Shorting coil gives back more power

[Feynman]

- 10ns class switching

lulz how about the DRF1200  pewpew


DRF1200 MOSFET/driver hybrid

The DRF1200 MOSFET driver hybrid. This hybrid includes a high power gate driver and
the power MOSFET. It was designed to provide the system designer increased flexibility
and lowered cost over a non-integrated solution

DRIVER FEATURES
• Switching Frequency: DC TO 30MHz
• Low Pulse Width Distortion
• Single Power Supply
• 3V CMOS Schmitt Trigger Input 1V
Hysteresis
• Drivers > 3nF

MOSFET FEATURES
• Switching Frequency: DC TO 30MHz
• Switching Speed 3-4ns
• BVds = 1kV
• Ids = 13A avg.
• Rds(on) ≤ 1 Ohm
• PD = 350W

http://www.microsemi.com/datasheets/DRF1200_A.pdf

only problem is its $$200  :*(

[Magluvin]

Hi Romero,

Fast or ultrafast type diodes are better at the frequencies you mention than the BY255 (which is a normal 50/60Hz type rectifier with t_rr=3usec reverse recovery time  http://maxdiode.com/Uploadpdf/BY250%20THRU%20BY255.pdf )
The reason you found better output when paralleling them is that their forward voltage drop get reduced, as Mario mentioned,  the reducement can be anything from say 60mV-80mV per diode, this is also nonlinear, in case of 5 paralleled diodes you may have got 0.7V loss instead of a single diode of say 1V.
At Farnell you may find the BY500-600 fast diode type (600V/5A, t_rr=200nsec price 0.191Ł one piece, order#1651065), this is much faster and has 1.35V loss at 5A (your BY255 has 1V loss at 3A) so at 3A this diode can be better if you also parallel 5 of them.

Best solution would be to use syncronous rectifiers: these are controlled MOSFET switches, see Fig. 3 in this link: http://www.national.com/vcm/national3/en_US/resources/power_designer/national_power_designer112.pdf

Will return to this later.

rgds,  Gyula

I had seen a setup that mosfets were configured to act like diodes. It was very simple, ill see if I can find.

Maybe they could be controlled with timing.  A solid state commutator.

Thats interesting that diodes in parallel can lower the voltage drop of diodes. Never heard that till now. Im surprised that parallel works at all. If we had an led with a limit resistor, it would light when V is applied. But 2 leds paralleled with 1 resistor in series, only one would light. All due to the fact that each led is slightly off tolerance from the next. The one with the lower V drop will be the one that turns on and the other not.  Maybe it is due to the resistor and rectifier diodes are different.

How many volts are we looking at here going through the diodes? If it is high, the dif between .7 and 1 volt drops should make very little difference. But if they do work in parallel, I would have to say that amperage capabilities would help keep the diodes cool, and maybe it is heat that causes the loss. I have had some hot rectifiers before, and maybe I should go back and try increasing the amperage with parallel diodes to see if I was missing something.

Mags

[giantkiller]

Getting way too complicated...
Small gauge wire, low current means smacking the coil very fast with high potential or a resonance pulse. SM and Willis showed very simple low component count.
Think Radio shack.
No egos, arguing or technical jargon. I am sure there are other high level ways to do this based on corporate or lab experience. But only a few of us have the simplicity on the benches that has shown the intense power of potential and not driving power. Intense potential is kinetic whereas intense power is current. Most of the experience in the these forums has been power trained and not potential trained. Sorry to step on toes here.

We are converting potential to power not the other way around.

With the correct coil setup 12vdc @ 300ma can cripple unshielded devices at a distance. Think about those physics instead of junction anomolies or device specifications.

The test I did many times in many configurations was to apply a stun gun circuit to the driver coil. The simplicity of this circuit can be made from Radio Shack. The parts come right off the rack including the little audio transformer.
Just add the Kunel patent configuration to this mix. Once again this makes and keeps it simple. SM mentioned 5khz audio frequency.

Special cores? Well the input parameters have to precise to match the core lattice makeup. This works but you are building a low grade nuclear rector in a specific operating range with a specific and precise inputs.

Otherwise this thread will go rocket science and drama like all the others.

SM talked about simplicity but was obscure. The Willis device shows simplicity. Hell, he didn't even try to hide it. He can't based on the Kunel patent.
He was so proud of what he had in the kitchen he was dancing around, jubilent in bare feet. He has a Canadian municipal contract. Good for him. A great way to get this out there is to use the government against itself. That is how giants fall...

[yssuraxu_697]

Feynman:

>Switching Speed 3-4ns

good

>BVds = 1kV

on the edge

> Rds(on) ≤ 1 Ohm

bad

***

BTW One of the the reasons NOT to have many turns / high resistance winding is when you DO interrupt the current in 10ns and for some reason fail to provide preset voltage load that can absorb all the energy in an instant (low resistance!) you will see all you stuff burn to hell like romerouk did.

What you DO need is many turns (in form of litz wire strands) / low resistance (in form of few windings) / high capacitance (in form of n-filar) winding. For example litz wire in n-filar configuration.

These are the very basics. No follow - no candy.

[Feynman]

> Rds(on) ≤ 1 Ohm

bad

Can you explain this to me why this is bad in more detail.  1 ohm is pretty low resistance, so you are talking fractions of an ohm being necessary?