Let's say if company A developed an electronic product. A published the product's datasheet on its website free to the public, copyright of the datasheet is owned by A. One part of the datasheet is the schematics of the product.

Is it fair use, if company B develop a digital simulation model (a software program) and make it free to public, that does not contain A's original schematic, but contains rewriting of the schematic into a digital form?

  • 1
    Why would it be fair use?
    – phoog
    Commented Nov 28, 2023 at 7:20
  • "Rewriting" is just a fancy term for "derivative work"... look that up.
    – Trish
    Commented Nov 28, 2023 at 7:27

1 Answer 1


Copyright does not apply.

From the description, company B is simply copying the circuit design. Copyright would only protect that specific schematic drawing of the circuit. The design of the circuit, i.e. how chips and resistors are logically connected, is utilitarian and is not protected by copyright.

Instead, patents may apply. If the original datasheet wasn't public, then trade secret laws may also apply. Trademarks may also apply to product names, so they will have to be used carefully.

  • I don't see that a bare simulation could infringe a patent. In theory if someone puts the simulation on e.g. a Raspberry Pi and uses it in place of the original circuit then it might, but even then the liability would be on the person with the RPi rather than the simulation author (unless the simulation author explicitly encouraged that use of course). Commented Nov 28, 2023 at 12:03
  • @PaulJohnson Take for example a circuit that implements a patented cassette tape noise reduction system. A simulation, i.e. software implementation, could still infringe on claims that are written as signal processing blocks and filters and not just connections of transistors and diodes.
    – user71659
    Commented Nov 28, 2023 at 18:12
  • I understand the design of the circuit is utilitarian and not copyrightable, so a drawing by analyzing the physical circuit product does not infringe the schematic's copyright, but can a simulation model created partially by reading the schematic and writing it in digital form (list of components and electric connections) be considered "derivative work" of the schematic?
    – Ligon Liu
    Commented Nov 28, 2023 at 20:20
  • @LigonLiu A derivative work refers to copyright laws. If the data isn't copyrightable, then it doesn't mean anything.
    – user71659
    Commented Nov 28, 2023 at 20:50

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