The h Bar

Secret

02:24

journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.067204

Magnetricity applications incoming

John Rennie

04:58

@bolbteppa here:

web.archive.org/web/20070822061059/http://thersa.org/audio/…

Physics Meta

06:19

0

Q: Why was this question considered "big list?"

I recently asked what the most precice measurement we have taken is (What is the most accurate physical measurement ever measured? [on hold]). With 33 views and 6 upvotes, it got mod-hammered as being a "big list," with the implication that I was asking for a long list which has no single answer...

discussion

Novalium Company

07:29

Mood Gorning!

Just finished the final schematic. How does it look?

Problem is, I don't know the values of C3 to C10 and D1 to D12 :P

The circuit is divided into an 555 astable multivibrator, a transformer, a Cockcroft Walton voltage multiplier and a rectifier.

Secret

09:45

arxiv.org/abs/1704.07105

PM 2Ring

@NovaliumCompany It's probably better to put the transformer after the voltage multiplier. The value for the capacitors isn't that critical, you want it to be high, but not too high. I think I used 100 or 250 uF in my ion generator. But they do need to have a high voltage rating. Any diodes that are suitable for use in rectifiers should be ok.

But you really should ask the people in Electrical Engineering. I just had a quick peek, and there was a recent conversation about voltage multipliers. I assume there are people there who've made high voltage stuff, like rail guns, which need a lot of current, so a low current circuit like yours should be simple for them.

Novalium Company

10:03

0

Q: Is this the proper way to create a high voltage (low current) straight DC signal from a 9V battery?

My goal is to create a circuit that will take in a 9V DC battery as input and produce a high steady +1500V DC signal. I don't need high current at all. 1 microamp of current will do. The scheme goes like this: I use an astable multivibrator to generate a square wave. I replace the speaker with...

transformer rectifier multivibrator

@PM2Ring Got it, thanks

Novalium Company

11:48

@PM2Ring What do you mean "high voltage rating"? How many volts?

Novalium Company

12:13

@PM2Ring Nvm about the high voltage rating, figured it out

Emilio Pisanty

@PhysicsMeta @ACuriousMind & other mods, that question absolutely does not belong on HNQ

Novalium Company

12:48

Good afternoon.

I just bought all the components except the transformer. The store lady told me that I am mistaken. I asked for a transformer that converts 9V to around 400V and she told me no such thing exists. So what do I do. She told me to be more specific in what I need so I told her I'd return.

Also the capacitors I bought are polarized. Is that a problem for my circuit?

I told the lady I want a transformer that amplifies the voltage around 45 times and she said they don't sell such transformers. She said they have 9V to 220V or something like that

PM 2Ring

13:19

@NovaliumCompany You aren't drawing much current, so you don't actually need a power transformer. As I said several days ago, I once used an audio transformer connected to a buzzer to generate high voltage. Such transformers are designed to match impedances. IIRC, mine matched 8 ohms to 300 ohms, (so it had a 8 : 300 turns ratio). I assume such things are still easy to obtain. I used to recycle parts from broken radios, etc.

@NovaliumCompany It could be a problem. All the voltage multiplier circuits I've seen use unpolarised caps. What's their voltage rating?

But as I said before, the guys on EE should be able to give you better advice about all of this stuff.

b degnan

14:12

@enumaris Give me a moment to get a reference. There's an IEEE paper, but let me see if I can find something non-paywalled.

Novalium Company

@PM2Ring 63V

b degnan

@NovaliumCompany Your schematic will likely fry your diodes if you aren't careful with the ratings. Also, you have a transformer to a dickson charge pump that you are then rectifing. I would have the transformer before the diode crossbar rectifier.

Novalium Company

@bdegnan Yep, @PM2Ring told me that. Will do.

@PM2Ring So I should ask the store lady for a audio transformer? What specification? (8:300 won't do it, cuz final voltage is 1350, and I need above 1500). What are they likely to sell that will do the job?

b degnan

14:27

The isolation voltage is likely not that high for audio.

you don't want to arc back.

PM 2Ring

@NovaliumCompany You should ask the guys on EE. Work out what you really need before you go off & buy stuff.

@bdegnan Good point, although I managed to get enough voltage to generate small sparks in the output without getting any noticeable arcing in the transformer. IIRC.

