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I have been studying electronics a bit at home in my spair time. I was wondering if manufacturers make schematics for PCBs? If I could get ahold of something like that i feel that I could understand the flow of the board better.

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    \$\begingroup\$ No, they don't, because they'd be giving away their design. Learn how to reverse engineer \$\endgroup\$ – Voltage Spike Feb 7 '18 at 16:56
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    \$\begingroup\$ You pretty much need to make a schematic first, then make a PCB to implement it physically. So, yes. (But you're only likely to find a manufacturer's schematics if they offer a service manual). \$\endgroup\$ – Brian Drummond Feb 7 '18 at 16:56
  • \$\begingroup\$ The "source files" for PCB manufacturing are mostly given as "Gerber files". \$\endgroup\$ – Eugene Sh. Feb 7 '18 at 16:56
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    \$\begingroup\$ some manufacturers do ... check out arduino.cc \$\endgroup\$ – jsotola Feb 7 '18 at 16:58
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    \$\begingroup\$ As other answers note, getting a schematic for a particular device, particularly a modern one, is not often feasible, but many older pieces of electronics have service manuals containing both PCB and schematic diagrams, and those manuals make their way onto the internet. Vintage analog synthesizer service manuals have been educational for me. \$\endgroup\$ – Russell Borogove Feb 7 '18 at 17:46
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Yes, all PCBS have schematics. The ones that are public include

  • Open Source Hardware

  • Very simple designs are often based around an example schematic provided in the data sheet of the primary IC. You can usually obtain the data sheet from the IC manufacturer.

Bus Pirate schematic Bus Pirate

enter image description here enter image description here

AD603 Data sheet

However, as other answers point out, the majority of schematics for PCBs in commercial products will not be available to the public.

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    \$\begingroup\$ Along these lines another nice application board that you can read up on and probe with a meter is the Gertboard I/O board for the Raspberry Pi. This is nice because there's some discussion of the rationale behind some of the design decisions, as well as schematics \$\endgroup\$ – Chris H Feb 7 '18 at 20:28
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I'd say most of the PCBs do have a schematic somewhere, and it would greatly improve the understanding of the PCB and the functions of all the parts if it was available. Especially giving all the intended sizes and ratings of the small parts (resistors, capacitors).

But it contains the essence of the circuit and quite often many years of experience designing circuits. Most of the time, people don't want to disclose all that information to the public, especially in a commercial product.

The layout is another important part however - with multilayer PCBs it is also a bit of a hassle to reproduce that.

It was more common in the earlier days where a technician would actually repair the device instead of sending it back to the factory. These service instructions sometimes contained a complete schematic, but sometimes only parts which were supposed to be serviced.

Nowadays, some companies propagate Open Hardware, which is basically open source hardware, but there a problem arises as not all formats which are widely used are accessible for a wide variety of people. What is the worth of a schematic published in Altium or Mentor file formats, which cost several thousand dollars (okay some come with a Viewer, but you cannot modify it).

And thinking about the projects I'm involved in - a schematic wouldn't help you one bit. It basically consists of a MCU and an ASIC - both of which you will not know what they are doing. The MCU contains some software (which you could get and try to reverse engineer) and the ASIC is doing something which you would have to analyze with a black box approach, also quite difficult.

So even with the schematic you might not get much further in understanding a circuit.

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Pretty much all PCB's are based on some form of schematic, even if it was just drawn on the back of a napkin.

Most manufacturers do not publish their schematics as they are proprietary designs. There are a few exceptions to this, and some will release schematics to approved field repair facilities.

If you know the manufacturer, and they have support documents on-line you can check their website for a schematic. You can also try contacting them, but do not be surprised if they tell you no.

In many cases having the manufacturers schematic will not help you much. In todays heavily digital and integrated systems most of the functionality is buried in the programmed parts. Many schematics you can't even tell what the thing does from the schematic other than perhaps a clue from the title block.

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  • \$\begingroup\$ Thank you everyone. I work with HVAC/R equipment and have to fallow machine schematics to find electrical problems but often they lead me back to some board. Beyond a few test points, you really dont know anything other than the board is bad. I was hoping fo a diagram to the board like i have for the high voltage side of the equipment. To beter understand the hidden control side and potentially be able to make temporary repair until new electronics come in. Thans again. \$\endgroup\$ – user173265 Feb 8 '18 at 0:00
  • \$\begingroup\$ I do tinker with breadboarding simple circuits for fun i guess but the nature of my question was more to hopefully find a flow chart or ladder diagram to a pcb. Something like the mechanical schematic that the equipment i work on comes with. \$\endgroup\$ – user173265 Feb 8 '18 at 0:07
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If you are interested in understanding the schematics of PCB, how to reverse engineering is what you are looking for.

I bought a cheap webcam that has built-in LED light, dismantled it, and ran a wire from the webcam to the PC. The lens on what I have is adjustable, allowing me to reduce the focal length. The resulting setup is a great "macroscope" to see where the traces are running. I'd probably 3d print a case for this

this is as close as it can get without the camera's lens case casting a shadow.

EDIT: added one more picture as per pipe and Thomas Weller's advice
The traces are visible despite the bright light from the LEDs

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    \$\begingroup\$ The "seams" are called "traces." \$\endgroup\$ – JRE Feb 7 '18 at 17:30
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    \$\begingroup\$ @JRE My bad, this is my first answer, my anxiety took over the wheel at the end. \$\endgroup\$ – Big_Chungus Feb 7 '18 at 17:35
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    \$\begingroup\$ Your second picture disproves your point - I don't see any traces at all. \$\endgroup\$ – pipe Feb 8 '18 at 8:03
  • \$\begingroup\$ Please make those pictures smaller. Crop it to the minimum needed size. \$\endgroup\$ – Thomas Weller Feb 8 '18 at 14:09

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