Recent Posts

Pages: [1] 2 3 ... 10
1
Transformer (Ferrite Core) / ZVS long cable freq stabilization
« Last post by kreasteve on Today at 02:56:13 AM »
Hi all, I'm new here and to high voltage.

I wanted to build a weed killer. By the way it already exists: https://zasso.com/

Take a look on my picture. (Test with external 24V/400W supply)

I bought a ZVS from Austria with a flyback transformer, improved the heat stability and built some parts around it, included two 1.5m long 40kV unshielded cables. The building process isn't finished: Safety circuits, frontpanel and a few other things are in development.

The problem is, that the generated frequency (normally 15kHz as you might expect) turns to 75kHz if both long cables are connected. I think there is some capacitive coupling over the ground. Can I somehow stabilize the freqency?

Other things I want to say:
-The three parallel SMPS are not the best way to produce ripple free voltage. But they are laying around.
-I should have started with highvoltage earlier. Its very interesting as I notices during the tests. A tesla coil is on my ToDo list.


Tanks in advance!

Best
Steven
2
A pulse discharge with a peak current of 50,000 Ampere is send through a iPod Nano 2nd generation 4GB Pink model. This is a belonging of my back-then girlfriend, now spouse ♥. I did try to explode this on a earlier occasion in 2014, video should be somewhere on the channel in pulse power playlist :)

3
General Chat / Re: What is the guidence on SpaceX rockets based on ? PID's?
« Last post by Mads Barnkob on June 18, 2021, 07:48:01 PM »
In regular automation PID we call that "gain scheduling" and is often used in process startup scenarios or to run with different settings in winter/summer.

You could also look into feed-forward PID if you want a short of "prediction" to not solely rely the process value changing, but you take into account the change of the input variable that will affect the process value.
4
General Chat / Re: What is the guidence on SpaceX rockets based on ? PID's?
« Last post by Patrick on June 18, 2021, 02:48:57 AM »
Is it possible to, based on real time flight data, change the P, I, and D values of a loop to predetermined values know to be more ideal at a particular region?

For instance,

At Angle 42 degrees, speed equal or less than 11m/s P 4.2, I 0.0, D 1.1
At angle 11  degrees, speed greater that 11m/s P 3.7, I 0.1, D 0.7
And so on....

I would plot a g(x) nonlinear function for a micro-controller to execute. like a lookup table.
 or parallel P(x), I(x), D(x) curves all plotted for the micro-controller to pull from using real time air data from Pitot probe/ gps/ interial data streams.
5
Hello everyone,


I took a little break from the PCB design and worked on an issue Syntherrupter basically has since the day it learned playing more than one note at the same time. So far the generation of the output signal happens in real time: if (time > notePeriod): generateOntime(); (overly simplified, but enough to get the idea). The big issue is that any sort of processing elsewhere in the code always has a direct impact on the output. You can test it in the current beta; every sysex command you send to Syntherrupter will cause a short pause in the output. On a smaller timescale, the regular processing which only takes 30-70us is already too much jitter in the output. This is especially noticeable in simple mode. If you play around for a bit you'll for sure find frequencies that sound "not-so-clean" or straight out awful. There's also a limit in how high you can go in the frequency before that blocking limits you.
Oh, and a third issue: if 30us are already too much time, I can't really write "heavy" code (one of the reasons why I haven't touched SD cards and file systems; there may be blocking operations...).

So far for the status quo. I've had a lot of thoughts for how to solve this, including Netzpfuschers suggestion to switch to FreeRTOS. However, FreeRTOS can't solve the blocking and is by far not fast/efficient enough to handle the signal generation via tasks. From all I could find it operates with >=1 millisecond of resolution which is not suitable at all if 30us jitter/delay are already too much. It may make some things easier but it won't solve this issue.
Another idea was to somehow limit the processing to the time after an ontime where it would be the least likely to delay another ontime. However, that doesn't work anymore as soon as you have more than one note.
I also tried to enforce the output generation via fast, periodic interrupts, and that failed greatly. Either the frequency is so low that it sounds like crap, or it is so high that I'm running out of CPU time.

