Bedini Comparator Cap Dump

[Tom C]

your comparator should be dumping at 2x battery voltage set at the comparator dump potentiometer. pulse power is hard to see with a meter, the only way to really see it is with a scope and a current probe, hundred amp probe minimum.

Tom C

[adys15]

Your right Tom,2x bat voltage.but i was refering at dump voltage 15v and 15v in at the coil i measured the amps with an analog meter like John had in the Energeticx video.Thanks

[Tom C]

with an analog meter you are just getting an average, the dump is much faster than a meter can react to. you are probably upwards of 40-60 amps right when the fet opens.

Tom C

[adys15]

Thanks,i put a bulb in place of the ammeter and it it lights like at 3A no drama

[AlvaroHN]

I am going to build the 12v RS_ comparator, and have a couple questions:

1 - On ebay, there are electronic parts, for example the irfp260 and the price is like 10 for US$ 15.

is that the normal price? or those are pirate parts or something?

2 - if I would like to add a dump indicator led, I could add a led in series with the h11d1 isn't? (led side of the h11d1)

best,

Alvaro

[Tom C]

I have never seen fets that cheap unless he is buying them in hi bulk and passing on the savings. if you buy them at 100 price quantity you can get them for 1.38 each from mouser. ask them if they are Fairchild or on semi, what is the brand.

http://www.mouser.com/_/?Keyword=IFRP+260+mosfet&FS=True

I can get some to you also, I have them here. send me an email.
Tom C

[AlvaroHN]

I have never seen fets that cheap unless he is buying them in hi bulk and passing on the savings. if you buy them at 100 price quantity you can get them for 1.38 each from mouser. ask them if they are Fairchild or on semi, what is the brand.

http://www.mouser.com/_/?Keyword=IFRP+260+mosfet&FS=True

I can get some to you also, I have them here. send me an email.
Tom C

ok Tom I just sent you an email

[Volty]

Hi alfinip2000,

In my case 100uF did it. We have been discussing that since post #68. If your circuit shows the same symptom first be sure that you are using the correct devices, check if the transistors are getting the correct triggering voltages.

P.S. That cap is not a panacea.

Lman

Hey,

Long time no reads. In this whole thread no one has set up a rotory selector switch for the Hysteresis Cap. I found that to control dumps per second rate, BOTH Cap Charging Bank and Hysteresis Cap must be selectable.

My box has one 4,700uF 50V always connected, which will be dumped, and i have gang switches to add another 4,700uF, than a 10,000uF, and another 10,000uF, for 29,400uF TL. Smaller bank dumps faster.

Selecting a smaller Hysteresis Capacitor also dumps faster and shallower. Adjusting Dump Threshold Voltage back up where it was helps, but the ability to change combinations of capacitors is the very best you can attain i say.



*EDIT - Note that the Dump LED in Mirrored trace Layout is backwards.

[Nityesh Schnaderbeck]

Some Suggestions


Hey there, I admire your efforts on this circuit. I have some suggestions for you, please don't take this the wrong way.

For a start get rid of that opto-coupler(H11D1) and Q1(BD243C), they are not needed in this circuit, and drive the fets/mosfets directly from the op-amp. The opto-coupler(H11D1) and Q1(BD243C) circuit is seriously compromising the sharp switching of your fets/mosfets. Drive the fets/mosfets with 100ohm or 220ohm matched resistors, from the op-amp. Driving the fets/mosfets using an op-amp(741) eliminates the need for R3(10K) and R4(10k). The gates of the fets/mosfets have a parasitic capacitance, so you want to charge this parasitic capacitance quickly by using low resistance driving resistors for a sharp turn on. Also you want to discharge this parasitic capacitance quickly, the op-amp/comparator shorts the mosfet drive to ground when turned off, discharging this parasitic capacitance quickly, so you get a very sharp turn off.

Using a op-amp/comparator alone only maintains the Capture capacitor(C1) at the set voltage. You also need a hysteresis triggering system like a "schmitt trigger" or something. So you can charge the Capture capacitor(C1) to a set voltage and discharge to a set voltage. A "schmitt trigger" can be designed with adjustable hysteresis, to fine tune your cap dump charging system.

"Volty" Your rotary switch is good for, finding the right capture capacitance, but the switch contacts will add, unwanted impedance's, and compromise the charging and discharging capability's of the capture capacitor. If you are only using an op-amp/comparator, changing the value of the capture cap, will not add much hysteresis, if any to the circuit.

