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Messages - Weston

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1
What are the specifications on your gate drive transformer / what does it look like / what core did you use?

The waveforms look like the magnetizing inductance of your GDT is too low (too few turns / core with too low an Al value). A low magnetizing inductance causes a high magnetizing current. The IR drop due to the magnetizing current causes the waveforms to look sawtoothed.


2
General Chat / Re: hat are the newer and "hotter" fields in EE?
« on: May 13, 2023, 09:21:42 PM »
You did not specify what country you are in, which impacts jobs and how college programs are structured.

In the USA at least, for a bachelors program you are not going to be able so specialize in something as specific as power electronics beyond possibly a few upper level classes your 3rd/4th years.

As others said, make sure you get a good foundation through intro classes. Lab/project based classes are typically pretty fun and employers like asking about them in interviews because you often have to actually make something. I would also strongly recommend taking a class on controls/control theory / feedback loops, probably in your 3rd or 4th year.

Regardless of where you end up on the EE/CS continuum, you are going to want to have some microcontroller/embedded device experience. A good understanding of how computers work (command line/linux, scripting languages like python or matlab) is also important and can be a big "force multiplier" because of how it can aid in any design or analysis work.

Electrical engineering is a pretty wide field and demand for various specialities changes with time. That being said, power electronics is in high demand right now with all the electric vehicle and alternative energy work.

3
Aluminum has ~ 1.6x the resistance of copper. At high frequencies where the skin effect comes in to play the difference is less.

You probably wont see much of a difference in performance. A bigger challenge could be making a good electrical contact to the ends of the wire because you cant solder to Aluminum.

Is this insulated wire? Aluminum can have a mildly insulating oxide coating, but I would not trust it for electrical insulation. At least in the USA, Aluminum wire for electrical use is pretty rare.

4
Is there a risetime or fall time requirement? What is the polarity (is the signal bipolar?)? What determines your duty cycle?

1Hz is pretty low, but at the higher end of pulse repetition/lower end of pulse width you could possibly use a NST or something similar as a pulse transformer.

If you need a fast rise or fall time you will need to directly gate a high voltage source. Any sort of switch that can do that is going to be complicated / expensive.

1Hz - 100Hz is slow enough where if you have a high-ish frequency AC source and a voltage multiplier you could just gate the drive for the AC source. The rise time would be determined by the current sourcing ability of the AC source and the fall time would be determined by the load resistance. You could add a parallel resistor to speed it up fall time if needed, but you would be burning more power and possibly impacting rise time.

5
Thanks for the heads up! I went to the one in 2022 for the first time and it was really cool. It took a lot of willpower to avoid buying too many things.

Looking forward to going to the one this weekend!

6
General Chat / Re: Problems with high voltage TEA Air Laser.
« on: December 18, 2022, 10:27:47 PM »
For those who have gotten the TEA air lasers working, whats the altitude and average humidity where you live?

When I was in high school I spent endless hours trying to get this working and never managed to get any laser emission. It was a while ago, so I could have done something wrong, but I remember trying a number of different setups and replicating them decently closely.

My parents house is close to the beach with high humidity and no reduction in air pressure due to altitude. I have always wondered if that could have played a role.

7
General Chat / Re: 300 VDC regulator @ 3 amps
« on: December 14, 2022, 09:40:18 AM »
Could you change the driving transformer so a 400V DC input would be ok?

As Twospoons said, a low loss way of dealing with this would be to have a boost converter input to boost the line voltage to a constant 400V. Basically the same as the power factor correction circuits used in most higher power commercial switch mode power supplies. You might not care about power factor, but it could provide a constant DC bus voltage regardless of the AC line voltage. It could even be universal input, working on 120V and 240V ac line with no circuit changes or switch.

3A at 300V is 900W, which is a lot of power, but there is a wide range of PFC controller ICs you could use. A linear regulator is at these power levels is also going to be complicated and need a large heatsink.

