Julian's Postbag: #82 - All Quiet in China
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- Опубліковано 6 лют 2025
- Help make Julian's Postbag videos with a monthly donation via Patreon: / julian256
eBay links:
Flexible Stranded of UL-1007 24 AWG wire cable Yellow/Blue/Red/Black 10M 300V www.ebay.com/it...
New C51 4 Bits Digital Electronic Clock Electronic Production Suite DIY Kits MC www.ebay.com/it...
9V Battery Case Holder Cover Box for Active Guitar Bass Pickup Electronics Black www.ebay.com/it...
7PCS Full Type Adjust frequency Screwdriver Anti-static Ceramic Set Hand Tools www.ebay.com/it...
Copper-clad aluminum is actually pretty common in cheap wire. The definitive test is to hold it in a flame for a second or so. Aluminum wire will go limp and wilt, where copper will hold its shape.
I always forget what I have ordered from China by the time it arrives and when anything does I have also forgotten the project I bought it for :)
+Mark whalebone I know that feeling :)
Mark whalebone , while I often forget why the hell I ordered some parts, I also often lose the project I bought the parts for.
Same here. I place an order from china and my parcel doesent arrive for three months....
The wires are probably made of Chinesium.
Benjamin West how many protons?
depends on what the toxic waste they were trying to get rid of was on the day they made it...
OrbitalSP2 13.75 protons, give or take half a quark
Benjamin West .75 lol....only in China these can be manufactured
Chinesium is apparently better quality than Amerinesium that's why you ordered it!
Haha. I love your positive attitude 👍 “I’ve got a spare JST cable!” That’s like buying a car that doesn’t run and proclaiming “I’ve got spare seat belts!”
I love the way you pronounce the names, especially the ones that are phrases :P
"Cool man, love it!" :D
Thanks for the more awesome, Jules!
About the battery boxes,thought you might be interested. Electro-accoustic guitars which have the built-in preamp have a battery box right next to the speaker output. This powers the amp as well as tuners etc that are often built in.
Re the UL-1007 wire, see also UL-758. UL-1007 deals mostly with environmental/safety and refers to 758. Materials used mostly copper, with aluminium, steel used too, But only copper can be tinned.
Those 9v battery boxes are like those used to power active electronics in guitars. Pre-amps/buffers, active pickups in bass guitars, piezo pickups in acoustics with built in tuners/graphic EQs, etc.
Thanks for the interesting chat. BTW, in the US, we say "point for by one point eight" for 0.4 x 1.8mm. "by" instead of "times". And we properly pernunsikate "pf" as "puff". So there. ;) Two countries separated by a common language, indeed.
I, too, have the proverbial "Jones" (drug habit) for all things cheap from Chiwan on Ebay, so it's fun watching you open your mail pouches on the other side of the pond. Cheers!
What about the flame test??? Take a flame to it and see if it glows or melts.
If it glows its copper and if it curls up its aluminum!!! ;)
Zane Revai great idea to try
Yep, Big Clive does that on various LED set wires.
Paul Sengupta Exactly who I learned that trick from!!! ;)
+zane revai if we hadn't got Big Clive eh :)
Ahhh another Postbag Video ... That makes the Friday perfect ;D
Hello Julian. I've built the same clock kit a while ago and when using a 5 volts power supply it keeps time fairly accurately. After 2 or 3 days, there was maybe a 2 second difference between it and my computer clock. But I thought the display was way too bright at 5 volts so I tried 3 volts instead, and to my surprise, after a couple of days the difference was around 30 seconds. Maybe that's something you could investigate after you built the kit yourself.
Ah ok, thanks. I have been warned :)
One thing I have found - the 24MHz version of the chip has a different voltage range - 4.0 to 6.0 volts - not sure if that's relevant.
You have a sharp eye. Even if I had checked the data sheet, I'm not sure I would have seen that there are 2 versions : 12 MHz AND and 24 MHz. So yes you are right, the AT89C2051-12PU operating voltage is 2.7 volts to 6 volts but the AT89C2051-24PU is 4 to 6 volts.
I guess I will test the clock again. 1 day at 3 volts and 1 day at 5 volts.
