I Built a Solid State Generator with a 500 Turn Coil (and Trifer Coil)

Hook

I fired up the solid state generator today using a coil 500 turns on top plus a big trifer coil on the bottom and watched it slowly charge the C-bank while the scope went crazy with 400-900 volt spikes.

Watch this experiment

We start with about 15 volts and half an amp going into the PWM. That drives a dual MOSFET timer which pulses the trifer coil and the upper winding. Output heads through a diode straight into the cap bank and we see roughly 28 volts across the load.

What you'll learn

You’ll see exactly how the trifer coil is wound, what frequencies I settled on, how the iron core gap affects things, and what the oscilloscope actually shows when this thing runs. All numbers come straight from the bench.

From the bench

Bottom coil is the trifer coil: 666 turns of 20 gauge plus a 22 gauge strand and either 30 or 32 gauge (I couldn’t get a clean reading on the exact gauge). Center has 11,000 turns of 32 gauge. Top coil is 1,500 turns of 20 gauge. Iron core runs through almost everything but leaves a slight gap so the two core halves don’t quite touch.

Input sits at 15 V and 0.5 A. Output into the C-bank reads about 28 V with the load connected. The little 4700 µF 63 V cap fills up fast; the big C-bank charges slowly because it has way more capacitance.

How it works / what we changed

Power goes to the PWM which sets frequency and duty cycle. The PWM triggers the dual MOSFET driver for a crisper pulse. At 83 Hz the blue LED blinks nicely and voltage climbs. I settled around 100–200 Hz after smelling a little transistor smoke. The scope shows a wild waveform—spikes jumping from 600 up into the 900s peak-to-peak, then settling to 400-600 when slowed down. The MOSFETs definitely clean the edges compared to raw PWM.

Trifer coil

The trifer coil sits on the bottom with three different wire sizes sharing one iron core. We start the generator cycle on the 22 gauge strand, hook it in series through the center winding, then send everything through a diode into the cap bank. The mixed gauges plus the core gap seem to create the slow but steady charge I’m seeing. It’s basically a big spool of leftover copper rolled onto a 3D-printed iron-infused PLA bobbin with the core poking halfway through the upper section.

Builder checklist

• Wind bottom trifer coil: 666 turns 20ga + 22ga trigger + 30/32ga strand
• Wind center: 11,000 turns 32ga
• Wind top: 1,500 turns 20ga
• Insert gapped iron core (do not let halves touch)
• Hook PWM to dual MOSFET driver
• Diode from 22ga output to cap bank positive
• Start at 100 Hz and watch for heat
• Monitor both small cap and large C-bank voltages

Troubleshooting

If you smell burning, back the frequency off—MOSFETs aren’t rated for everything I throw at them. Scope trace looks sporadic at first; slowing the timebase helps see the 400-600 V peaks clearly. If the C-bank charges too slowly, remember it has far more capacitance than the little 4700 µF cap so the rate looks different but may actually be similar.

Safety

These spikes hit hundreds of volts. Keep fingers off the output while running. Caps hold charge after power down—discharge them before touching. I bought extra MOSFETs because I expect some to let the smoke out.

FAQ

Why the gap in the iron core? It keeps the magnetic path from being fully closed; the transcript says the halves are “not really connected” except through fields.

Can I run this without the MOSFET driver? I think the pulses look better with it, but the video notes you could try raw PWM though results may vary.

What frequency works best? Around 100-200 Hz gave the nicest scope shots and rising voltage on the cap bank.

Is this free energy? No, we’re measuring 15 V at half an amp in and 28 V out under load—interesting but still follows normal rules.

Related on this site

• How to Wind Coils for a Pulse Motor (Step by Step)
• Best Wire Gauge for Pulse Motor Coils (AWG Guide)
• Pulse Motor vs Bedini Motor: What's the Difference?
• Reading Oscilloscope Output on a Pulse Motor
• Understanding Back EMF in Pulse Motors

Watch this experiment on YouTube

• ▶ Watch full on YouTube