The linear regulator you provided a schematic of does not seem to be close to 900W. If a lower power is ok there are highly integrated PFC ICs that only need the power inductor and a small number of additional components. Here is one example from Power Integrations: https://www.digikey.com/en/products/detail/power-integrations/PFS7528H/5583101

8
Solid State Tesla Coils (SSTC) / Re: Plasma Toroid
« on: November 02, 2022, 07:37:35 PM »
Cool to see this effect! One day I want to own a plasma globe of the right fill and pressure to do this.

We were discussing a video of the same effect on IRC last week:
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The plasma ring is an inductively coupled plasma, as opposed to the capacitively coupled plasma in a plasma globe. There is a decent amount of literature on the effect, as both capacitively coupled and inductively coupled plasmas are used for industrial applications. Inductively coupled plasmas are typically more dense, and are easier to control the location of than capacitively coupled plasmas.

https://en.wikipedia.org/wiki/Inductively_coupled_plasma


9
Dual Resonant Solid State Tesla coils (DRSSTC) / Re: tiny QCW build
« on: October 11, 2022, 10:46:59 PM »
Not really sure what you are asking for feedback on, but my main comment is that 0.1mm diameter wire is really small and going to be difficult to wind. Thats 38AWG wire?. 36AWG wire is about the finest wire I would want to deal with for hand winding, and even that seems pretty iffy.

Your secondary is almost has a 1:1 aspect ratio, and everything is pretty close together. I guess you cant model it directly in JavaTC, but have you considered going something like LoneOceans curved primary https://www.loneoceans.com/labs/qcw2/ it would give better field grading and a lower chance of flash over.

10
Beginners / Re: TO247 mounting
« on: September 19, 2022, 09:58:56 PM »
Looks like a cool idea! I have seen some similar clips in commercial products.

One thing I would be worried about is the compliance of the strap you are using, if its not springy it might just deform under load and not have much clamping force, especially after a few thermal cycles. A spring washer might help.

Luckily it does not require too much clamping force, it just has to be in the right place. A M3 screw tightened to the suggested torque provides ~200+ PSI of force on the area of the thermal pad and can warp the package, as you mentioned. But you really only need 25 - 50PSI on most thermal pads to get the minimum thermal resistance.

11
Laboratories, Equipment and Tools / Re: Getting last joules out of batteries
« on: September 14, 2022, 10:36:37 PM »
There have been one (or more?) attempted products to use a joule thief like circuit to extend battery life in existing products. I don't think any of them were commercially successful https://en.wikipedia.org/wiki/Batteroo_Boost

There is also not that much energy remaining in the end of the battery discharge curve. If the issues is ESR I don't think a boost converter would help much but I wonder if a large capacitor would help.

Regardless, the joule thef is a fun electronics project and circuit to analyze as a circuit design problem. I remember one of my first electronics projects in middle school was a joule theif based flash light using a a small common mode choke I pulled out of a power supply. I was quite proud of it until I think someone stole it on a school trip.

More recently I made a jfet based joule theif that could start up and light a LED down to a ~40mV input, which was enough to be powered by a flame and a few type K thermcouples!

The open source SKY130 PDK has some zero threshold mosfets so I was considering making a similar energy harvesting circuit and submitting it to one of the open source IC tapeouts, but I am a bit burnt out on IC design stuff at the moment.




12
Electronic Circuits / Re: Induction heating II: Shifting the Phase
« on: August 23, 2022, 08:04:35 PM »
Really cool work! I really like the isolated gate drive power supplies. This looks like it should be a really capable high power system.

When the plant parameters vary a lot you sometimes see controllers that can dynamically reconfigure the control loop, but that is hard to do with an analog controller.

Having the cross over frequencies for the two controllers be at widely spaced frequencies should work. When you are seeing the system oscillate is it at conditions in which there would be reduced spacing between the cross over frequencies of the two control loops?

Cascaded control loops, like in average current mode converters, are easier to model than this, where the control loops are operating in parallel. The active control loop will change the response of the plant for the other control variable. Your approach of measuring the open loop response for the current loop while the phase loop is operating sounds like a solid approach, its the first thing I would try.

Can you just move the cross over frequency for the power control loop to some very low frequency? I assume if you want the power factor to be good it already has to be less than the AC line ripple frequency.