When I was a young boy, we used to collect copper wire from the dump grounds. Of course we tested it with a magnut to see innitially if it was steel or copper, then we did the torch test. Take a blow torch (we used the old pump up white gas ones) and put the flame to the wire. If the flame changed from blue to green, it was copper. As far as that wire, I recently dug in my back room for some thing or another and ran into a bunch of old printer cabes for Mac's i tore them apart and removed some very high quality wire, the colors were very vivid red black blue yellow and green the wire is copper strand and about the same size as the stuff you ordered. I have used it to make several projects with no problems at all. You gotta love those guys at Apple for the quality they put into every aspect of their product. Perhaps I am a bit prejudice as I am typing this on an aging Macbook pro that, despite it's age and low speed processor 2.4 ghz core 2 duo processor and only 2 gig of ram, she is running smoother and quite a bit faster then my HP laptop with a 2.7 i-7 with 16 gig of ram running windows 10. Simply amazing o me, that this old pelter can surpass a much newer machine. I even have an installation of Linux on the other machine yet I am much more pleased with OSX on the mac.
I like to have a good supply of both stranded and solid wire. That said, my pocket book is in the stage of frozen for awhile due to some financial setbacks. So when i found myself in need of stranded wire, I dug in my back room which serves as as storage room now, and found an old CAT 5 cable which had the head broken, and stripped the outer insulation off, and had my multi-color stranded wire. When examined, it proved to be very high quality wire of good copper material. When the need for solid wire arose, I found an old length of inside house wire, removed the outer covering and I had 6 colors of solid copper wire, again of high quality, all much better then what you get from China. For smaller construction needs, I have used old SCSI cables, again very high quality. When the need arises for lacquered copper wire, I hit my box of recovered wire from transformers and inductors taken out of old burned out or obsolete pc power supplies, I think I still have a dozen or so back in my storage area that can be torn down for more wired. As a matter of fact last week I went on an antenna building spree, used some old cable Tv cable to make a 103 inch CB Base Station Antenna, and used some recovered copper wire from those power supplies to make a 1/4 wave outdoor antenna for my 2 meter Ham radio. So I guess the old saying, "if there is a will, there is a way" still applies to old farts with little funds.
Re DSO138 - Replacing JP3 with a choke made with 4 or 5 turns through a ferrite bead is also recommended to improve decoupling.
Julian I'm a broadcast engineer in America and I use those same ceramic screwdrivers to tune FM transmitter exciters. I've broken 2 of them so far. The tips break under too much stress
The colour of Cuprum is by far my favourite. Forget blues or anything standard, the reddy gold is beautiful.
I've used 89c2051 for some undergraduate projects in ye olden days of 2007 and 2008. Definitely an older one. Can't believe it's still in use! It's the 8051 architecture. I don't know my AVRs very well. Are they the same thing?
The Atmel 89c series were based on the Intel MCS-51 architecture, which was prety much the standard before PIC's and AVR's
You could put the wire in a mix of HCl and H202 and if it's copper, it'll color the solution green.
If you have Nitric Acid, you could simply put it in, having NO2 gas created would indicate copper.
Re DSO138. In the original version ADCIN (U1 pin 10) only used about 0.2V of span so noise was very high. The new version reduces value of R11 to 150R to increase analog gain by 10:1. ADCIN now uses 2V of span so noise is 1/10 original.
If you use the new resistor value (R11=150R) you must update software to Version 50 (113-13801-050).
Funny you have that wire arrive I am waiting on mine arriving from alice too. 10m yellow hopefully solid, instead of the stranded. Unlike the other listings it didn't say stranded.
Good job you didn't use that JST connector on your scope, it's reversed.
Yeah, just noticed the reverse connector on the DSO138. I might unsolder it and turn it round.
This wirestripper ist the best i've ever had. Absolutely recommended !
if you look up the UL1007 wire specification, it is stated that it is indeed/should be tinned copper wire!
I have always avoided the dice project but now I want one so bad I had to order it. Like in all my electronics books when I was a kid, that was the page I never spent any time on, so the page is mint. LOL
i always keep battery terminals from battery powered devices.replaced alot of corroded terminals that way.never throw the contacts away.they come in handy
I have switched to banggood for electronic parts. Ebay is just dumping garbage, whereas, banggood has independant fault reporting. ie if the supplier sends out garbage, the supplier gets kicked off. so it seems.
I don't want to start a mad dash but I've been getting better prices on Banggood than even Ali lately myself. Everything does have to be individually checked though.
Decent replacement for the Qidian QD-184-SX is it's big brother QD-188-ALT !
