This Circuit Board Can Rewire Itself – EEJournal

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May 28, 2026

This Circuit Board Can Rewire Itself

by Max Maxfield

I want you to close your eyes and imagine something. I’ll tell you when you can open them again. Hmmm, that won’t work, will it? OK, let’s try something different. Imagine you’ve closed your eyes and you are visualizing a printed circuit board (PCB) from the future, except the ‘P’ is a misnomer because this board is not “printed” per se.

Let’s come at this from a different direction. Do you remember the 1991 movie, Terminator 2: Judgment Day? One of its stars is an advanced, shape-shifting Terminator—a model T-1000, no less—that’s made of virtually indestructible liquid metal. I’m thinking about the scene where the T-1000 simply oozes through the steel bars blocking a corridor in the prison where Sarah Connor is being held. I still have goosebumps.

Well, keeping the T-1000 in mind, imagine a circuit board whose liquid-metal tracks and vias can be reconfigured on demand. “This is all very Buck Rogers in the 25th Century,” I hear you say, “but what does it have to do with the here and now?” I’m so glad you asked, or else I would have been obliged to think of some cunning way to bring what I’m about to tell you into the conversation.

In a crunchy nutshell, a company called Itera has just emerged from deep stealth mode to announce a new circuit board technology whose liquid-metal tracks and vias can be… you’ve guessed it… reconfigured on the fly before your very eyes.

In case you were wondering, Itera takes its name from Iterate, which is particularly pertinent because we tend to do a lot of that during the prototyping phase of a new project.

Speaking of prototyping, I’ve certainly served my time. Considering only professional activities, I started in the early 1980s with hand-soldering wires onto rudimentary prototype boards carrying naught but plated-through holes and pads. Later, the company I worked for adopted a technique called “wire wrap,” which was originally invented to wire telephone crossbar switches and later adapted for constructing electronic circuit boards. Robert Jenkins has a great video of this on his technology channel.

Later still, we acquired (or rented, I’m not sure which) a monstrous Multiwire machine. In this case, the board’s surface was covered with a layer of adhesive wiring film. A special computer-controlled wiring machine was used to ultrasonically bond extremely fine wires into the wiring film. These wires had an insulating polyimide coating and could be wired orthogonally (north-south, east-west), diagonally, or in combination. Since the wires were insulated, they could cross without forming unwanted connections.

I remember a crowd of us setting this machine running in the evening before heading home. When we reconvened in the morning, our new Multiwire prototype board was ready for us to populate with components to find out what we’d done wrong on our design. Although this may sound like a lot of effort, it was better than waiting two or three weeks for a prototype PCB to arrive from the local board house.

One more thing before we proceed: the folks who create circuit boards enthusiastically mix and match units as though it were a competitive sport. For example, it’s common to specify track widths and spacings in units of "mils," where one mil equals 1/1000th of an inch. The term derives from the Latin mille, meaning "thousand," which explains why generations of engineers and machinists have colloquially referred to it as a "thou."

Because modern electronic components (excluding legacy through-hole devices) have mostly transitioned to metric pin spacing, it is extremely useful to know standard conversions, such as 1 mil = 0.001 inches and 1 mm = approximately 39.37 mils. Just for giggles and grins, some people talk in microns (millionths of an inch). For the purposes of this column, it’s worth knowing that 100 microns is approximately 4 mils.

Last but not least, standard low-cost PCBs typically have 6-mil line-and-space (trace width and spacing) rules; mid-range boards are usually in the 4–5-mil range; and advanced boards push down into the 2–3-mil realm.

I just had a very interesting, if not mind-boggling, chat with AJ Cooper, who is CEO and Co-founder of Itera. At first glance, Itera’s technology looks like something that escaped from a science-fiction movie. The company’s prototype board isn’t built from FR4 fiberglass and copper traces. Instead, it’s formed from multiple layers of ultra-thin glass containing microscopic channels through which liquid metal can be directed to create traces and vias on demand. The entire structure is sealed, so the liquid metal is never exposed to the outside world. Take a look at this visualization of Itera’s fluid circuit board technology in action.

One way to visualize this is to imagine a circuit...