Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires

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Author Topic: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires (Read 59562 times)

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #100 on: 2010-05-06, 00:13:03 »
Group: Guest	Quote from: Peterae on 2010-05-05, 20:36:29 Edit Heatsinks are not connected to anything but the Drain does push up against them un insulated Uh Oh! Having that much aluminum surface area electrically connected to the FET junction is a problem when such short duration spikes are generated. Having the heatsinks tied to the low side of the rail or 'grounded' is my suggestion before doing anything else.

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #101 on: 2010-05-06, 07:44:39 »
Group: Administrator Hero Member Posts: 3961	I hadnt even thought about the insulation on the heat sink, they are black anodized so i guess this does insulate them, with regard to me generating the sharp pulse they are as good as not using a heatsink at all so dont seem to affect it. I better get some insulation to try. The 2 Drain wires are the same length from each fet to the bottom end of the coil. « Last Edit: 2010-05-06, 12:23:20 by Peterae »

szaxx	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #102 on: 2010-05-06, 11:59:09 »
Sr. Member Posts: 276	Hi, 194-760 @ RS components 1700 volt 12 amp with no reverse diode. Quite cheap maybe worth a look. Hope they are not too slow for the project.

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #103 on: 2010-05-06, 12:22:34 »
Group: Administrator Hero Member Posts: 3961	Hi szaxx I have not yet tried IGBT, i always thought they were slow, the specs of this one seem pretty good, my only concern is the off speed @ 220nS, but they are really cheap and worthy of a try when i next place an order. Thanks Peter

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #104 on: 2010-05-07, 03:53:51 »
Group: Guest	Peterae, Here is something for interesting results. You only apply power to the valve heater element. You must experiment with the resistors and capacitor. Attach your scope probe across the anode/cathode. Drive it with an inverter or invert your current drive pulse. You can connect two in the same way you are using your FETs. If you can't see anything then apply a small amount of voltage to the coil in your normal way without an inverted drive pulse. All, No jokes, please. I've already heard them. If you haven't tried this, with interesting results, or a null-voltage audion then you can say you are a tube person but really aren't. This circuit will not work with an 811 or 811A. It works best with Nuvistors like the 8056, 2CW4 and 6CW4. ------------------------ Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires null-triode.JPG (8.3 kB, 300x180 - viewed 525 times.)

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #105 on: 2010-05-07, 09:24:17 »
Group: Administrator Hero Member Posts: 3961	Now that i could build. Not knowing much about valves, so what would be the best device thats a) cheap and b) provides a bit of power. I assume i could use variable resistors for the 2 resistors what sort of values would you suggest and what power rating are they, i could then use a fixed value capacitor (What Value and Volts rating) The driving pulse is that TTL? so i could use an inverter stage as a buffer. Cheers, Peter

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #106 on: 2010-05-07, 10:56:03 »
Group: Guest	You could experiment with the resistors by using a single potentiometer. Size the ohms so you have the correct load applied to the driving gate. The capacitor can start as .01mfd while using low frequencies. This will allow you to see how it runs. The passive devices run the same no matter what switch is used. The function of most tubes are very similar to FETs with the exception that: 1. tubes are not limited to best performance at 'full-on' 2. the source of anode current can be only the energy radiated by the heater (for a very few tube types). 3. the grid not only turns flow on or off but can also accelerate. As far as higher pulse energy goes.... use shorter pulses and much higher voltage and current. Tubes don't break-down as fast as FETs. The needed amplitude of the signal applied to the grid will change with the voltage being applied to the load. i.e.: If the load curve must change then the drive curve may need a change. These aren't normally used as digital switches (but they were the first gated digital switches). I can't claim to be a master at using tubes. Simply, there was nothing else available for me to experiment with when my experimenting began.

Ken	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #107 on: 2010-05-07, 18:09:28 »
Group: Guest	WaveWatcher, Sounds like a tube would be preferable in some instances. Could the semi-conductor devices stop certain things from occurring, which might hinder a successful OU device? I know where there are a bunch of tubes sitting on a garage. I guess I should go see what they are going to do with them. If I do acquire these, I will be asking you many questions as you are the tube guru. And now for the jokes.