I thought about typing one hundred Ks but then thought better of it 😊. Congratulations on reaching 100k! Love your videos. They are informative, inspirational but most of all entertaining!
How do I tell which version of the DSO138 I have??? I don't want to finish building it with the flaw inside, not when I could just fix it as I go.
I just started building mine a few days ago and I had gotten to step 5 when my cheap Harbor Freight iron stopped melting solder period. So I am grateful that you mentioned that this exact project I'm building might need a quick fix, especially since I'm only on step 5. ;)
This fix might not be that effective as people think. I now have two DSO138s (one original and one from SainSmart) and any of them shows similar or less noise Julian has with his device.
Good pot trimming tools can be expensive and quality is hard to find find. what are you using ? Regards Chris
The 89C2051 is decades old as a design. It's 8051 based with just two of the normal four 8 bit ports. I cant remember if they licenced the architecture of intel or reverse engineered it. The 89C variant was the later variant (flash) and there was originally an EPROM version (82C2051?). I believe they were considered obsolescent in about 2005.
Wow, pretty old school.
I think the China retailers sell from many member names. It's terribly odd when I search for an item and a dozen retailers in a row have exactly 3 in stock.
Julian, does the scope pick up less noise if you power it with a non-switching PS, e.g. direct battery or maybe linear regulated supply? (Wondering how good the input power filtering is on the DSO.)
I heard you talking about a new version of the DSO138 oscilloscope, wich didn't have that problem, is that the DSO150 or what?
I'm considering buying one of these oscilloscope's.
Would you recommend me buying one by the way?
Does it take solder well? If not, might be Alu.
That's the same clock kit Big Clive built a while back! That's a fun one.
Does it solder well? Good question. I'll try that and put my findings in a future Postbag.
A Big thanks to Big Clive for showing how to set the time on those little clock kits!
The AT89C2051 an older chip? Possibly. I found a document about it in Smithsonian Chips. It was analyzed in unbelievable SEM detail in a 90 page pdf.
Dont sweat it 10:55 a good part of these el'cheapo china parts are semifaultyproduction-runs where tacy sellers are flipping them further overseas.
and many of these sellers knows that, and also just reimburse when compaining.
cant say with this, but ridicalus the amount of items i have got where its obvius with fundamental errors that it would newer pass any kind of quality control., but on the other hand it also insane the price for some of these items.
That 89C2051 is an 80C5x compatible chip, they're ancient but still incredibly common.
Does the wire take solder?
I don't think I have ever had such a good laugh with you over the 9 Volt Batt holders. Experienced same. Of course I would gladly trade a few of these mistakes for earlier delivery, some off my orders are taking much longer than the estimated times. Who has 60+ days to wait on an item? :P
If you can easily solder to it, then it isn't aluminum. Copper, steel, or iron all take solder well. You could try measuring the resistance of a (long) length of a single strand, and knowing the thickness you could then make a good guess at it's composition based on the resistivity. If you have a friend with access to a gas chromatography rig, you could analyze the scrapings and find out for sure.
The AT89C2051 is an Atmel 8051 type uC
The most common cheap cables are CCA - Copper Clad Aluminium. There's an aluminium core and a thin layer of copper for solderability and to fool your eyes. I've seen idiotic things advertised, like "99.9% OFC 2.5mm² speaker cable CCA", which is designed to fool you into thinking it's pure oxygen free copper... And many people don't pay attention to that "CCA" at the end, not knowing what it means and not willing to find out.
Of course it can be tinned on top of the copper and look exactly like on your video, giving a trace of copper-like colour when scraped.
The easiest test would be to put it into a bit of muriatic or sulphuric acid. Solid copper does not readily react with those acids, whereas aluminium will "dissolve" rather quckly with bubbles of hydrogen appearing.
Aluminum is actually #3 on the list of metals that conduct electricity the best. (Silver is #1, and Copper is #2). If you bump up to the next gauge thicker an aluminum cable is as good as copper in current carrying ability, yet is still lighter in weight. That's why they are used for power lines. So the product isn't quite as bad as you'd think, but you do have to use the right gauge wire.
The trouble with aluminum wire is galvanic corrosion when used with other standard electrical hardware. That issue has burned down many people's houses too.
