# Search for perpetual in Topics

### Perpetual Motion? Answered

Can perpetual motion be achieved in space?

### Perpetual Motion

If perpetual motion is theoretically impossible, how is the earth still in orbit? Or how is anything in orbit? There falling at the rate at which the object there falling towards is rotating and they'll never stop rotating or falling so isn't that perpetual motion?

Topic by emuman4evr    |  last reply

### perpetual energy

I conceived an idea during my physics class in 1997 that having a perpetual energy is possible. i am currently working on it with the little funds i have which will take some time to complete and try it

Topic by cleanenergy bostile    |  last reply

### Proof of Perpetual motion? Answered

I am sorry I can't embed the video but you can find it on Youtube here  proof? :-)

Question by rickharris    |  last reply

### I know there is no such thing as perpetual motion? Why is that? Answered

Okay, no such thing as perpetual motion. Why is that? What about something that will run for a year before it has to be started up again. I guess what Im saying is people just slam perpetual motion and ignore it. But, what if? What if you only have to start it again once a year, a month, a week or even once a day. Don't you think we should look into this result?

Question by BluTiger    |  last reply

### Perpetual motion & free energy is it possible? Answered

Hi Eric/Instructables, Basically I have been looking at perpetual motion and am led to believe that it is impossible due to the laws of thermodynamics meaning heat/energy has to be transferred somewhere, so I came up with a few designs which may challenge this theory.  Without wanting to reveal my designs and ideas too much I will explain what I am trying to accomplish and would love your opinion as to whether you think they are viable. I have 2 ideas, one is to use 'rare' magnets (which aren't rare at all so cost and obtaining them is not as hard as it sounds!) and have the magnets propelling round like a wind turbine design using the opposite poles effect to repel the magnets and get the turbine started.  Once the turbine is in motion I will harness the electricity created by the movement of the turbine/motor in a capacitor or kinetic store. This stored  electricity  can be used to keep the magnets magnetized by wrapping wire coils round the magnets and passing the stored current through the coil to keep the magnets repelling each other and spinning the turbine. Idea number 2 is a similar concept just dropping the use of magnets and using the method of so called free energy where you can get a small voltage from using a radio antenna, capacitors and germanium diodes (there are several example videos on the internet) again using a wind turbine effect to keep re-fueling the capacitors so the voltage drop when the load is applied is nulified. Perpetual motion is the dream and I think the transfer of heat/energy caused by friction can be harnessed and put back into the workings of the appliance/design, Many thanks for your time in reading this and hope for any replies positive or negative the dream will live on in my head and heart  :)  Mark Smith

Question by McJesus    |  last reply

### mount a starter and alternator on plywood with a belt attached to each,...would that be perpetual motion ?

Question by 19751968firebird    |  last reply

### Could a superconductor make a perpetual flow of electrons with the presence of a magnet in the cold vacuume of space? Answered

I just thought of this question and it has been a while since I studied superconductors.

Question by nerd7473    |  last reply

### Is there really a theory behind the hojo motor scam? Answered

I ran into it on line.  More truthfully, it ran into me.  I've never heard of it.  I do know it's a scam, you can't spend \$100.00 at the hardware store and build a device that supplies 120 volts at 2oo amps to power a house.  The whole thing did pique my curiosity, just like a gasifier or hovercraft or flying lawnmower would.  The problem is that if you try to find just information on what the thing is all you get is page after page after page of scam sites or people trying to sell plans for some mythical device. The only thing I've been able to ferret out is that it's some kind of perpetual motion device that will power my whole neighborhood if I spend 9 hours building it.  I like to think none of my fellow humans are silly enough to believe that. Anyway, without trying to tell me you have one powering your house and an orphanage out of kindness or trying to sell me plans please explain the theory behind it.  Sorry if I sound grumpy, I've been battling scam sites trying to look legitimate for the last hour.

