Nothing Is Something: The Theory and Operation of a Phase-Conjugated Vacuum Triode

Floyd Sweet on Bearden's web site

Floyd Sweet
"There is suppression launched against any free-energy inventor who
succeeds or is very close to succeeding." - Ret. Lt. Col. Thomas Bearden

...For decades, new-energy researchers talked about the possibility of
treating a magnet so that its magnetic field would continuously shake
or vibrate. On rare occasions, Sweet saw this effect, called
self-oscillation, occur in electric transformers. He felt it could be
coaxed into doing something useful, such as producing energy. Sweet
thought that if he could find the precise way to shake or disturb a
magnet's force field, the field would continue to shake by itself...

~ Copied from NARKIVE
Floyd Sweet (1912–1995) was an electrical engineer and inventor with a background in magnetics and electrical systems. Later in his life, Sweet began exploring unconventional energy systems. His most notable invention, was the Vacuum Triode Amplifier (VTA).
The VTA required only a small input of electrical energy (milliamps) to generate substantial output power (up to several kilowatts). Reported coefficients of performance (COP) ranged from 10 to 1,500.
Sweet's device utilized specially conditioned permanent magnets that he claimed could resonate with the vacuum energy or zero-point field (The Aether).
The VTA reportedly became cooler as it operated, suggesting that energy was being drawn from an external source rather than conventional thermodynamic processes.
The device was static, relying on electromagnetic fields and magnetodynamics rather than mechanical motion.
The output energy was described as having a low frequency, often likened to 60 Hz AC power, which could directly power standard electrical appliances.
Sweet claimed to use rare-earth magnets that underwent a proprietary "conditioning" process to align their atomic structure in a way that allowed them to tap into vacuum energy.
By achieving a resonance between the magnets and the electromagnetic environment, the device could purportedly draw energy from the vacuum field.
The device utilized a feedback mechanism to maintain resonance and stability.
One interesting note on it's operation over extended periods of time, was a change in it's output. Sweet believe, the variations came from the Earth's movement though space. This is remnant of how scientists measure gravitational waves.
Floyd Sweet's work is sometimes grouped with other controversial inventors like Nikola Tesla and Thomas Townsend Brown, whose ideas challenged conventional paradigms.