Clipping diodes

[Jon Slaughter]

Sorry for all the posts but this will be the last one and then if I have any
more questions I'll wait and group them together.

I'm curious, again, as to if there is any way to make a diode's knee
smoother. I know that one can use an opamp to make an active diode but I'm
sorta interested in the opposite effect.

Thanks,
Jon

 

[John Popelish]

Sorry for all the posts but this will be the last one and then if I have any
more questions I'll wait and group them together.

I'm curious, again, as to if there is any way to make a diode's knee
smoother.

Add a resistor in series with it.

 

[Eeyore]

Add a resistor in series with it.

You beat me to it !

Graham

 

[John Popelish]

Sorry for all the posts but this will be the last one and then if I have any
more questions I'll wait and group them together.

I'm curious, again, as to if there is any way to make a diode's knee
smoother. I know that one can use an opamp to make an active diode but I'm
sorta interested in the opposite effect.

I might also add that in the "clipper" schematic you linked
to, the diodes cannot clip to zero incremental gain, because
they are connected in the feedback path of a non inverting
opamp configuration. The gain in that configuration is 1 +
the feedback ratio, so even if the diodes go to zero dynamic
resistance, the opamp continues to have a gain of 1 for the
input signal.

 

[Jon Slaughter]

I might also add that in the "clipper" schematic you linked to, the diodes
cannot clip to zero incremental gain, because they are connected in the
feedback path of a non inverting opamp configuration. The gain in that
configuration is 1 + the feedback ratio, so even if the diodes go to zero
dynamic resistance, the opamp continues to have a gain of 1 for the input
signal.

I think that is the point though? You don't want them to clip all the time.
As you turn up the gain they will clip more(and more of the highs than
lows).

Also, if there they could clip all the time then you would have no signal?


Thanks,
Jon

 

[John Popelish]

I think that is the point though? You don't want them to clip all the time.

I agree that the effect I described is another way to soften
the clipping effect of the diodes. If the opamp with the
diode feedback were connected as an inverting stage, the
clipping would be harsher.