Novalium Company

15:17

@PM2Ring Well, I thought I had worked it out. I asked the EE guys a billion times and they said a transformer is fine. You also never told me a transformer would be problem. What's going on?

b degnan

15:51

@NovaliumCompany transformers are isolators. I have transformers that can isolate from 1V to 1MV.

Audio usually only isolates up to 120V-ish.

Novalium Company

@bdegnan So transformer better?

ACuriousMind

16:23

@EmilioPisanty Pinging me here before 6pm on a weekday is unlikely to have any effect ;)

PM 2Ring

16:58

@NovaliumCompany A transformer is fine. But there are various types of transformer optimized for various purposes. A shop assistant at an electronics shop can be expected to have some knowledge of the products they sell, but they may not be experts at electronics.

enumaris

@bdegnan I see you removed your post. If you find a non pay-walled paper just at me and let me know thanks! If you can't find a non-pay-walled paper, the IEEE paper is also good, I can figure out some way...lol.

PM 2Ring

As I've mentioned, my own knowledge of electronics and circuit theory is very rusty because I've hardly done anything with it for several decades. Which is why I suggested communicating with the EE guys.

Emilio Pisanty

blogs.sciencemag.org/pipeline/archives/2019/08/15/…

Cc @JohnRennie

@ACuriousMind got it

ACuriousMind

Well, it will still have an effect. Just not an immediate one :P

b degnan

@enumaris I removed it because it was something else. I accidentally started typing something to Novalium but I was in the wrong language mode. :/ I've asked Dr. Hasler for a document that wasn't paywalled.

enumaris

17:07

:D thank you very much!

b degnan

たまに日本語のフォントが使ってしまう

most of the IEEE things are paywalled. She has other things other places, but she published so much stuff that it's difficult for me to find it.

enumaris

yeah...that can definitely be an issue

a good problem to have though lol

Novalium Company

@PM2Ring Would buying 2x transformers (9V to 220V) and hooking them up work to produce ~440V?

b degnan

@NovaliumCompany no. You have a scaling factor of 1:23. Two would give you $23(23)$

Novalium Company

@bdegnan Yep :P soo what can I do to amplify the voltage ~45x?

b degnan

17:24

how much voltage do you need? 10v to 450v?

Novalium Company

@bdegnan 9V to +1500V

I use a voltage multiplier to multiply the 9V 4x so you get 36V, from there I use a transformer to get it up even more and in the end I rectify.

b degnan

You'll have to wrap that yourself likely. How much current? so, 150x the input.

How many Hz input?

Novalium Company

@bdegnan Very little, around 1 microamp is enough

@bdegnan I use a 555 timer, the control pin is hooked to a 100nF capacitor but I don't know how many Hz is that

b degnan

give me a moment

you'll need to buffer the output. How precise do you need the output voltage?

The 555 can control the output voltage

what are you using this for btw?

Novalium Company

@bdegnan Long story... to control charged TiO2 particles submerged in water with NaOH

b degnan

17:29

two of these in series: digikey.com/products/en/transformers/audio-transformers/…

Novalium Company

Should I be worried about any components frying out? The resistors and diodes seem pretty tiny is size :P

b degnan

Is this a university project? The physics guys will have controlled supplies for this. If the current is low, you won't fry anything.

Novalium Company

@bdegnan Not a university project

@bdegnan The turns ratio of the audio transformer you sent me is 13.68:1. I don't think it's enough to lift 36V to +1500V

b degnan

You need two in series

That's 187-ish

I was looking at a 9V source

1684 with a 9v source with two in series.

Novalium Company

@bdegnan What should I ask the store lady? 2x audiotransformers with around 13:1 ration?

Wouldn't it be easier if I just continued the voltage multiplier?

I think I'll wire up my own transformer, cuz I'm not paint 40$ for two of those :P

Aaron Stevens

17:52

What a great comment here physics.stackexchange.com/questions/497194/…

b degnan

@NovaliumCompany you can use 2x of those audio ones as long as you don't violate the isolation on the output stage to a lower voltage. Audio is cheap. You could just use two and see how it goes. You'll need to be sure that the AC frequency is audio range: 10Hz to 2.2kHz. Make sure that the 555 is outputing a value in that range.

ACuriousMind

@AaronStevens It's not such a rare attitude, cf. also "If you can't explain it to your grandmother, you don't really understand it"

John Rennie

@EmilioPisanty I read his blog every weekend :-)

Novalium Company

18:26

@bdegnan Well, I just tested the 555 timer part on a breadboard and it seems to work, although I am not seeing any blinking on the LED. Is it just too fast?