For a while now I've been thinking that buffering is pretty much the only reasonable option. Over the last few weeks I've been working on a buffered solution and now I can say with some confidence that it looks very good. At first I tried to implement ping pong buffers but that didn't quite work. Therefore I switched to one FIFO buffer which works very well so far. When previously the jitter was in the order of tens of microseconds (and well audible), it is now in the tens of nanoseconds range - or in other words: it couldn't be any better. Not only is the jitter gone, sysex processing doesn't cause stuttering anymore either. Currently I'm buffering for 5ms which should be short enough to not be audible. The buffer time will be adjustable through sysex.
Btw: someone mentioned that buffering will take more CPU time than the previous real time solution. And he's absolutely right. The signal generation part is easily twice as complex now. However, I'm nowhere near stressing out the CPU - or in other words, buffering frees up more CPU time than it eats away.

While this is great (and long overdue), there are still issues and glitches I need to track down. I can't tell you when I can release it but the current progress shows that it's feasible so it will be released one day...


Kind regards,
Max
6
Sell / Buy / Trade / Re: LCR meter recommendation
« Last post by TMaxElectronics on June 18, 2021, 01:21:53 AM »
This one is also an option:

/>
Costs around 300$ with shipping and some customs fees.
7
The pulse discharge videos posted in this thread is a part of a series of explosive videos of old phones and electronics. The high voltage pulse capacitor bank, charger and trigger mechanism can be found with pictures, more videos and schematics here: https://kaizerpowerelectronics.dk/pulse-power/4000-joule-capacitor-bank/

A pulse discharge with a peak current of 50,000 Ampere is send through a Nokia 6230 mobile phone. A mobile phone from the era of indestructible handsets, a piece of electronics that would never let you down and yet here it is to die in a fiery explosion of hot-as-the-sun plasma discharge!

8
Sell / Buy / Trade / Re: LCR meter recommendation
« Last post by Mads Barnkob on June 17, 2021, 08:23:57 PM »
Many years ago I just go by with one of the blue cheap Chinese LCR meters, but after Dave reviewed the DE-5000 LCR meter, I figured it was time for an upgrade. It has served me well ever since.

/>
Hi,

the best one I ever used was a HP4263B at my university.
However they are insanely overpriced even when broken.

I got myself a Deree DE5000 and I'm very happy with it.
It has proper Kelvin connections and a wide range of functionality.
I did some testing / comparing with other meters (including the HP) and was pretty surprised by its accuracy.

I tested the DE-5000 up against my broken and taped together blue Chinese LCR meter and was surprised that the cheap one was quite accurate as well!
9
Sell / Buy / Trade / Re: LCR meter recommendation
« Last post by Max on June 17, 2021, 02:51:45 PM »
Hi,


I had to take a similar discussion some time ago and went for an HP4274A. It's a big, old unit but very handy to use. Every function has it's own button, no nested menus, well-readable, large 7-segment display, a range (1pF to 1F with 0.1% resolution) that's larger than the range of many more recent units and the speed is fantastic (~10 measurements per second or ~1 per second in HiRes mode). It also supports biasing the part (useful for electrolytic and ceramic capacitors which are voltage dependent). There's an option for integrated biasing but all devices support external biasing up to 200V.

You can get them "broken" for about 300$ (paid 330$ for mine plus shipping). However, many "broken" units aren't broken. The reason is that the unit shows "Error 4" if no cables are attached. Most sellers don't know that; they'll power it on, see Error 4, and sell it as broken. Of course, you can be unlucky and have a unit where Error 4 comes from actual damage. Service manuals with troubleshooting are available.
For 300$ there're not a lot of new LCR meters that are better than this - except for the size. You really need to have a lot of space for this thing.

I was lucky, I got a very clean, though slightly scratched unit and am happy with it. If you do get one, replace the infamous RIFA cap... it WILL exploded eventually.


Kind regards,
Max
10
Sell / Buy / Trade / Re: LCR meter recommendation
« Last post by Da_Stier on June 17, 2021, 02:01:23 PM »
Hi,

the best one I ever used was a HP4263B at my university.
However they are insanely overpriced even when broken.

I got myself a Deree DE5000 and I'm very happy with it.
It has proper Kelvin connections and a wide range of functionality.
I did some testing / comparing with other meters (including the HP) and was pretty surprised by its accuracy.


