Hi all!

I'm an EE and was intriqued by MEG because of simple circuitry
required to operate. I've built my own replication of the MEG - also
unsuccessfully (I mean I didn't obtain COP > 1). In my controller I
can independently change both frequency and duty cycle of the gate
driving voltage. My MEG has taps on both primary and secondary
windings and I can play with turns ratio. While working without load,
I obtained output voltage with close to sine waveform and amplitudes
around reported by Bearden and Naudin. However, after loading the
output (even lightly with 100kOhm resistor), output voltage decreases
significantly to a few volts.

It's pretty hard to debug the device since I don't understand how it
should work. I started to dig into Berden's patent and I have a
question: does anybody have an idea how Bearden measured the current
in both primary (Fig 6D) and secondary (Figs 6G,H)?

The question arised because the primary current he described has
extremely small duty cycle - around 1 microsecond for both rise and
fall. It supposes duty cycle with around 500 nanoseconds of active
driving voltage - nothing comparable can be seen in Figs 6A,B. Also I
tried to build high side current measurement circuit and (even with
most recent chips!) it has around 500kHz bandwidth and cannot provide
such a sharp waveform. Thus I presume that Tom measured a voltage on
a small low side resistor. The voltage produced by such measurement
can have short spikes as presented in Fig 6D because of capacitive
coupling from adjacent circuitry and even from the ground ripple
itself.