13
General Chat / Re: Aluminium Nitride Thermal Pads
« on: August 16, 2022, 09:24:00 PM »
I think the graphite sheets are intended to be soft enough to deform and fill the gaps, same as the silicon pads. For a material that does not flow like a grease / phase change material I assume the pad has to be at least as thick as the deepest concavity to be effective. So perhaps the super thin graphite sheets are not too good.

Perhaps due to this, for rubber/graphite pads there is a strong dependence of the thermal resistance with pressure as it needs to make thermal contact. You can see that in this random example datasheet: https://www.ohmite.com/assets/docs/sink_pad_tim.pdf



For thermal greases / phase change material the material is already in full contact with both surfaces at very little pressure. The thermal resistance is determined by the bond line thickness between the transistor back and the heat sink / ceramic thermal pad. Bond line thickness is determined by the surface flatness, the viscosity of the material, any solid fillers in the material, and the pressure. It seems that for thermal greases there is little improvement as pressure is increased as the bond line just gets a bit thinner. I am not sure what the physics are, but it seems the bond line thickness asymptote in the 10's - 20's of um range as pressure increases. So if the surfaces are more planar than that you can just assume its all thermal paste with no actually contact between the surfaces?



The NREL paper used glass microbeads (same as a large particle size filler) to get controlled bond line thickness and they still get good thermal resistances using thermal pastes, even at a 100um bond line, which would be pretty extreme in terms of surface roughness / flatness. It seems like phase change materials / phase change pads should give good performance for surfaces with pad planarity and bad surface roughness. They should be able to get into even very deep groves in the heatsink while solid pads would not make full contact.


14
General Chat / Re: Aluminium Nitride Thermal Pads
« on: August 16, 2022, 05:56:49 AM »
That sounds like a cool test setup. Interesting that the P-N junction is too deep in the silicon to be accurate. I wonder what the depth of the diffusions are for modern power semiconductors.

What you are describing sounds pretty similar to the test setup that I was reading about in this app note https://fscdn.rohm.com/en/products/databook/applinote/discrete/common/rthjc_measurement_and_usage_an-e.pdf

It's pretty cool that by taking transient measurements of the actual junction temperature of the device they can calculate the thermal impedance of every interface in the package.

I came across that app note because I was curious as to how accurate the datasheet thermal resistance from junction to case was. The naive approach would include at least the thermal resistance of the thermal paste, or would require it be calculated and backed out. But with the method in that app note they can give the true value, so there is no margin in that.

Your experience is really not assuaging my fears on the accuracy thermal resistance values. But I guess its still a worst case value, so I won't be blowing anything up, just missing out on additional performance. I wonder if modern devices still have the same margin in the junction to case thermal resistance. Or is it account for delamination over the life of the device? I only recently realized that thermal cycles are really damaging to the die attach on power semiconductors. In tesla coils that really gets pushed...

I am currently trying to resist the urge to create a test setup similar to what you described / what that app note details. Another project that seems like it would be a great leaning experience but not actually useful in my current projects, or in graduating with my PhD in a timely fashion....


I ordered some thermal pastes and thermal pads from some vendors in China today. It's basically impossible to order any of the high performance thermal pastes / pads in small batches from the manufacture or from digikey. I found a company that sells some thermal pastes in re-packaged tubes, they seem legitimate based on online reviews, so hopefully I will get what I ordered.

I ordered:

Dow Corning TC 5022, which is one of the thermal compounds I previously discussed and has a thermal resistance of 0.06C/W/cm^2

Dow Corning TC 5026, which has a thermal resistance of 0.03C/W/cm^2 and a much lower dielectric constant / dissipation factor than Dow Corning TC 5022. The datasheet for Dow Corning TC 5022 says a dielectric factor of 18 and a dissipation factor of 0.56 at 1KHz. That seems to be so high I wonder if its correct. Or is the resistivity interfering with the measurement?

Honeywell PTM7950 phase change thermal pad, which has a thermal resistance of 0.04C/W/cm^2. Its non-conductive but I cant find a published dielectric constant.


