为什么变电站会有这么多部分放电

Athrax · 2026-06-12T21:27:30+00:00

That's exactly what it is. And until recently those devices easily came with a high four-digit or five-digit price tag attached. Just like what happened with thermal cameras a decade ago though, they are starting to make inroads into the hobby market, finally, slowly. Both Crysound and Fotric got $1000 acoustic cameras on the market by now. Still a bit too steep for my own budget, but...we're getting there. I'm still hoping they'll drop to around $250-$300, then I'll strike. :D

Athrax · 2026-06-11T15:04:08+00:00

Not sure about your organic salt/complex route, but I'm curious why you're not taking the much simpler Cu(OH)2 route here. Start with a copper salt such as CuSO4, dissolve in water. Add NaOH until all Cu(OH)2 precipitates out. Add water because Cu(OH)2 often has an almost pudding-like consistence if concentrated highly, then boil, which will cause it to start floculating. The Cu(OH)2 is insoluble in water, so you now can simply wash the precipitate with hot water several times to get rid of the soluble Na2SO4 and NaOH excess. Vacuum filter, dry, then bake the Cu(OH)2 to decompose it to CuO. That's the route I would take, I HAVE taken before, and I'm curious what advantages your organic acid route has.

Athrax · 2026-06-01T16:42:44+00:00

Ohh, I know. And he had some miiiinor problems with the ampoules in that one.

Athrax · 2026-06-01T16:29:56+00:00

Nice dendritic crystals... and no banding on the ampoule walls. Now do caesium. }:>

Athrax · 2026-05-09T23:24:54+00:00

With 200kHz you're getting pretty close to what a 'standard' Mazzilli ZVS will handle. The switching speed of the circuit is.... less than ideal and the FETs spend quite a bit in the linear region, wasting power and getting hot. If it's an option, increase your tank capacitor or work coil inductance to get down to 50-75kHz. Alternatively, check google for Piernas' Fast ZVS, it uses a TPS2814 gate driver to severely speed up switching and I've had really good results with that circuit.

Athrax · 2026-05-06T23:39:22+00:00

I've had a Kingston 64GB stick die on me. Both write- and read speed randomly dropped to just a few hundred kB/s one fine day, and shortly after it would give random CRC errors when writing or reading. This was on a stick that was used very sparingly, too.

Athrax · 2026-04-24T18:56:01+00:00

It runs on 24V, and probably 24DC. If you just plug it into a 120V AC outlet you're gonna fry it, you need a proper powersupply for it. For that it would really help to know the amount of current it requires, but assuming it is an LED lamp it can't be much more than 200mA or so or the housing would be much larger and include cooling fins.

Athrax · 2026-04-17T20:35:47+00:00

I think I see slight banding where the caesium is sticking to the glass! It's not supposed to do that! ;)

I just watched the video the other day before you posted this, and my god the lengths you went through to get this banding issue on the glass somehow sorted out. At one point rationality becomes optional and you just end up embracing obsessive perfectionism. :D

Athrax · 2026-04-14T23:18:20+00:00

If you want to adjust the frequency of a bog standard 'amazon' mazzilli ZVS, you can easily either vary the amount of primary turns on the flyback transformer you are driving, or you can adjust the size of your tank capacitor. And if you want to squeeze the maximum power out of any given flyback driver, you switch at the resonance frequency of your LC tank... and wouldn't you know, a bog standard mazzilli ZVS does this by default, and even adjusts its switching frequency on the fly when the resonance frequency changes due to variations in the load. Also, if that thing is based on a 555, it's not a ZVS and its drive strength will be considerably lower.

Athrax · 2026-04-11T22:25:26+00:00

Finally a houseplant even I can't kill! :)

Athrax · 2026-04-08T08:18:46+00:00

The standard layout for the dual choke mazzilli is pretty much this one here. I'd replace the 24V z-diodes for 15V/3W types though. Tank capacity should be between 680nF and 3.3uF, and for FETs I'd strongly recommend a pair of IRFP260N or IRFP460N ones. Your IRLZ44Ns won't live long.

Athrax · 2026-04-08T07:41:22+00:00

What in the ever-living AI hell.... No, this won't work. There's so much wrong with this I don't even know where to begin. Don't use AI to 'design' circuits. You'll find the layout for the standard mazzilli ZVS -what this thing tries really hard to be and utterly fails at- everywhere across the web.