There are aluminum rated outlets, switches, and breakers that can be used safely. The use of aluminum wire inside of houses is a thing of the past, however it was common in the 1970's and '80's. I rewired most of a house I owned from Al to Cu myself. Ironically, only the low amperage circuits (20 or less) are a problem, the higher current circuits are actually safe with aluminum because the high current rated connectors are built to handle this material correctly.
i was gonna say to try the electrolysis method to see if you'll get any Cu2+ ions in water. Cu2+ is blue. but yeah, maybe the flame test is easier to do
I get a strange deja vu looking at that clock kit again.... BigClive just did one too, I had a similar one as well but the pcb and interface was slightly different
Some av cables I recieved from china were copper flashed steel. Found that out by accident with a magnet based light.
Couple questions:
1) How do I know which model of DSO138 I have? I built mine last spring.
2) How do they isolate analog ground from digital ground? I didn't know they were different!
Definitely copper.
You also can tell if it is tinned copper or aluminum. Aluminium won’t take solder.
Cheap wire is probably Aluminium, has a high electric conductivity, is cheap and is used as a replacement for copper wire. You can check by melting it and measuring it's melting point.
After you melted it you can find it's density by dropping it in a glass of water and measuring it's displacement.
Yep, Clive has a lot to say in his videos about the Chinese using aluminium wires.
The hookup wire is probably tinned copper.
Funny coincidence: I had trouble taking a decent photo of my project a few minutes ago due to it being overcast. LOL
I had to immediately order a set of those screwdrivers! So much better than prodding at them with a metal one.
The atmel chip is a retired architecture, but is however a commonly cloned 8bit MCU from General Mao. It should belong to the AVR family of chips though, from what I can recall.
May I ask whether you have an elec degree? I am studying Comp. Sys. Engineering and wondered what your background is.
Nice!!! new Postbag :-) i love it
Julian, do you know which version cured the poor digital ground? I just ordered a kit from Ebay and, as always, who the hell knows what version I'll get ;)
What should I be looking for (board revision?) or won't I know until I solder it up and test it?
Use suphuric acid. If copper, it will turn blue. Easily available from Amazon as drain cleaner.
The shape of that screwdriver is interesting because they look _very_ similar to a cheap-o dollar set of moderately-good metal screwdrivers.
I wonder what design they're both trying to rip off?
Any hint on which new powerbank (with higher voltages) you have ordered? Looking for something like that myself.
Julian question for you mate, why are you showing items purchased in dollars. Is it cheaper on eBay US version.
Isn't solid/stranded tinned copper part of the UL 1007 specification?
The 89C2051 is an 8bit ATMEL microcontroller with the Intel 8051-family instruction set.
Interestingly, UL1007 (iq.ul.com/awm/stylepage.aspx?style=1007) doesn't actually specify the conductor material.
Ah, I recline corrected. I saw a manufactures spec sheet somewhere listing 'tinned copper' with the other UL-1007 characteristics of their wire, but should have gone to the source as you did.
for the wire, use HCl which will dissolve most metals but not copper
Does a magnet stick to these or they a really made from copper?
Julian, do you think these ceramic screwdrivers could be used on the tape head azimuth screws without breaking? Thanks!
I reckon so, they seem quite tough.
First off I love this channel Julian, good job. My question is how on earth can these distributers make money by offering free shipping. I don't think I could mail those rolls of wire one state over for under 2 dollars. Obviously they make some money but it must be miniscule.
Sales from China to my country Italy is really crap, could take over 50 days and more than half the times it gets intercepted by customs and we pay about 40% for customs, VAT and customs clearance assistance.
Your country sounds almost as bad as mine is with VAT and Excise. I normally work out the cost of the item, let's say R1000-00 and then just multiply it by 1.8 to get what I would have to land up paying the day I "Eventually" get a notification it has finally been cleared by customs and found its way to the post office, which in most cases is around 3 months after I have ordered the item.
So basically, around R1800-00, which I personally think is the biggest rip off of all time, but then again, the government here thinks the coffers are bottomless, and when they eventually see the bottom, they fiddle the Rand / Dollar exchange rate, and get caught doing it, and say "Eish, we didn't know", and then politely increase excise fees. 🤷🤷🤷
Strangely enough, I ordered a pwm battery charger on the 12th May this year. It landed in my country 15 days after I paid for it, which got my hopes up, but as of 12th October 2018 11:24 AM it has officially now been release from customs and is now trapped somewhere in limbo at the main mail centre. 🤦🤦🤦
Do you live in the uk, I was just wondering so then I know the products can get shipped reliably to the U.K., as many sellers say they ship to the uk but they get lost most the time, maybe it's just my luck
Hi Julian
I'm a long time subscriber. I stumbled across your channel a few of years ago and while I have very little knowledge or experience with electronics, I still find you and your videos fascinating. Even if I don't understand what your on about most of the time, I love it when a new video of yours pops up in my subscription feed. Just watching you I have figured out what resisters and capacitors do, still trying to figure out transistors though.
