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Diode Clipper variable between two clipping levels

Started by Vivek, October 06, 2020, 10:41:33 AM

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Vivek

October 06, 2020, 10:41:33 AM Last Edit: October 07, 2020, 01:35:38 AM by Vivek
Elmers like Craig, TeemuK, RG, AMZ etc have studied all possible diode combinations 20 years ago.  Respects !!!!!

I just input one of their well known variants into SPICE.









LEDs clip at 2.5V. The other diodes clip at 0.6

The pot R2 allows continuous different combinations between

Hard clip at 0.6V
different types of soft clip starting from 0.6V
Soft clip at 0.6 but part is further limited at 2.5V
Hard clip at 2.5V

Vivek

#1
October 06, 2020, 11:08:17 AM Last Edit: October 06, 2020, 11:42:55 AM by Vivek
It's also possible to make the clipping asymmetrical and have the degree of asymmetry to be continuously variable

antonis

#2
October 06, 2020, 02:20:11 PM
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Vivek

#4
October 06, 2020, 11:03:23 PM
Quote from: antonis on October 06, 2020, 02:20:11 PM
https://www.diystompboxes.com/smfforum/index.php?topic=125518.40

reply #51


LEDs clip at 2.5V. The other diodes clip at 0.6

The pot R2 allows continuous different combinations between

A. Hard clip at 0.6V
B. different types of soft clip starting from 0.6V
C. Soft clip at 0.6 but part is further limited at 2.5V
D. Hard clip at 2.5V

If we don't have the second set of diodes with higher Vf, we don't get options C and D

antonis

#5
October 07, 2020, 04:47:14 AM
Quote from: Vivek on October 06, 2020, 11:03:23 PM
C. Soft clip at 0.6 but part is further limited at 2.5V
D. Hard clip at 2.5V
If we don't have the second set of diodes with higher Vf, we don't get options C and D

C. No.. Clipping threshold is definite and is determined by total voltage drop..
D. Can be obtained for a 1.9V voltage drop across pot..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Vivek

#6
October 07, 2020, 07:41:16 AM
I think the reason why to have second set of higher Vf diodes which places second clipping limits to the signal will be easy to see if I post SPICE outputs with no second set of higher Vf diodes.




Please compare this graph with the earlier one that had the LEDS in situ as well.

Vivek

#7
October 07, 2020, 07:56:28 AM



The second set of diodes impose a limit to maximum signal output, and distort the wave

Net result is a soft clip at 0.6V and a hard clip at 2.5Volts.

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