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #108 on: 2010-05-07, 22:38:50 »
Group: Guest	Heh?... If I were a tube guru I wouldn't have blown so many into little pieces I just started my bench shenanigans with tubes. I've destroyed too many to claim any expertise. Best to just read up on example circuits and schematics of others. This weekend, I hope to rotate a charge field in a stripped-down magnetron. Guess I'll have to make sure it is pointed away from me Never had OU from a semi-conductor device or tube. Can't claim OU from anything else, either. As far as SS preventing OU... If OU is possible, I doubt it will be easier to do with SS switching. Don't spend much money on old tubes unless you get the 'tube bug'. Grab a few of each general type for games, maybe. Look for direct heater types (no separate cathode) or sub-minies and Nuvistors. Nuvistors triodes and diodes were common in the tuners and video circuits of 60's - 70's color TVs. They are very small and require almost no plate voltage. You can see a picture on Wiki.

szaxx	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #109 on: 2010-05-08, 00:40:23 »
Sr. Member Posts: 276	Having fried all but two fets the temptation is growing as I have a few VHF tubes/valves a 4CX250B forced air cooled and a QQZ04... instant on heater and others but reluctant to use them as they are for 2m and 70cm amps. But .... The 6JS6 pair can be used as they are retired from poor performance at 30MHZ probably too slow for this experiment. If you choose to use tubes/valves apply the heater voltage allowing the cathode to heat up before applying the HT or it will eventually be stripped and dont heat the cathode leaving it with no HT for too long or it may end up poisoned. Just a couple of tips for anyone not too familiar with them. Ive not used them specifically for over 30 years but they may have a use to start with. Now secondary emission..... Sounds kind of familiar now. I wonder if that comment has a REAL meaning, it sure looks that way? Steve.

Ken	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #110 on: 2010-05-08, 01:42:33 »
Group: Guest	I wasn't going to spend any money. I was just going to go ask them if they wanted to give them away. I recall working as a helper on tv's when I was about 12. The only thing I ever did was check all the tubes with a tester. Half the time that was all it would take to fix it. I think all of these tubes are either radio or tv. I recall the tuner tubes, they were always the smallest.

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #111 on: 2010-05-08, 04:04:49 »
Group: Guest	Quote from: szaxx on 2010-05-08, 00:40:23 Now secondary emission..... Sounds kind of familiar now. I wonder if that comment has a REAL meaning, it sure looks that way? No more than what I typed. Secondary emission is why I suggested using a positive pulse applied to the grid. In my small circuit suggestion there is no HT (HV). The amplitude of the output can be controlled by the heater voltage. The output will be extremely small until the right pulse timing is applied. Be aware, my tests were with air-core toroidal windings. The negative connection of the coil can be broken and voltage applied at that point if so desired. If done then a capacitance should be connected across the power supply to complete the coil path for the pulses.

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #112 on: 2010-05-08, 18:42:39 »
Group: Guest	Peterae, Any hardware reason why I can't duplicate the function of you PIC function generator using an 18F4550 & 20mHz crystal? I have a couple left over from a recent project and would like to investigate your results from your perspective. Thanks, WW

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #113 on: 2010-05-08, 20:31:20 »
Group: Administrator Hero Member Posts: 3961	You wont be able to get 1nS res using software. Just build my digital mono, and if you do want to let me know i will forward the pcb files onto you. Or if enough people were interested i could get some pcb's made up and mail them. but you still need a pic to automate the dip settings. Edit that's a real nice chip, i have done some dev on it myself, using a bootloader and a usb lead.

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #114 on: 2010-05-08, 20:45:46 »
Group: Administrator Hero Member Posts: 3961	you also would not get the crackles. I have quiet a complex system going to create the crackles which has to be a certain setup. What happens is as follows. I use a 8 pin pic to drive 3 led drivers, these drive 4 x 7seg displays and 1 8 bit latch, these are all set serially from the 8 pin pic. The 7 seg displays 0-255 nS delay and the 8 bit latch plugs in place of the phase bank of dip switches using ribbon cable. Now when i do a scan i get pockets of instability where my pic starts crashing, but in truth it's not the pic thats crashing, it's the led drivers receiving duff bit's serially, this means the 8 bit latch is also receiving random numbers between 0-255 which also means that the second delay unit is randomly setting the phase to 0-255 nS, the first digital mono is set using dip switches and this one is probably rock solid and fixed and it doesn't really matter as it's delay setting is only relative to the signal generator, once this first channel fires the fet it also triggers the 2nd phase delay which is the random channel. Only once this cycle of instability and crashing do i get the occasional crackle/explosion. To me what this means is there is a certain set of circumstances that created the crackles but only once in a while are the random events correct to do this. So for you to produce this effect you will need to build my setup exactly, pic dip switch driver board, 2 delay mono's and my main fet driver and fet board, only then can i guarantee you will get them, and even then it's hard work as you know. I am Cautious about the valve driver that people are suggesting to me to build as this may stop the circumstances to produce the effect, but maybe also it could make it easier to produce, worth a try as long as i don't have to throw buckets of cash at the valve build. Mean time i wait for my tube of FET's and pray i can get it stable again to capture some data, hopefully with ou guys helping we can iron out what ever is creating the crackles and the conditions needed to produce them.