Greetings,
Michael
Pages: [1] 2 3 ... 10

* Recent Topics and Posts

post ZVS long cable freq stabilization
[Transformer (Ferrite Core)]
kreasteve
Today at 02:56:13 AM
post Re: Exploding phones and electronics, a mini-series of 50kA discharges!
[Capacitor Banks]
Mads Barnkob
June 19, 2021, 05:30:28 PM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Mads Barnkob
June 18, 2021, 07:48:01 PM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Patrick
June 18, 2021, 02:48:57 AM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
June 18, 2021, 01:22:10 AM
post Re: LCR meter recommendation
[Sell / Buy / Trade]
TMaxElectronics
June 18, 2021, 01:21:53 AM
post Exploding phones and electronics, a mini-series of 50kA discharges!
[Capacitor Banks]
Mads Barnkob
June 17, 2021, 08:27:10 PM
post Re: LCR meter recommendation
[Sell / Buy / Trade]
Mads Barnkob
June 17, 2021, 08:23:57 PM
post Re: LCR meter recommendation
[Sell / Buy / Trade]
Max
June 17, 2021, 02:51:45 PM
post Re: LCR meter recommendation
[Sell / Buy / Trade]
Da_Stier
June 17, 2021, 02:01:23 PM
post LCR meter recommendation
[Sell / Buy / Trade]
the_anomaly
June 17, 2021, 01:58:48 PM
post Re: The dramatic difference between wet and dry sphere splashes
[Science, Research and News In Other Fields Than Electronics]
Mads Barnkob
June 17, 2021, 12:42:03 PM
post Re: The dramatic difference between wet and dry sphere splashes
[Science, Research and News In Other Fields Than Electronics]
haversin
June 17, 2021, 02:49:00 AM
post Re: The dramatic difference between wet and dry sphere splashes
[Science, Research and News In Other Fields Than Electronics]
Mads Barnkob
June 16, 2021, 08:54:32 PM
post Re: The dramatic difference between wet and dry sphere splashes
[Science, Research and News In Other Fields Than Electronics]
davekni
June 16, 2021, 08:00:50 PM
post Re: The dramatic difference between wet and dry sphere splashes
[Science, Research and News In Other Fields Than Electronics]
haversin
June 16, 2021, 05:40:40 PM
post Demo Coil Protection
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
June 16, 2021, 05:39:14 PM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Twospoons
June 16, 2021, 10:20:30 AM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Patrick
June 16, 2021, 07:33:15 AM
post Re: Through-hole layout of UD2.7C universal driver
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dbach
June 15, 2021, 01:21:38 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 15, 2021, 12:02:58 PM
post Re: Through-hole layout of UD2.7C universal driver
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 15, 2021, 06:52:56 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
thedoc298
June 15, 2021, 05:43:07 AM
post Re: Through-hole layout of UD2.7C universal driver
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dbach
June 15, 2021, 05:26:34 AM
post The dramatic difference between wet and dry sphere splashes
[Science, Research and News In Other Fields Than Electronics]
haversin
June 15, 2021, 02:27:03 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 14, 2021, 01:06:02 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 14, 2021, 12:44:31 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 14, 2021, 12:41:33 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 14, 2021, 12:11:13 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 11:52:11 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 11:38:44 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 10:26:51 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 09:57:56 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 09:29:08 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 08:53:25 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 07:22:05 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 07:02:28 PM
post Re: HFSSTC with fixed crystal-controlled frequency
[Solid State Tesla Coils (SSTC)]
Steve Ward
June 13, 2021, 06:25:20 PM
post First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 02:48:59 PM
post OpenTheremin v3 loosing calibration after minutes
[Electronic Circuits]
gianpaolo
June 13, 2021, 12:00:09 PM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Mads Barnkob
June 12, 2021, 07:28:03 PM
post Re: Rocket engine questions
[General Chat]
klugesmith
June 12, 2021, 07:23:12 PM
post Re: Rocket engine questions
[General Chat]
rikkitikkitavi
June 12, 2021, 12:24:06 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Da_Stier
June 12, 2021, 10:06:18 AM
post Re: Rocket engine questions
[General Chat]
plasma
June 12, 2021, 10:01:29 AM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Twospoons
June 12, 2021, 08:47:08 AM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Patrick
June 12, 2021, 07:03:10 AM
post Re: Complications in the design of the first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
PEDRO HENRIQUE
June 12, 2021, 06:42:56 AM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
davekni
June 12, 2021, 04:20:53 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Willsmith001
June 11, 2021, 11:08:24 PM

SimplePortal 2.3.6 © 2008-2014, SimplePortal