Greg_G wrote:A germanium diode has a Vf of about 0.3 volts, so wouldn't 3 in series limit the voltage swing to about 0.9 volts ?.
Yes,that's true,however,the test signal level of 14V,which I quoted,is the signal level coming from the Function Generator before it gets clipped by the diodes,to measure this,I had to disconnect the signal from the circuit,and feed it unclipped straight into the input of the scope,if I had just kept it connected to the circuits,the signal clipping would have given me misleading results since the signal clipping would have reduced the signal level,what you see in the screenshot is the signal being clipped by the diodes,not what's actually coming out of the Function Generator,I know it's a bit confusing...
I think the actual signal levels aren't really that important,what is important is the clipping characteristics,as you see,the Ge diodes have a softer turn-on knee,I have found in practice that you actually need more signal level to get two back-to-back Ge diodes to clip because of the soft-knee turn-on characteristic,since it is a more gradual process...
See,because of the softer turn-on knee,it is harder to determine where the Diodes start clipping the signal,whereas with Si diodes,it's a different story,the signal remains unclipped before it gets to a certain level,then the Si diodes suddenly start conducting....
Yeah,I know it's a bit wierd...
Well,that's best way I can explain it anyway,I may be totally wrong about that though....
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.