[2538] Changing Diode Vf

Date: March 15th, 2019 | Comments : [1] | Categories: DIY.

The forward voltage of a diode is not fixed, and this is easily seen on the datasheet for the 1N4148, for example. At 200ma, the 1N4148 diode Vf is over 1v but if the current is only 1ma then the Vf is less than 0.625v. As the current goes lower, so does the diode’s Vf.

This circuit will vary the peak clipping of the diodes, but only over a modest range. Also, the opamp driving it must be capable of sourcing enough current to make a difference, and you have to be careful that the power rating of the 47 ohm resistor is not exceeded.

The circuit is of limited practical use, but there it is for your experimentation anyway!


One Response to “Changing Diode Vf”

[786303] admin Says: 10:00 am, March 18th, 2019

If I were going to try this, I would use an NJM4556AD opamp to get started. Another possible choice would be an LM386.


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