I think that the phase change thermal pads are the way to go, as you don't need to deal with the hassle of the grease. However, thermal resistance is still limited by surface flatness / bond line thickness and the clamping has to have enough compliance to deal with the ~0.1mm change in thickness when the material melts at first heat and gets pushed out.


If you don't want to deal with random Chinese vendors (but then again, thats the only way to get the AlN thermal pads....) Laird TPCM 580 phase change pads are avaliable on digikey and are 0.1C/W/cm^2, but they are a bit expensive https://www.digikey.com/en/products/detail/laird-technologies-thermal-materials/A15405-01/2634225






15
General Chat / Re: Aluminium Nitride Thermal Pads
« on: August 14, 2022, 10:38:37 PM »
Oops, my bad. I just copied the google blurb which was quoting the portion of the wikipedia article for the maximum possible thermal conductivity, which seems to be for single crystal.

The vendor page lists a value of "Thermal conductivity: 190-260w/m.k". My measurement is close to midway between that. Looking at the picture I took I realized the thermocouple tips are a bit closer together than the lines I drew. They measure at 8.6mm apart, which would lead to a thermal conductivity measurement of 205 W/(m·K). Regardless, it seems to be somewhere in the right range and is low enough where thermal resistance is dominated by the thermal paste.

Thermal resistance with thermal pastes is going to be impacted by the thermal conductivity and the bond line thickness, which is determined by the viscosity, particle size, mounting pressure, and surface flatness. I sadly cant find any figures on the surface flatness of the TO-247 package. The AlN plates seem pretty flat and smooth though.

My goal is to achieve around 0.2C/W for the TO-247 interface. The thermal pad area is ~ 1.4cm^2 so I need a thermal resistance of < 0.28C/W/cm^2 for the whole interface. The 1mm AlN thermal pad has a thermal resistance of ~0.04C/W, which leaves me with a budget of 0.12C/W/cm^2  for each of the two layers of thermal paste / interface.

In terms of thermal paste I found two public reports on testing of commercial thermal pastes  https://aip.scitation.org/doi/am-pdf/10.1063/1.5001835 https://www.nrel.gov/docs/fy08osti/42972.pdf

The NREL report is pretty good and they include artic silver in the tests. They measure artic silver as having so-so performance. However, the artic silver product literature claims that the thermal resistivity decreases after a few initial heating cycles, which these tests do not do



Based on these results it seems that Dow Corning TC-5022 would be good with a thermal resistance of 0.05 C/W/cm^2 at 40PSI

https://www.exdron.co.il/images/Products/files/%D7%92%D7%A8%D7%99%D7%96-%D7%98%D7%A8%D7%9E%D7%99-DOW-CORNING-datasheet.pdf

As would Dow Corning TC-5121 with a thermal resistance of 0.96 C/W/cm^2 at 40PSI: https://datasheet.octopart.com/13310-Greenlee-datasheet-14709059.pdf


I am a bit worried about thermal compound dry-out or pump-out and a phase change pad might be a bit better in that regard. Lard makes some high performance phase change pads: https://www.laird.com/sites/default/files/2018-11/THR-DS-TPCM580%201112.pdf

Looking at the datasheet the different thicknesses are all ~0.1 C/W/cm^2, which implies that the bond line is determined by pressure after the material melts and not the initial material thickness. I am not sure if these pads would not have the same issues with dry-out or pump-out given that the material is semi-liquid at operating temperature.

The best solid pads I can find are graphite based. A company called Jones makes some films that are 0.2C/W/cm^2 but you can only seem to buy them on digikey as a marketplace product https://media.digikey.com/pdf/Data%20Sheets/Jones%20Tech%20PDFs/21-655-0200.pdf

Laird is a bigger company but the best graphite films they sell are 0.42 C/W/cm^2 https://www.laird.com/sites/default/files/2018-11/THR-DS-TGON-800%201109.pdf



tl:dr:

Total thermal resistance of < 0.2C/W for TO-247 should be achievable with AlN thermal pad and Dow Corning TC-5022 at a bond line of < 150um, which is pretty large as far as thermal interface gaps go. Lets treat it as 0.3C/W to account for improper application or pump-out / dry-out.