Question by AngryGuy70    |  last reply

### perpetual motion machine/device...

Ok, me and my friends were chatting on im on diff ways and ides for perpetual motion machines and i decided to make a forum about it. here is probably the best one, make suggestions, comments, and add your own ideas. ok, you have a tractor trailor or and vehicle for that matter, and you attach a turbine to the top with a fan/propeller/paddle like on the boats at busch gardens that catches air and spins faster as you pick up speed. once the driver has reached the desired speed, he turns the engine off and pulls a knob like on a lawnmower that gets the blade spinning from the motor, but in this case, it gets the wheel axel spinning from the fan thing at the top. the air/wind from the speed of the vehicle spins the fan thing, which spins the axle that spins the wheel that keeps the wind/air coming to the fan up top. if you think this will work, have any comments, or, can even test this out!(i dont have the recources) feel free to post your result or anything else you want to say. i will check and reply :)

Topic by A.C.E.    |  last reply

### how to build a perpetual motion motor?

Question by mcart3    |  last reply

### "Good Time": The Joseph Ducreux Translation

It's been a while since I put one of these out. This one is a parody of Owl City's "Good Time." You can find the original lyrics here. Hope you enjoy! Favorable Circumstances I arose this morn in good humour. Wherefore doth a song authored by Prince reside verily within my mind. Elevate your hands if you favor dancing this eve. For the circumstances are perpetually favorable. I last night slept in my waking attire as if I cared not. I utilised a motorized stage, indifferent to the destination. I shall participate if you favor dancing this eve. For the circumstances are perpetually favorable. Good morn and good night. I shall arise at dusk. Events will yield acceptable outcomes. We need not even put forth effort, The circumstances are perpetually favorable. (Exuberant vocalization) The circumstances are perpetually favorable. (Exuberant vocalization) We need not even put forth effort, the circumstances are perpetually favorable. I lost my composure, for I once again dropped my telephonic device into the natatorium. I abandoned my inn space and withdrew currency from an automatic teller. Let us spend time together if you you favor dancing this eve. For the circumstances are perpetually favorable. Good morn and good night. I shall arise at dusk. Events will yield acceptable outcomes. We need not even put forth effort, The circumstances are perpetually favorable. (Exuberant vocalization) The circumstances are perpetually favorable. (Exuberant vocalization) We need not even put forth effort, the circumstances are perpetually favorable. (Exuberant vocalization) The circumstances are perpetually favorable. (Exuberant vocalization) We need not even put forth effort, the circumstances are perpetually favorable. It matters not the time nor date; The circumstances are perpetually favorable at that point. It matters not the location; The circumstances are perpetually favorable wherever we may be. It matters not the time nor date; The circumstances are perpetually favorable at that point. The circumstances are perpetually favorable! (Exuberant vocalization) The circumstances are perpetually favorable. (Exuberant vocalization) We need not even put forth effort, the circumstances are perpetually favorable. (Exuberant vocalization) The circumstances are perpetually favorable. (Exuberant vocalization) We need not even put forth effort, the circumstances are perpetually favorable. Thanks for coming! Please leave a comment on your way out :)

