to realize a white-noise-circuit. 
Take a bipolar npn-transistor and a resistor. That's all. 
The trick is, you must need the inverse basis-emitter- 
breakdownvoltage (about 7V) as following circuit shows:  
 
        |-----------------------------------------o  +15V 
	| 
	R1 = 470 k-Ohm 
        | 
	|------------------> U-noise = 5 - 20 mV  
	| 
      e \|	 	     To amplify U-noise take a highimpedance-opamp, 
      b  |----  BC107        like a bi-fet-type is, as example LF356, TL071. 
      c /|    |		    
	      | 
   	      | 
	      |----------------------------------o   GND 
 
	With other transistor-type it can be you must change the resistor 
	R1 between about 100k-Ohm and 1M-Ohm for best results. 
 
So I hope I can help you. If you have more questions write to my 
mailbox please 
 
Thomas 
 
  
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