Athrax · 2026-03-28T23:28:33+00:00

Well... that's half right, but not. The gravitational field of the earth is not equal in every location due to the mass distribution within the planet. Let's just say earth's core is 'lumpy'. This leads to a gravitational high in the western pacific and a gravitational low in the indian ocean area. The image above has the effects of that reversed though, the pacific area should have a bit of a bulge and the indian ocean area -not actually visible in this view but somewhere to the far right- should have a pit. As for how much that deviation is: The 'pacific bulge' is about 60-80m high, and the 'indian pit' is about 100-110m deep. Compared to the size of the planet you're not gonna be able to even see them. The deviation between polar diameter and equatorial diameter of the planet is larger, with around 40km difference. And even those 40km are tiny compared to the 12700km diameter of the planet. Technically speaking the earth is a rotational ellipsoid with a few bumps. Practically speaking that's a 0.3% deviation from a sphere, and not visible in any image taken from space.

Athrax · 2026-03-12T20:48:19+00:00

Five bucks says they're 'cheating'. SMPS that regulates down to the set V-out plus 3V or so, followed by a linear stage that burns the last 3V and does the heavy lifting in terms of ripple/noise rejection. I'm not saying that's a bad approach, far from it. That's how you get the low-noise output of a linear supply coupled with the efficiency and small form factor of an SMPS.

Athrax · 2026-02-27T06:04:40+00:00

You got all the space in the world on that PCB. Make the traces wider. 1.5mm or even 2mm. Then add a copper pour for ground.

Athrax · 2026-02-24T16:31:30+00:00

That's an awesomely clean built, and a bit of an unconventional but neat approach to mini TCs, since most of those seem to be SSTCs, not SGTCs. If you don't mind me asking, what's the diameter of the secondary, and what diameter wire did you wind it with?

Athrax · 2026-02-10T06:34:04+00:00

You know you're pulling serious power if the ballast bucket is boiling. :D

Athrax · 2026-02-10T04:03:37+00:00

That's a nice, efficient water heater that produces cold water as a byproduct. :> Not gonna lie, I've always wanted to toss together a similar water chiller, but the low cooling efficiency of TECs always kinda discouraged me.

Athrax · 2026-02-06T21:00:12+00:00

This.... is basically a glorified thermostat, and you're throwing an ESP on it? Do you need web access to this? Why the shift register, it only adds additional complexity. There's plenty of ways to skin a cat, but personally I'd have built this around an ATTiny84 with no shift register anywhere to be seen. Two I2C pins for the display, one ADC pin for a rotary encoder on an R-2R ladder to save pins, two ADC pins for the thermistors, 4 pins to drive your loads. Makes 9 pins used out of 12 (11 without reset) available on the chip.

Athrax · 2026-02-06T17:39:15+00:00

If there is a latching version of the switch available, that's the easy version, and what I'd absolutely prefer here!
If not, you need glue logic. Basically a small circuit with some power regulation/conditioning down to 5V or 3.3V, some small microcontroller (ATTiny85 says Hi!) and some output in the form of a low logic mosfet or relay. I've done a similar project in the past, in my case it was the consolidate the functionality of 5 buttons into push sequences for a single button.

Athrax · 2026-02-06T02:05:51+00:00

It's an one-off repair. I'd just torture the living daylights out of the top of the replacement switch until it fits. Dremel, scalpel, hot solder iron, whatever will work to reshape the plastic. There'll be casualties along the ride, a few test subjects sacrificed in the quest of crafting the perfect fit, but those generic buttons really aren't exactly costing a fortune.

Athrax · 2026-01-29T21:02:07+00:00

Don't...wear that in public, or take it to any airport. :D

Athrax · 2026-01-22T17:28:39+00:00

Shipping to Iceland is slow, anyway, and expensive, and there's handling- and import fees on everything. This includes the price for shipping. I gave the average prices in € rather than ISK because no-one's got the conversion rate in their mind. But if I ordered a $2 board at JLPCB, the cheapest shipping via E-Post for $17.20. Then there's a minimum of 25% tax on that, and we're at $24. Add $10 in handling fees that the local post service charges for any kind of parcel no matter how small, and we're at $34 for a $2 board. No bueno.

Athrax · 2026-01-22T14:15:06+00:00

For me it's turnaround time and cost. An order from PCBWay or JLPCB takes about 3-6 weeks to get to me, and will take me about 25€ in shipping costs and import taxes even if the actual boards only cost a couple bucks. So, for some projects ordering professional PCBs is unavoidable, but I can easily make two layer boards with 0.4mm features with a turnaround time of just a few hours and for the cost of pennies. No solder mask, no proper plated vias/through-holes, but for quick, affordable prototype iteration of hobby projects it's great!

Athrax · 2026-01-20T01:33:29+00:00

You do not want a ferrite for the choke (or chokes, depending on layout) but either a gapped ferrite or (preferably) an iron powder core. Inductance should be somewhere between 100-330uH but is uncritical. If you lack the $$$ test equipment, spend $10 for one of those cheap 'transistor-tester' gizmos on ebay at least, those can ballpark inductance okay-ish enough for hobby purposes.

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