Topic by Plo Koon

### Why should perpetual motion be impossible?

Our laws of physics are quite clear when it comes to the impossible.You can not produce more energy within a system than what actually goes into it.And since friction will always be a thing in our real world perpetual motion is simply impossible.With this or quite similar reactions all good scientists end the conversation.We know it is not possible, so why bother...If all that is stopping are laws of physics, then it is time to redefine "perpetual motion".Another term for it would be "free energy" as we would have to draw energy from nothing to keep it moving.Solar cells provide free energy the same way as wind- or hydro generators, we even use waves on the ocean to produce electricity...Perpetual motion seems to be defined by mechanical things and motion only.And free energy seems to be defined as bogus only while ignoring the realities.We simply can't use the same terms for everything if they are in fact totally different things....A motor running off a solar cell would be a perpetual motor if you widen the energy term a bit here.The impossible energy to run the motor comes out of nowhere - our solar cell generates electricity from sunlight.And a simple water wheel in a stream will power a mill for as long as water runs down the stream....Humanity and science say this is not free energy as we take energy from other system to make it move.And of course it is a dead simplification anyways.You get the picture though.So far humanity has only managed to tap into a very few forms of energy out there in any direct form.Solar cells come to mind first of course.In a way they utilise radiation to transform it into DC electricity.Then we have all sorts of mechanical energy transfer, from generators over windmills to the modern recovering brakes in electric vehicles.Last but not least we have heat, steam engines, nuclear reactors and so on.The laws of physics however know a few more forms of energy....We seek out new ways to "generate" more electricity than ever before, like fusion reactors.What we don't seek is understanding what we always had already.All we do it to try to "generate" electricity.It is what powers our world but it is only a tiny fraction of what is possible.We burn fuel in a comustion chamber to make piston go up and down.Only to transfer this motion into a rotary one to finally drive our wheels.Most of the energy available in the fuel is wasted this way.Making it slightly more efficient took us over 100 years....Thinking about using the fuel more directly does not even come to our minds.So why bother to consider any other possible form of energy to drive our world.We are stuck in definitions no one really understands because most of the used terms have more than one use and meaning.We fail to open our minds to other possibilities just because "that's how it is and always will be".Flying to the moon?? Impossible!We did it anyway....Using batteries to provide electricity to entire towns? What a joke!In South Australia they do it anyway and with great success as well.Powering entire cities just from wind and solar energy? Are you joking?Well, companies invest an awful lot of money here and they wouldn't do so if it would not make massive profits...So why again should perpetual motion be any different?At some stage it was hillarious to even think our world would spin around the sun.....

Topic by Downunder35m    |  last reply

### Challenge build my perpetual motion device this is the only one that makes sense PLEASE HELP

Guys please help me out i havent built this device yet but it has to work trust me read my instructable and it should make perfect sense www.instructables.com/id/How-to-build-a-perpetual-motion-device-Gotthard-G/ thanks to all who contribute if you have any questions or theory of why it wont work shoot me an email    mgotthard1@yahoo.com

Topic by BTBAMYEAH    |  last reply

### Where can I get a monopole magnet? Answered

I saw a video on You tube (http://www.youtube.com/watch?v=xR6Qait2JGY), in it he makes a perpetual motion machine using a monopole magnet (a magnet with only one pole North or South).

Question by TurboFish    |  last reply

### Perpetual energy machine idea. Would it work? Answered

Hello, i had an idea today. A light powered by a solar panel that powers itself! You would need a small amount of energy to initiate the circuit's current, but i can only see one way why this could not work: Lightbulbs lose some energy as heat and a tiny percentage as sound. How could you counter this? Heat collectors? Any ideas? I think that I may be on to something here!

Question by The Jamalam    |  last reply

### I have idea for infinite energy!

I have idea for an infinite energy or perpetual motion. I know that perpetual motion is impossible because it contrary with firs and second law of thermodynamics. I have learned those laws on  school too but I asked my physics teacher ( I'm in high school now 16 years old) and he said that it looks possible. The problem is that I'm from Kosovo,and there is no any labs of that type where I can make my experiment. If you have any idea about any of this labs which are interested on infinite energy experiments. I would appreciate your help.

Question by Mrfatjonable    |  last reply

### magnet gravity

Couldn't, with well position magnets, create an orbit around a central magnet? Almost like perpetual motion? I've been playing around with magnets lately, and I've gotten magnets to do 2 full revolutions around other magnets before coliding. Is it possible?

Topic by guyfrom7up    |  last reply

### Is there any existing street lighting that uses perpetual motion as its energy source? free energy would be good right??

Free energy in street lighting might be better than solar energy in street lightings. It just need to have a time schedule in order for it to switch on at night and switch off during the days

Question by RayT58    |  last reply

### Heat.

So I want to make a necklace with a pendant that will always be warm. I dont know how to go about this so if anyone can help thatd be great. I was thinking possibly chemicals but i dont know if thats safe nor do i know anything about chemicals. Id prefer something that once i finish it ill never have to change or switch anything out but whatever works.

