Energy Movement
Laws of Physics
Signals and energy move in the spaces, not in the traces.
When a principle of physics is accepted, it explains phenomena everywhere in the universe. The law of gravity works on matter, whether the masses are located on earth, in the sun and or among the stars. The law must transition at the atomic level where the particles must follow the laws of quantum physics. There may also be a transition when dimensions are those of the entire universe. For the world, we can sense there is only one law.

The laws I want to talk about are the basic laws of electricity. I am not referring to circuit theory laws as described by Kirchhoff or Ohm, but to the laws governing the electric and magnetic fields. These fields are fundamental to all electrical activity, whether the phenomenon is lightning, ESD, radar, antennas, sunlight, power generation, analog or digital circuitry. These laws are often called Maxwell’s equations.

The energy we get from sunlight travels in space. The energy comes to us as electromagnetic waves. This means there are both electric and magnetic fields present in the light. There are no wires. This field energy is moving at the speed of light.

close view of circuit board schematics
Figure 1. Circuit board schematics suggest energy moves through conductors. The laws of physics say otherwise.
Visible light is electromagnetic field energy where the wavelength is 10-7 meters. Radar is electromagnetic wave energy where the wavelength is 10-2 meters. Utility power is electromagnetic wave energy where the wavelength is near 10 million meters. Lenses can direct light energy; waveguides can direct radar energy; and copper conductors can direct the energy at power frequencies. Thus, we direct energy flow at different frequencies by using different materials. We have learned how to control where we want the field energy to go.

If we accept the idea that fields carry energy in space, it must be true at all frequencies. That is the law. If it is true for light, it must also be true for 60Hz power and at DC. For utility power, the energy travels in the space between conductors, not in the conductors. This is not the picture presented by circuit diagrams, where energy seems to be carried by conductors. In digital circuits, the signals and energy travel in the spaces between traces or between traces and conducting surfaces.

Buildings have halls and walls. People move in the halls, not the walls. Circuits have traces and spaces. Signals and energy move in the spaces, not in the traces.

Ralph Morrison spent more than 50 years in electronics engineering and authored eight books, including Solving Interference Problems in Electronics, Grounding and Shielding Techniques in Instrumentation, and The Fields of Electronics: Understanding Electronics Using Basic Physics. He passed away in December 2019. He authored this essay in 2010, and it was provided to PCD&F by his protégé Dan Beeker.