Its a bit of a pain to sort though thermal pads on digikey, but it seems that the best insulating silicone /fiberglass thermal pads seem to be something in the range of ~ 0.6C/W to 1C/W.

 

16
General Chat / Re: Aluminium Nitride Thermal Pads
« on: August 14, 2022, 08:33:16 AM »
Thermal camera is my own. Its a flir E4 I modified the firmware on to unlock full resolution. Pretty useful tool  :)

My initial goal for the BJTs was to use the -2mV/C Vbe voltage coefficient to measure the internal temperature. I quickly realized that power BJTs are very non-ideal at higher currents. I would have to modify the test setup to pulse the power and allow measuring the voltages with a low bias current.

The material is obviously very thermally conductive, I can hold one end of the thermal pad and cut through an ice cube. Even if it's with an order of magnitude of pure AlN the thermal resistance will be dominated by the thermal paste. My initial goal is just to prove to myself its not actually BeO.

The thermal pads I have are 22x28x1mm with a 3.4mm hole. I applied copper tape to both sides of a thermal pad and measured a capacitance between the two sides with my LCR meter. I measured a capacitance of 43pF and a dissipation factor of 0.005. The readings will be impacted a bit by the adhesive of the copper tape, mounting hole, and edge effects, but if I treat is as a plate capacitor I calculate a dielectric constant of 8.7. The published dielectric constant is 9.2 and the loss tangent is 0.002, so I think thats close enough.

Importantly, the dielectric constant of BeO is 6.8, so I can rule out the material being BeO from that measurement.

Measuring the thermal conductivity laterally on the thermal pad is a good idea. I instrumented the TO-247 parts with thermocouples but it was still hard to get measurements because of how fast the heatsink was heating up.

I soldered 2 1206 resistors on copper tape on each side of the thermal pad and clamped the other side against a larger heatsink with some thermal paste and epoxied two thermocouples laterally ~10mm apart. I am just using UV cure epoxy that is not optimized for thermal conductivity but I ran the thermocouples across the entire width to try to get them to equilibrium. They are also pretty thin so not much heat will be conducted away through the wires.

I covered the whole setup in tissue paper to reduce any heat loss due to convection and ran 3W through the resistors and waited a minute until temperature equalized. I measured 46.6C on the top thermocouple and 40.2C on the bottom thermocouple. This is a thermal resistance of 2.1C/W. With a 20x1mm cross section and 10mm distance this equates to a thermal conductivity of 234 W/(m·K). The published value is 321 W/(m·K), so this is close enough where I am not going to worry about it! Might be measurement error, might be variation in the material properties. These ceramics are probably made from a pressed powder so it should not be anisotropic. Not seeing anything in literature about the material being anisotropic except for very thin films.


Happy to say that this material seems legit! Not to promote some random vendor, but here is the listing I bought it from: https://www.aliexpress.com/item/3256801164656742.html . I am also waiting for some TO-220 thermal pads I ordered off ebay. I would expect all the vendors to be selling pretty similar material.


As the limiting factor with AlN thermal pads is the thermal compound, does anyone have suggestions? Is pump out / dry out something you need to worry about anymore, or has it been fixed with the more modern synthetic compounds? CPUs still use thermal compound, so it cant be that bad an issue. I would think that the thermal compounds sold to computer enthusiasts would be pretty good but I can't find datasheet's for the most popular brands  ::)

The graphite sheets are pretty interesting, without running complicated thermal models I am not really sure what benefit the increased X-Y plane conductivity is though.

The best solid sheet I can find to replace thermal grease is this graphite sheet, which is only 25um thin (!!).

http://www.tglobaltechnology.com/uploads/files/tds/T69-25.pdf

That has to be a typo? I am not sure how I would handle material that thin and not get creases in it or anything. Even then, its 0.14C/W per cm^2, which is about 3x worse than some thermal compounds I have seen. If my goal for the TO-247 package is 0.2C/W total thermal resistance though that might work in place of the thermal grease.


17
General Chat / Aluminium Nitride Thermal Pads
« on: August 12, 2022, 04:31:17 AM »
I recently discovered you can order aluminium nitride ceramic thermal pads for TO-247 / TO-220 parts off of Alibaba express / Ebay. They are only about $1 each too. Shipping from China takes a while though.