### Would this idea to prolong battery life work? (NOT perpetual motion, just extended life!) Answered

A few days ago, I designed a self-charging battery system using a dc motor attached to a rechargeable battery pack that turns a generator via gears, similar to how a car battery works, converting kinetic energy from the motor to electrical energy with the generator and looping back to the battery. I've modified the idea to reduce friction as much as I can so that the motor and generator are directly attached now, keeping energy from being lost to friction between gears. Here's a crappy diagram:    |-----|--------------|                     |--------------|-----|    |       |  Motor       |-------||-------|Generator|      |    | | ---|--------------|                     |--------------|---| |    | |------------|----------------|------------------------| |    |--------------|  Battery      |--------------------------|                       |----------------| I know that 100% efficiency is impossible, I'm not trying to get all the energy back, and I'm not trying to create energy. I'm trying to loop the energy that isn't lost to friction and other factors back to the battery, hypothetically charging the battery up a little to somewhat extend the life. I realize that it will eventually go dead no matter what I do due to the laws of thermodynamics. What I want to know if this would increase the battery life enough to be worth incorporating in a design. (I know the motors should be attached to the battery by two different ends but its actually supposed to be a rechargeable battery pack so one motor is attached to input in to charge the battery and the other is output so the battery powers it. Plus if I tried to draw the wires like that it would've taken forever.)

Question by ALogan97    |  last reply

### Why the hell can't people use Google? Answered

How do I cure acne? Where do I get a 23.5kW amp for a 32" subwoofer? How do I make a 32" subwoofer? Does anyone have the schematics for a perpetual motion machine? ... F@#K... Why does reading questions on Instructables make me want to scream obscenities? Can none of these people do any research, or do they expect to have any inane question that pops into their head answered for them?

Question by omnivaal    |  last reply

### People powered woody garden waste shredder

Would someone please make an instructable for a hand or bike powered 'shredder' or 'chipper'  that doesn't involve welding.  Bahi did a great one, but it requires welding, and we don't have that available. The woody stuff that needs making into much smaller pieces are: orach stems, collard and kale stems, summer squash vines, perpetual spinach roots, tomato stems and Florence fennel stalks (they get to be about eight feet tall each year).

Topic by mole1    |  last reply

### Specific error in trying to post image notes

When I try to post notes on pictures in Chrome on Mac, I just get the perpetual spinning wheel. Notes were working for me in Firefox, but today when I tried to add a note, I got this error over and over: error 400 -- invalid json: { top: 0.22568093385214008, left: 0.692, width: 0.24, height: 0.14591439688715954, text:Mmm. Note the focus, the concentration... the enjoyment. } I tried putting the note in different areas of the picture, but nothing helped. Maybe it's comma related. Aaargh, this grammar thing is killing me. I'll report back shortly.

Topic by susanrm    |  last reply

### Should I....? Answered

I received a PM this morning from someone asking to use one of my instructables project photos in their book. Here is what they wrote: I'm finishing writing a book dealing with sci-fi, and I thought it would be kind of fun to include your photo of your croched USS Enterprise (the first one-- tilted upward) . I have similar Trek artwork, and yours would be fun to add. If I show you as artist, might I possibly have unrestricted permission (all future world editions/languages/derivations/ads), to sell it in my printed book as well as from the book site's down-loadable image bank? Should I? I think it would be cool to have something in a book.  The other question is can I? Since it was entered into a contest and according to the contest rules :9. By submitting an entry and entering this contest, you hereby grant Instructables a perpetual, irrevocable, sublicenseable, worldwide, royalty free right to publish and distribute your entry for their promotional purposes.

