I hope you can help me. I have a project with operational amplifiers. In this project I need to create a mirror signal (symmetrical signal) from this output:

output signal

To something like this:

symmetrical signal

The two requirements are:

  • Only use operational amplifiers, resistances and capacitors
  • The circuit must have two inputs, a square signal and a triangular signal

I've tried with many settings, but I have not succeeded.

I created this circuit with the original output, but I don't know how can I get the mirror of a symmetrical signal:

circuit created

If someone can help me I will appreciate it.

  • \$\begingroup\$ Are you looking for en.wikipedia.org/wiki/Operational_amplifier#Inverting_amplifier to do the "mirroring"? \$\endgroup\$ Commented Jul 13, 2021 at 4:33
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    \$\begingroup\$ The simplest way is the standard inverting amplifier with G=-1… just use equal feedback resistors. By the way 20nF on the feedback of your first amp are a lot, do you need some heavy filtering? \$\endgroup\$ Commented Jul 13, 2021 at 6:13
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    \$\begingroup\$ For first signal, just add the 2 generators ... For the second, just substract. Amplitude of square bigger than triangle. Use a more clear schematic. It help. :) Some resistance are "too lower". Use 10k, for example. Under 15 V there is a current of 1.5 mA max. If using 500 Ohm, it can be ...30 mA ! On board, add always decoupling capacitors nearest opamp. \$\endgroup\$
    – Antonio51
    Commented Jul 13, 2021 at 8:07
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    \$\begingroup\$ Thanks to everyone. I could solve the problem this is the solutions. Thanks @FlorianRagwitz, LorenzoMarcantonio and Antonio51 \$\endgroup\$
    – bisonte
    Commented Jul 13, 2021 at 18:17
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    \$\begingroup\$ @bisonte Would you like to post an answer to your own question to help out other people with a similar problem searching the site in the future? \$\endgroup\$ Commented Jul 13, 2021 at 19:24

1 Answer 1


I could solve the problem this is the solutions:

symmetri signal

  • 1
    \$\begingroup\$ @DavideAndrea - Hi, Please look at the comments below the question. This is the OP's self-answer, no matter whether it's right or wrong. If the OP thinks it is the answer to their question, then it is an answer. (As usual, people can vote and/or comment about its correctness.) Also answers (including self-answers) should not be added into question, so it's the wrong advice to ask an OP to add their solution into the question. This is why self-answers exist, so that OPs can write their solution as an answer. || If you have questions on this etiquette, please ask on our Electrical Engineering Meta. Thanks. \$\endgroup\$
    – SamGibson
    Commented Oct 7, 2023 at 15:45

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