If these thermal pads are anywhere near the thermal conductivity of bulk aluminium nitride they should be the best thermal pads you can buy by a wide margin. This would be especially useful for hobby power electronics stuff where people are trying to push as much power through a part as possible.

Unlike the silicone conformal pads the aluminium nitride pads require thermal grease on both sides, which will increase thermal resistance a bit. But bulk aluminium nitride with the geometry of a TO-247 thermal pad would have a thermal resistance of 0.02C/W. Based on datasheets for thermal greases I can find online it looks like the thermal grease would add ~0.05C/W per side for a total of < 0.2 C/W.

For comparison the best insulating silicone / phase change thermal pads I can find are > 0.8C/W and those are pretty thin and easy to have arc over as well as having a high capacitance to the heatsink. If you have a good heatsink the thermal resistance of those insulating pad is going to be the dominant thermal resistance in the system, so the aluminium nitride thermal pads represent a big improvement!

As these thermal parts are from alibaba express and you can't get them off digikey or from western suppliers I am a bit suspicious (although western companies regularly use aluminium nitride as the internal insulator for the big power semiconductor modules). I had my TO-247 thermal pads arrive in the mail today and as far as I can tell so far them seem to be true aluminium nitride. I am going to see if I can figure out an easy chemical / density check as it is pretty hard to get good measurements of thermal conductivity without a good test setup.

I set up some power BJTs in TO-247 package on a small heatsink and compared the aluminium nitride thermal pads to some alumina thermal pads. The heatsink is too small so everything starts to equalize pretty quickly, but it does seem look like the aluminium nitride thermal pads (lower left) keep the part cooler than the alumina thermal pad (upper right), so I have a rough upper bound on the thermal resistance.


18
This looks really interesting!

Whats a polarity sensitive powder / how is it made? I am not familiar with the term.

Does each particle contain an electret material or something and then it orients with the electric field polarity?

19
Voltage Multipliers / Re: To doorknob or not to doorknob.
« on: April 18, 2022, 09:47:35 PM »
Ideally there is not much of a difference between doorknob capacitors and ceramic disk capacitors. They are both disks of ceramic dielectric that are metalized on both sides. Doorknob capacitors are a bit nicer because the screw terminals are more mechanically robust. I think they get used a lot because they are more common as surplus and easier to reuse due to the screw terminals.

The biggest difference would probably be the dielectric material of the capacitors. The performance of the CW multiplier is dependent on the capacitance. A higher capacitance will lead to a lower voltage drop under load. Most ceramic capacitors have a dielectric that has a dielectric constant that decreases with applied voltage. This can lead to a significant reduction in the capacitance at voltages that are an appreciable portion of the rated voltage.

A lot of the low cost disk ceramic capacitors or doorknob capacitors (probably anything from china without a datasheet) use something like a Y5P dielectric that looses 75%+ of its capacitance at rated voltage and temperature. Doorknob capacitors may be a bit less cost optimized and have a better dielectric, but you cant really know without a datasheet. The gold standard here would be capacitors with a N4700 dielectric. You can find them on ebay sometimes. There are a few different product lines by Murata, here is an example datasheet from one.  https://www.vishay.com/docs/22210/715c-kt.pdf

As long as it has a sufficient voltage rating and enough capacitance any capacitor should work.


Whats your expected spark length based on the number of stages and input voltage? There is an upper bound and you might already be getting close to that.

Making a second CW of the opposite polarity would most likely be the biggest bang for your buck. It would reduce the problems with insulation for sure.

Also, if you are blowing up diodes do you have a discharge resistor on the output of the CW? I see something that looks like that in your picture but unless you are grossly exceeding the voltage or current rating of the diodes it should be pretty effective in protecting the diodes.

20
Electronic Circuits / Re: Improve SMPS ripple with electrolytic capacitor
« on: February 27, 2022, 08:34:48 AM »
Its unclear if a giant capacitor is going to actually help.

You really need to see if you can capture some waveforms on an oscilloscope to see what is happening before the supply shunts down. 