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #115 on: 2010-05-08, 20:59:43 »
Group: Administrator Hero Member Posts: 3961	One thing also occurred to me, when i ran out of irf840's i switched to a 900v fet, i got the white noise but no crackles, maybe this fet being higher voltage was not quiet able to get the sharp dv/dt that is required to produce the crackles, as it's like a snap or collision of 2 very sharp pulses. The white noise from the coils is an indication i am close to getting crackles, looking at the spectrum plot it's looks more like pink noise but i know nothing When i say white noise i am referring to my untrained ear, i am hearing the sea at the beach, a sort of SHHHHHHH This is present when the crackles are not happening, which is what you see in the spectrum shot without the crackles appearing. Now my theory goes like this, SM was injecting pink noise into his bifilar delay loudspeakers testing for spacial and response when he noticed something on his Spectrum, ie bit like i could see on my Spectrum bands of energy grouped but equally spaced across the spectrum. As i understand it an audiophile well indeed use pink noise

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #116 on: 2010-05-08, 21:32:52 »
Group: Guest	Do you etch your own PCB's? I do unless the design is too critical. So, part of the steps needed to create the effect is random misfiring of inline circuits. It is not totally avalanche on the FET. I had the same problem some time ago. I found the only way to duplicate with control was to use a Brownian noise generator with full adjustment of the high and low frequencies and the slope between them. This one also required an additional white noise generator signal. The spectrographic result was sinusodal clumping(repeated grouping) of both signals. I wasn't hearing explosions, rather a noisy tone. I knew the PIC 18F wasn't fast enough for pulse building but I have the other chips you have posted on earlier schematics. I don't have a display but figured I would just move that function to my bench PC through USB. (It is personally hardened for my experiments and I build software interfaces to PIC firmware, when needed.) If so many exact circumstances are required even exact duplication of your devices may not allow the same results. A change in PCB material, solder, power supply may also may make it impossible. I have seen this before. I need to finish bench cleanup from the previous disaster before proceeding. (I wiped out my isolation transformer and I'm not sure about the performance of my good scope Not from OU research. Just trying to make someone's bad design work.)

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #117 on: 2010-05-08, 21:40:14 »
Group: Administrator Hero Member Posts: 3961	it doesn't always pay to help : Yes i make my own pcb's If you were to build my setup i would use my pcb for the pic, it only uses 1 8 pin pic which is pennys, but you do need this board design to get the correct instability, it's key. I have used different fet and fet drivers and pcb's and still see the crackles. The digital mono is very fiddly to build and is double sided with a lot of small soldering, you would need 2 of these. Originally i used an inverter/ buffer on each digital mono board and then used an inverting fet driver to correct the logic levels, i used this method to help avoid ground noise, but have since taken the buffer/inerter off and used non inverting fet drivers, in both cases i had crackles.

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #118 on: 2010-05-08, 21:48:27 »
Group: Guest	Quote from: Peterae on 2010-05-08, 20:59:43 when i ran out of irf840's i switched to a 900v fet, i got the white noise but no crackles, maybe this fet being higher voltage was not quiet able to get the sharp dv/dt that is required to produce the crackles, as it's like a snap or collision of 2 very sharp pulses. Is either FET not a true MOSFET? True, meaning "Metal Oxide Substrate". Not all use metal oxide. In my experience, only the true MOSFET's are closest to operation and performance of a valve with a direct heater. Don't ask me what that performance detail is. I still haven't figured it out. ------------------- Just read your last response. Perhaps there is a chance I can replicate your results. The smallest PIC I have is a 18F2550. I think it is 22-pin. I'll see what I can find for the display and the correct PIC. Hopefully, I'll be asking for your PCB layout and I can see what you are seeing.