I hope this helps.

You can also look at this thread, http://www.energyscienceforum.com/showthread.php?t=2020

[RS_]

Hi,

This Schematic SNAGs-002, is My 12V version of John Bedini's, 36V Comparator Cap Pulser Schematic, presented at the 2011 conference.....
So I will not go into why he did it this way.......

But your schmitt trigger pulser should do the same job......
the mosfets gates can also be driven by standard Mosfet driver chip's and the 741 op amp or schmitt trigger, triggering the driver inputs........... most of the dedicated Mosfet drivers have something like a schmitt trigger integrated into their input circuitry anyway........

lots of ways to skin this cat..........

[RS_]

Volty,

Very pretty work on your cap pulser circuit, and the mounting up in the box.......

making it adjustable like this, lets you change batterys sizes easy, or adapt to different input sources easy

Good work.....

[Nityesh Schnaderbeck]

One of the best solid state switches I have ever made was with a LM358 op-amp(as a comparator) driving a mosfet. The mosfet pulled power though a coil, and the back emf was directed through a diode, (like in the original ssg circuit, but with a mosfet instead of a transistor.) I has a neon connected across the mosfet(IRF840). Out out all the solid state switches I made, the op-amp driving the mosfet gave the best purple flash in the neon. Indicating a good radiant voltage spike. Even John Bedini mentioned, that a Comparator driving Fets was the best switch, in his "Linear Amp Regulator" DVD. I had lots of trouble making mosfets switch clean in the early days, until I discovered the comparator driving the mosfets, after designing many circuit configurations and staying up all night.

As simple as the configuration is, of the LM358 op-amp as a comparator driving a mosfet. It took me years to figure this one out.

[Lman]

Hey,

Long time no reads. In this whole thread no one has set up a rotory selector switch for the Hysteresis Cap. I found that to control dumps per second rate, BOTH Cap Charging Bank and Hysteresis Cap must be selectable.

My box has one 4,700uF 50V always connected, which will be dumped, and i have gang switches to add another 4,700uF, than a 10,000uF, and another 10,000uF, for 29,400uF TL. Smaller bank dumps faster.

Selecting a smaller Hysteresis Capacitor also dumps faster and shallower. Adjusting Dump Threshold Voltage back up where it was helps, but the ability to change combinations of capacitors is the very best you can attain i say.

[ATTACH=CONFIG]4075[/ATTACH][ATTACH=CONFIG]4076[/ATTACH]

*EDIT - Note that the Dump LED in Mirrored trace Layout is backwards.

Hi Volty,

Nice work !
I had the same idea of switching different cap sizes for different smaller battery sizes but at the end I never did it so ... thumbs UP !! ;-)

Long ago I was experimenting with a small 9V rechargeable NiMH that was dead. I did not know how much of a dump would be suitable for it and I was afraid it could explode. So I started with a 2200 uF cap and than added one more in parallel, than one more up to 4 together.
This is when it downed on me that I could use some kind of switching for different batteries.

I want to share the problem I experienced back than playing with this. Three of the caps I had were the same and the forth one was different brand and taller (lower ESR). Using only the taller one alone the circuit behaved nicely. As soon as I put one of the others though it started to dump faster and shallower. I did not like that and than I started adjusting the "hysteresis" cap as you call it or C2 cap in case you use RS_'s circuit. So I concluded that caps with the same Low ESR should be used.

Regards
Lman

[Nityesh Schnaderbeck]

"Volty" nice PCB layout artwork, remember to thicken the tracks coming from the cap with solder, silver solder is best.



If you are using this circuit above, here is a small enhancement mod. Connect a 100Kohm stabilization resistor between pin4 and pin6 of "opto 1"(H11D1) this will improve the switching, and help prevent false triggering. Pin6 of the "H11D1" is sensitive to picking up noise with no stabilization resister especially when multiplied by the gain of "Q1"(BD243C).

you can also try connecting the 100Kohm stabilization resister from "pin6 of opto 1" to the emitter of Q1(BD233C), since the photo transistor inside "opto 1"(H11D1) and "Q1"(BD243C) is connected as a darlinton.

But find out what works best. Just helping you out.

[Ren]

Hi Nityesh,

Would you care to share the comparator driven mosfet circuit by any chance?

Regards