Unless you are running very close to the short circuit current protection limit of the power supply I don't think its likely that current surges from the ZVS driver are causing the power supply to shunt down.

One possible cause of the issues is that, as davekni talked about, when you load the ZVS driver too much it can fall out of oscillation and short out the power supply. That could trigger the overcurrent protection of the supply (which is actually saving the ZVS driver from burning up at that point).

Another possible cause is that EMI from discharging the voltage multiplier is coupling into the supply wires and messing with the sense circuitry, causing the power supply to shut down. A giant capacitor is going to have too many parasitics to filter this out but a LC filter, as suggested by Twospoons, may be effective.

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[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 26, 2024, 03:16:03 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 26, 2024, 01:41:49 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 26, 2024, 04:48:22 AM
post Re: Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 26, 2024, 04:16:37 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 26, 2024, 04:16:24 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 26, 2024, 04:13:02 AM
post Re: CM400 Induction Heater
[Electronic Circuits]
davekni
March 26, 2024, 04:00:43 AM
post Re: Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
davekni
March 26, 2024, 03:19:18 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
thedoc298
March 26, 2024, 01:50:42 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 08:05:02 PM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 25, 2024, 07:41:29 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 06:45:46 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 05:44:25 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 25, 2024, 04:47:17 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 04:27:22 PM
post Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 25, 2024, 03:57:34 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
markus
March 25, 2024, 02:06:41 PM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 04:43:25 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
davekni
March 25, 2024, 02:39:40 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 12:47:09 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 24, 2024, 07:36:32 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
Alberto
March 24, 2024, 07:27:24 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 24, 2024, 04:25:23 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 10:47:35 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 09:30:21 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 04:34:31 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 03:04:25 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 01:38:34 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 04:20:03 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 23, 2024, 12:54:30 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 23, 2024, 12:05:57 AM
post capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 22, 2024, 11:45:03 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 22, 2024, 11:30:09 PM
post Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 22, 2024, 10:20:35 PM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Benbmw
March 22, 2024, 09:21:13 PM
post Re: What actually kills MOSFETs?
[Beginners]
AstRii
March 22, 2024, 03:37:11 PM
post What actually kills MOSFETs?
[Beginners]
FPS
March 22, 2024, 05:09:20 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 22, 2024, 03:57:54 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 22, 2024, 02:59:25 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 06:31:42 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
rikkitikkitavi
March 21, 2024, 03:08:01 PM
post Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts
[Sell / Buy / Trade]
Mads Barnkob
March 21, 2024, 01:37:32 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Alberto
March 21, 2024, 11:42:07 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 21, 2024, 04:09:14 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 02:15:31 AM
post My Homemade Structural Analysis X-Ray Machine
[X-ray]
Luca c.
March 21, 2024, 01:35:40 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 20, 2024, 10:40:00 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Mads Barnkob
March 20, 2024, 08:03:41 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Mads Barnkob
March 20, 2024, 07:51:57 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 20, 2024, 10:39:47 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 20, 2024, 04:09:59 AM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 20, 2024, 01:13:23 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 20, 2024, 12:45:16 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 20, 2024, 12:30:30 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 11:12:24 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:47:49 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:44:19 PM
post Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 19, 2024, 06:52:09 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 19, 2024, 05:02:44 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Mads Barnkob
March 19, 2024, 05:01:41 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 04:31:02 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 03:59:54 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 06:41:39 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 19, 2024, 04:05:49 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 18, 2024, 09:08:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 09:07:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
Twospoons
March 18, 2024, 08:57:06 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
MRMILSTAR
March 18, 2024, 03:51:33 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:59:46 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:33:25 PM
post Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 11:02:12 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Twospoons
March 18, 2024, 02:36:11 AM
post Re: Best forum for vacuum tube amplifiers?
[General Chat]
Mads Barnkob
March 17, 2024, 07:42:55 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:15:14 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 05:05:04 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
davekni
March 17, 2024, 04:50:51 AM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Twospoons
March 17, 2024, 04:45:17 AM
post 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:17:51 AM
post Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Terry
March 17, 2024, 01:29:32 AM

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