Grumpy	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #119 on: 2010-05-12, 16:40:27 »
Group: Tinkerer Hero Member Posts: 3948 tExB=qr	Lightning Warning Signs Sometimes lightning will give you a few seconds of warning before it strikes: Your hair will stand on end Your skin will tingle Light metal objects vibrate or buzz Metallic taste in your mouth Palms get sweaty Crackling or “kee kee” sound Smell of ozone (swimming pool smell) At night, a blue glow may show from an object

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #120 on: 2010-05-13, 00:35:37 »
Group: Guest	Grumps, I have a little problem with your list of warning signs... Your hair will stand on end - Which one? Your skin will tingle - Your's doesn't tingle all the time? Light metal objects vibrate or buzz - Can't tell. The plate in my head is making too much noise. Metallic taste in your mouth - Hmmm... maybe I've blown-up to many eletrolytics? Palms get sweaty - Uh Oh! I think I'm always in trouble. Crackling or “kee kee” sound - How can I tell this sound from my wife complaining? Smell of ozone (swimming pool smell) - I never smell this anymore but my wife complains I smell of ozone after a few hours on the bench. At night, a blue glow may show from an object - An object? You mean like, not me? At night only? No clouds out tonight but I still feel like I'm screwed BTW: How did you have time to take all these notes before the lightning struck you?

Grumpy	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #121 on: 2010-05-13, 13:21:19 »
Group: Tinkerer Hero Member Posts: 3948 tExB=qr	Quote from: WaveWatcher on 2010-05-13, 00:35:37 Grumps, I have a little problem with your list of warning signs... Your hair will stand on end - Which one? Your skin will tingle - Your's doesn't tingle all the time? Light metal objects vibrate or buzz - Can't tell. The plate in my head is making too much noise. Metallic taste in your mouth - Hmmm... maybe I've blown-up to many eletrolytics? Palms get sweaty - Uh Oh! I think I'm always in trouble. Crackling or “kee kee” sound - How can I tell this sound from my wife complaining? Smell of ozone (swimming pool smell) - I never smell this anymore but my wife complains I smell of ozone after a few hours on the bench. At night, a blue glow may show from an object - An object? You mean like, not me? At night only? No clouds out tonight but I still feel like I'm screwed BTW: How did you have time to take all these notes before the lightning struck you? I found this list on the web and noticed similarities with Peter's explosions. Like I was saying before, the first pulse appears to set the parameters of the medium and the second pulse extracts the goods. You may recall that SM stated that tuning directly on the magical frequency (or delay?) would convert so much energy that the TPU woudl be destroyed - he may have been referring to this explosion effect.

Peterae	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #122 on: 2010-05-13, 22:49:48 »
Group: Administrator Hero Member Posts: 3961	I agree G I have not been able to produce the crackles as loud as i first found them, probably because the conditions are different with this setup, the great news is that probably means last time i didn't have the conditions right either just a bit better, so i wonder what will happen if i can tame the conditions. Now for the good news i had my FET's arrive today, so hopefully i can try again tomorrow to capture the Spectrum shot. It's also interesting that i only get the crackles using copious amounts of feedback, but the feedback is caused by the release of the energy effect itself, when i send the first pulse and then the 2nd i get random impulses back to the fet drivers which causes a mash of rf bursts for a short period, in which sometimes the crackles appears, the noise eventually dies and then comes along another master pulse to start the sequence of events over again, this is clearly shown in the explosions video. The random bursts of noise last different amounts of time each time they occur, and sometimes the crackle appears quiet soon after the second pulse and sometimes much longer, at this point i am not even sure if i need 2 pulses, it maybe just the correct sequence to create the energy release, bit like playing a sequence of notes to form a song. or maybe a sequence of very sharp fast pulses happening in a random fashion occasional have the same effect as mixing 3 correctly phased frequency's that are at presently unknown, but instead of using frequency's as such i am producing the correct mark/space impulses to simulate the same thing as 3 frequency's in the coil or harmonics in the coil. It may just be i have found a random way of finding the correct frequency's to mix to cause the effect SM found.

BEP	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #123 on: 2010-05-14, 04:09:00 »
Group: Guest	Just a thought... 'accelerometer' ...use one to sense/display the acoustic spectrum. One thing I will be doing when I duplicate your explosions - analyze them with my vibration analysis equipment and software. With that I can decompile the FFT into the individual waveforms. (The SM videos don't have clear enough sound on the videos - I tried a couple of years ago)

darkspeed	Re: Controller No 4 - Dual Fet Driver - Looking for Explosions in Wires « Reply #124 on: 2010-05-14, 05:55:16 »
Group: Guest	Quote from: WaveWatcher on 2010-05-14, 04:09:00 Just a thought... 'accelerometer' ...use one to sense/display the acoustic spectrum. One thing I will be doing when I duplicate your explosions - analyze them with my vibration analysis equipment and software. With that I can decompile the FFT into the individual waveforms. (The SM videos don't have clear enough sound on the videos - I tried a couple of years ago) What are you hacking the Fourier with?

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