Question by ChrysN    |  last reply

### Small generators.

Most everyone here knows (I assume) how the generators work in RC cars and there's an instructable that shows it can be used to output electricity. Elementary science at it's best. If any of you have took them apart you'd notice it draws eletricity from touching the center metal pole. Two little brush/copper/zinic contacts. Basically I've been trying to think of ways to extract eletricity without having a need for them. They cause friction. Uh-oh, a few lightbulbs lit up in peoples minds by now and they're going "oh no not another person trying to beat the laws of thermodynamics and acheive perpetual motion" Yep. As we all know eletricity CAN jump if it's powerful enough and arc, but this doesn't make it too safe either. However it's a small scale model to start out and can be contained so the arc won't be a problem. My other problem is the calculations. They need to be precise. To get it working I need a low rpm generator that will generate high output. For this it requires torque which kinda kicks me, it will also need to use (I assume) rare earth magnets. So basically lets stick with my latter problem since it's more down to earth. I need a fairly small generator if possible (It can be larger if no other solutions are present) At least the size of a walnut I don't plan to make anything immense in size as I lack the funding. As pointed, small is key. Not to be redundant but to paint a clearer picture. It will also need to generate decent voltage at a low rpm speed. I cannot emphasis this enough because it's one of the key parts to make my idea function. Hum... Yeah that about covers it. So if any tech wiz's are out there that know of such thing I'd apperecaite it if you'd part the knowledge to me :P I'm also very aware that perpetual motion is eh, impossible... by current standards. The intention of this project is to deepen my knowledge and figure out why things won't work, figure out solutions and on so forth. A learning project for now and perhaps one day it might become something far more awesome.

Topic by Dark-half    |  last reply

### ID/Creationism trolling an academic requirement?

This could explain a lot. (From RichardDawkins.net via Slashdot )Apparently, the course on "Intelligent Design and Christian Apologetics" at Southwestern Baptist Theological Seminary has, as a requirement worth 20% of the final grade, "(4) provide at least 10 posts defending ID that you've made on "hostile" websites, the posts totalling 3,000 words, along with the URLs (i.e., web links) to each post (worth 20% of your grade)."The next time I see a lengthy, ad-hominem-laden, scientifically dubious argument for Intelligent Design on this site I'm going to wonder whether it is a college student fulfilling course requirements by trolling. I notice that reading the replies to your 3,000 words of propaganda isn't required. Now we just have to find whoever it is offering photocopies of Tesla's secret notebooks and plans for perpetual motion machines if you post enough stuff supporting overunity HHO generators.Note to those so inclined: this is not flamebait, I'm reporting a piece of news relevant to this community (because of our semi-regular flamewars debates about ID etc.). Flames will be reported as spam and subsequently ignored. Intelligent Discussion will be welcomed.

Topic by PKM    |  last reply

### Need honest opinions on Single Malt Scotches under \$100 (Preferably from Scottish folks)

If you recall the dialog from the movie, "My cousin Vinnie," the guy says, "No self respecting southern would eat ready made grits."  There is something to be said about his statement.  It is emphatic and pretty much gives away the sentiment from a southern (USA) point of view. Now relate this to the Single Malts.  Can a statement be made, "No self respecting Scot would drink Glenmorangie," or whatever.  You see, my friends and I are having this perpetual debate over various Scotches, available here in the U.S. and under \$100.  One of us made the comment that Macallan is over rated.  Yet, others think that Macallan sets the bar as high as it can be in that price range. No pun intended. My local liquor store carries a fairly good selection.   I notice the following as being bought on a regular basis using a total non-scientific observation: Glenfiddich Glenmorangie Glenlivet Highland Park Macallan Cragganmore Balvenie Cragganmore Springbank Lagavulin Ardbeg Laphroaig So my Scottish friends, please help me out here with your expert opinion on this topic and tell me how you truly feel about these brands.  Make BOLD statements. Thank you.

Topic by kabira    |  last reply

### Existentialists, how do you find a meaning for life? Answered

Lately (and by lately I mean for a while now) I have been experiencing existential/nihilist/teen angst. I'm totally detached from reality, especially the future which is what I'm supposed to care about, what everyone cares about. I think that life is essentially meaningless, it came to exist because of a fluke, and it continues to exist because perpetuates itself (evolution). So I've been trying to make life matter to me, existentialist style. But I can't seem to get the knack of it. I don't know what I want out of life, I'm not clear on what exactly there is to want....I'm not even sure that anything is real except me. Lately I've taken to telling myself that things are meant to be, and there is a greater purpose, I just can't comprehend it yet.....which may be the most ridiculous thing I've ever told myself..... I know most people think this stuff, but don't take it seriously. They just go on living. But I just can't....perhaps because these abstract thoughts seem as real to me as everything else (not very)? Sorry if I'm totally incoherent.... HELP. please?