I found an audio transformer Power: 3W, Resistance: 3 Ohm, 100V will this do the job?

What do they mean by 100V?

b degnan

18:46

@NovaliumCompany That part is a 3mA part, so as long as you don't need more that that, you'll be fine. Regarding the LED, most likely. Do you have an oscilloscope anywhere? that'd be helpful

(keep in mind for high voltage projects, oscilloscopes are super easy to fry if you have the wrong probes. My scope was like 10k, and each probe is 8k.)

I measure up to 20k volts pretty regularly.

You could just use a resistive divider to get 1000x divider to see your output voltage

Novalium Company

@bdegnan No oscilloscope :P

PM 2Ring

@NovaliumCompany Do you have some old earphones? You should be able to hear the tone. Don't use new ones, in case you fry them. :) Alternatively, calculate the frequency. The formula should be easy to find.

b degnan

a $20USD chinese board might save you hours. The earphones are an excellent idea.

Novalium Company

I have a speaker and I hear a tone

which mean it works?

b degnan

you are in audio range, so the audio transformers will work

Novalium Company

18:53

I googled but I still don't quite understand what's the difference between a conventional transformer and an audio transformer. All I know is they have difference in the winding, but what about function?

I tested the 555 timer circuit with a speaker and I hear a tone. That means it's working? I suppose the tone is a square wave?

Aaron Stevens

@ACuriousMind Yeah I know. I just find it amusing that the attitude is "this is physics, so don't bring math into it".

PM 2Ring

@AaronStevens Galileo would be rolling in his grave.

"Philosophy [nature] is written in that great book which ever is before our eyes -- I mean the universe -- but we cannot understand it if we do not first learn the language and grasp the symbols in which it is written. The book is written in mathematical language, and the symbols are triangles, circles and other geometrical figures, without whose help it is impossible to comprehend a single word of it; without which one wanders in vain through a dark labyrinth." - Galileo

Novalium Company

What if math is just another way of sensory perception. In vision, we see part of reality, with hearing, another part. Math can be considered our logical way of perceiving reality

ACuriousMind

Math alone is not a way of perceiving reality because there's plenty of math entirely unconcerned with reality :P

Novalium Company

That part which you say is unconcerned with reality, may be concerned with reality, but we haven't found out how yet. Or we are not congnitively advanced enough yet. Maybe Elon Musk's Neuralink can help xDDD

Aaron Stevens

19:23

@ACuriousMind you mean unconcerned with applied reality :p

b degnan

We are all servants to mathematics; we are all mistresses to physics.

b degnan

19:58

@enumaris here's the paper that I was looking for that shows speech recognition: hasler.ece.gatech.edu/Published_papers/FPAA_Papers/…

@article{george2016programmable,
title={A programmable and configurable mixed-mode FPAA SoC},
author={George, Suma and Kim, Sihwan and Shah, Sahil and Hasler, Jennifer and Collins, Michelle and Adil, Farhan and Wunderlich, Richard and Nease, Stephen and Ramakrishnan, Shubha},
journal={IEEE Transactions on Very Large Scale Integration (VLSI) Systems},
volume={24},
number={6},
pages={2253--2261},
year={2016},
publisher={IEEE}
}

I made a lot of that IC, but I was excluded because I picked a fight with Dr. Hasler. :P

Physics Meta

20:52

0

Q: Unable to Post Questions

I was just now trying to post a question via my Android based smartphone using the App on Physics SE but it is not accepting my question and sending a message stating that we are no longer accepting questions from this user. However I have neither been banned nor held guilty for any sort of misco...

discussion support

enumaris

21:20

@bdegnan greato, thanks!

Sebastiano

F=ma

$F=ma$

enumaris

$F=\frac{dp}{dt}$

Sebastiano

Excuse me to everybody. I'm trying MathJaX extension :-)

enumaris hi

Here MathJaX works. In TeX.SE no.

@enumaris Have you also MathJaX extension? :-)

enumaris

chatjax

Sebastiano

it is the same I think. Thus I can write all formulas :-) using LaTeX<->MathJaX here.

@enumaris Thank you for your cooperation.

enumaris

21:34

mmhm

bolbteppa

22:21

@JohnRennie Amazing! Well done, thanks a lot, what a find!!!

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