By Michael Barr
Note: This article offers practical guidance for attorneys engaging technical experts. It is general commentary, not legal advice. Consult counsel about any specific matter.
An electronics expert witness reads schematics, board layouts, and chip designs the way a software expert reads code, and turns what they find into opinions a court can use. Barr Group is an expert witness firm that connects those engineers to attorneys at no cost, with an hourly fee if retained, and the criteria below are what we test a candidate against before we put a name in front of you.
Electronics cases have a particular failure mode. The accused thing is a physical object, the evidence is usually a description of that object, and the two are not the same. Almost everything that goes wrong in these matters traces back to an expert who forgot which one they were looking at.
They match the layer, not the word "electronics"
A claim can read on a circuit topology, a board layout, the logic inside a programmable part, the firmware running on it, or the physical arrangement of a fabricated die. Those are five different disciplines and largely five different people.
The failure mode is retaining a capable engineer whose experience sits one layer away from where the claim reads. They will produce competent analysis of the wrong thing, and it will not be obvious until the opposing report arrives. Ask a candidate which layer they have personally worked at, and get a specific answer.
They can distinguish the design from the product that shipped
A schematic is intent. A netlist is a compilation of that intent. A fabricated part is what was sold, and it may differ from all of the above, because features get disabled by fuse settings, populated differently across board revisions, or changed late in manufacturing.
An expert who treats the design database as the accused product has an obvious hole in their opinion. The strong witness establishes early what has been produced, what it describes, and what would be needed to connect it to the physical unit.
They test, and they say what testing showed
Electronics is measurable. Bench testing, oscilloscope and logic analyzer captures, thermal imaging, power measurement, and where it is warranted, decapsulation and die imaging, all produce evidence about the accused article rather than about its documentation.
The counterpart discipline is honesty about limits. Simulation shows what the model does under the stimulus chosen, and an expert who lets that stand in for the behavior of the shipped part will be cross-examined on exactly that difference.
They read hardware description languages as hardware
Verilog and VHDL look like source code and are not. They describe logic that operates concurrently across clock edges rather than statements that run in order. A reviewer who reads an always block the way they would read a C function will describe the design incorrectly and do it with confidence.
If a case touches programmable logic, the reviewer needs to think in registers, clock domains, synthesis, and timing closure. That is a working hardware engineer, not a software engineer who has seen Verilog.
They understand what the firmware is doing to the hardware
Many claims that look like hardware claims are practiced partly in code that ships inside the part. A timer peripheral configured by one line of C, a power state machine in firmware, a calibration table in flash. Splitting hardware from software cleanly is usually impossible, and an expert who insists on the boundary will miss the mechanism.
This is the most common reason an electronics matter needs two experts working under one methodology rather than one stretched across both.
They know where third-party blocks change the question
A large share of any modern design is licensed from outside: a processor core, a memory controller, a standard interface block, a reference design the vendor supplied. When the accused functionality lives inside licensed content, questions about who practices the claim and what the license already covers arrive before any technical analysis matters.
Discovering that at deposition is avoidable. Early technical scoping is what avoids it.
They can teach a circuit to a jury
Jurors have no mental model for any of this. The witness has to build one in minutes, using an analogy that survives cross-examination, and then connect it to a claim limitation. That skill is uncorrelated with credentials and it decides how much of the analysis actually lands.
Where this has mattered for us
After years of attack and counterattack between pirates and DirecTV, the broadcaster filed tens of thousands of federal lawsuits over interception of its programming. A team of Barr Group electronics experts reverse engineered more than a hundred devices sold over the internet for that purpose and concluded, across more than 6,000 pages of expert reports, that nearly all of them were primarily designed for theft of service. Several dozen of those matters went to trial and Barr Group experts testified in more than twenty jury trials and hearings.
That work rested on physical devices and their firmware rather than on documents, which is the distinction this whole page is about. The full case study sets out the method, and our article on semiconductor and chip-design disputes goes deeper on the layer question for chip cases specifically.
Expert profiles in this field
Anonymized profiles of electronics experts. Names follow a conflicts check.
- Electronic vehicle controls
- Semiconductor process integration
- Semiconductor manufacturing and process control
- Thermal management and electronics cooling
- Printed electronics
- Manufacturing automated test
- Power electronics and motor drive
How we help
We match reviewers to layers rather than assigning a generalist, and we say plainly when a matter needs a circuit engineer and a firmware engineer rather than one person covering both thinly. Our electronics expert witnesses and embedded systems expert witnesses work under protective order routinely, and where no documentation exists our reverse engineering practice works from the physical article inward.
The search is free and confidential for the attorney. Our fee is built into the expert's hourly rate, so we are paid only if you retain. Tell us about your case.