Question by november21    |  last reply

### LED Outdoor Stair Lighting

Greetings. I'm a poor graduate student - in pharmacology - and I can tell you a lot about how drugs work, but I hardly know a damn thing about electrical circuitry. All I remember is that the robot kit my dad bought me as a kid didn't turn out the way it should... Anyhow, I've been faced with a small problem: the back staircase to my apartment (the main entrance as far as I'm concerned) is scary craggy and doesn't have any lighting. I considered just using a christmas strand of LED lights to illuminate the thing, but there is no outdoor outlet on the house.. I then tried using a solar powered garden light set, but it was pretty much useless (couldn't charge fast enough) up until the point when roofers tossed a bunch of crap on the solar panel and smashed it. So I'm wondering if there's a way that I can keep my staircase lit perpetually (solar panel?) or in a way that doesn't require that I change batteries often. I considered using a lantern battery, but 5 amp-hours is what its rated at, and I guess that even with resistors, I'm not going to get that much life over the course of a few hours. Features wanted: Solar (?) charging or low battery turnover Enough light to see the ground over the string of 6+ lights Light meter so that it only turns on after dark? Thanks, Joel

Topic by Devizier

### e150 Full Size Going Green

Topic by teamcoltra    |  last reply

### Sleep deprived brain fart...Solar Panel Lightbox Generator

OK first off let me tell you I don't know much at all about solar panels, wiring, or electrical at all. So to those that want to flame save your breath. Now at 3:30 am my time I woke up and since I couldn't sleep logged on to Instructables because something was bothering me. The something that wouldn't allow me to get back to the sleep which I craved was the idea for a Solar Panel Lightbox Generator. Now I see the logic in thinking about some of the perpetual motion generators and how they are impossible. And I believe my idea is not possible either, but till I get some info from someone that knows more about electric and solar panels I don't think I will be able to rest. So here is the idea, someone please explain how my thinking is wrong. Build a box of solar panels faceing inward with a light source inside of the box. once the panels start to charge a battery, use the battery to power the light. First off I know direct sunlight is optimal for the panels, but I'm thinking "outside/Inside" the box. How much light does it take for a panel to actually start creating current? How much energy does the light use to create the light? How do you measure how much light (candle power?) a bulb/LED or what ever produces and is it enough to " power " a solar panel/cell? My thinking is if a LED/incandescent/haligion light can produce enough light, with the right amount of solar cells it could power its self after start up. I know things degrade, bulbs burn out and all that. What I guess I'm saying is mathematically could this happen? Since I know so very little about solar and electrical in general is it possible? And if it's possible could more panels be added to make more power than it uses? There's my brain fart, feel free to point out the flaws so I can get some sleep tonight.

Topic by RedneckEngineer    |  last reply

### Grid Tie and Induction Motors

Yes, I know it's nearly 3am on the east coast... but and idea struck me. So the idea is to feed small amounts of mechanical power into the power grid. Not necessarily run the meter backwards, but supplement power consumption.I've researched grid tie inverters - which are very expensive. For those wondering, a grid tie inverter is feeds mains power back into the grid by syncing phase angle and phase (no dead shorts :) ) and applying slightly higher voltage. They are very efficient and really not within a college student experiment budget :pSo I was thinking... Rather than go from mechanical to DC to AC to grid - go from mechanical to AC to grid VIA an induction motor. As a proof of concept, use a DC motor + battery to turn an induction motor. Plugged into the grid, in theory, should apply current. Oh, but the phase you say? How do you prevent a dead short?"I've thought of this -- before applying mechanical power - have the grid bring the induction motor up to speed. Then try to turn faster (apply a torque) with the DC motor, for example. In theory, the amount of extra power put into the grid will be related to the slip angle of the motor - which will also control the speed of the input (so you can't go over speed by too much).Keep in mind that this whole battery business is just a proof of concept sort of thing - I'm not talking perpetual motion or any hohaa craziness. In the end, the final mechanical input will be around 200 watts. I expect this to be very low efficiency (likely 50%ish), 100W isn't an answer to the energy issues - but it's an experiment. It's also not going to come even close to driving the meter backwards, but it should run (as supplement) my laptop + two to three 13w CFL's :DI think the theory is feasible -- the inspiration comes from flywheel driven UPS systems. An induction motor is driven while mains power is on to keep a flywheel in motion. When the power goes out, the FW drives the motor and feeds to local grid.I'm thinking of using a "low" rpm induction motor.... If I recall, ceiling fans are 16 pole? So that's 60Hz2*2/16=450rpm... Add ceiling fan motor to the list of things to hunt for :) Looking at the one above my head, it looks like it even has a nice bolt pattern for some sort of pulley shenanigans :DCan someone either throw some ice water on me and slap me for being an idiot -- or let me know if I've found a boat to Valhalla.Oh, and my apologies for dancing around the "mechanical input" details.... There's a reason for this, I promise :) In any case, insight and information is appreciated :)

Topic by trebuchet03    |  last reply

### BJT vs MOSFET? Answered

-- background: In my perpetual pursuit for designing the best, cheapest, & best performing flyback (line transformer) driver, I've decided to try out some big BJTs, which appear to have higher voltage & current ratings @ considerably lower cost. In the past, I have tried MJE3055's, which work OK, and allow the generation of thin blue arcs from a 12V supply for a few minutes until the transistor dies due to high voltage kickback or overheating. The FDP33N25 gives good results but is somewhat unreliable at 24V. So I decided to give these alluring "PHE13009" 400V 12A rated NPN BJT's a try. However driving the transistor adequately seems to be the problem. (I didn't realize these transistors would require like 5A base current w/ only HFe of 2!) It seems like almost all the "good" driver schematics utilize large \$\$\$ FETs or even IGBTs, but almost every CRT, plasma globe, and ballast (SMPS) I took apart seem to prefer high power BJTs probably due to this exact cost difference. I was only able to get simalar performance to my 33N25 MOSFET when I stuck an additional TIP120 in as an additional darlington stage, which worked very nicely (white hot arcs) for about 1 second, then it popped! :( Since the collectors are tied together they are all exposed to >200V transients, I am sure that's what killed it. I substituted that transistor for another PHE13009 to see what would happen and with a third driving stage (2N2222) I could get somewhat acceptable results but I know I can do better. >:) - My actual questions:  * The GDP of this transistor is 40MHz, seems fast to me. (certainly faster than the 2MHz GDP of the 2N3055 which works well in my slayer exciter.) and MOSFETs have significant gate charge. ECE2630 glossed over transistors mentioning BJTs are faster, (small signal ones, anyway :P ) and some internet sources agree, but I am finding lots of sources saying the opposite! What's the deal? Which one "faster?"  * How to traditional BJTs compare to IBGTs? Which are faster/better? The datasheet for this transistor explicitly mentions its use for "high frequency ballast and switch mode applications" which implies that it is well suited for my needs. It also includes a several inductor test circuits, but other than that the datasheet is pretty bare-bones.  I'm actually a little disappointed the HFe is so low (around 2-3) @ >10A. I may require more windings on my primary and a 48v supply. (not ideal) * I know I will dissipate a little more heat due to the base current, and something I didn't consider was heat dissipated in the resistor biasing/controlling the base. (like 12V at several amps just to drive the damn thing!!) so it is worth the cost benefit of \$0.5? Is there a configuration I could use that makes driving the transistor easier?

Question by -max-    |  last reply

### V-Gate Motor, what is fake, what is real, why is it not possible

Topic by Downunder35m