I have two questions if I may.
1, Could you recommend a few kits that would help build a basic understanding of electronics?
2, Have you considered doing a Beginners Guide to Electronics series? (I can't be your only subscriber who doesn't know what your on about most of the time)
Ok a third question, What do transistors do?
Roger
Thanks :)
1. Any kit which I describe as "easy".
2. Thought about it, but I'd get bored doing it, and that's not good for anyone.
3. Transistors amplify current :)
Julian Ilett Thanks for your reply.
1, Ok thank you
2, Fair enough, no point doing something you won't enjoy
3 How? They can't just create more energy! It had to come from somewhere surely?
3. Ah no they don't produce current. A small current flowing on one side allows a large current to flow on the other - current is consumed on both sides.
+Woddawic BigClivedotcom did a video on electronics basics a while back. Afrotechmods has a whole series of videos, each concentrating on a specific component, advancing from basic concepts to specialized variants.
Transistors are like solenoids, or better, water valves. They don't create new energy, they use small signals to control larger ones.
+Markle2k Cheers, I'm subscribed to BigClive already, I always loved taking things apart as a kid. I'll check out Afrotechmods
So a transistor is just a relay switch then? I remember them from High School
What is the thing with Julian Ilett on it I see in every video and I want to know what it is?
Is it a flash light with your name on it?
Thanks for loving my comment :)
Have your found a replacement for the QD-184-SX?
Still for a few quid more you can get 100m fully compliant wire with free next day delivery from RS.
You pay your money your money, you take your choice.
Is RS a global supplier? What I like about eBay (and Chinese suppliers in particular) is that everyone can play along, regardless of what country they're watching in. I may dip my toe in the Aliexpress waters in the fullness of time :)
"is RS a global supplier?"
Yes they are www.rs-components.com/index.html
But do they have free shipping in all those countries, with no minimum order value?
Touché
Only 443 to go! then onward to a million.
I wasn't being combative - I just want to give everyone watching equal access to the toys.
Julian, try to use Open Broadcaster instead of CamStudio for screen capture. In my opinion, OBC makes that much better and with less stress for the system.
I'm using OBS and without the webcam picture of me, my PC can just about cope.
Well... It looks like you're using a potato instead of a computer to do your internet stuff... (:
As far as I know, OBC tries to use video card's internal capture feature, but that won't work for very old or internal videocards (like Intel HD crap), of course.
BTW, I have an original JYE Tech DSO138 which stopped working properly recently. It shows correct waveform and able to correctly detect frequency of the signal, but the amplitude shows much smaller than it actually is. That happened after I tried to squeeze the device into acrylic case, and the board got bent a little. I'm a total noob in electronics, so I'm searching for any help to solve this issue. Can you suggest where on the board to start looking for such a problem? Thank you!
Hmm, start with the sensitivity switches.
+Julian Ilett Coupling and sensitivity switches work as they should. Software reacts to changes, shows correct voltage step value and zooms signal wave accordingly. But it feels like the signal is at least half of what it should be when it reaches the measurement `sensor`. I also tried different probes with no improvement. I think I'll have to open the device schematic and trace the signal through all of the components on it's path.
I've purchased and assembled SainSmart DSO138 to replace failed original oscilloscope. It will help me on my way which is not gonna be easy for me.
Those wires were solderable using soldering iron?
Happy 100k !!!
Don't throw away that neat little 9V box, use it for a future project! I never toss anything that can be re-purposed into a new toy doing something completely different. Perhaps an altimeter or something.
It's.... Post Bag!! love it
Your PC is pretty weird. With OBS I can see all dropdowns, everything that is rendered on my monitor.
I guess your PC is still a Pentium 3 or 4?
If I do a monitor capture, the dropdowns show up ok. But I prefer the window capture (so I can cut out surrounding clutter) and that clearly has a few bugs, including the invisible select boxes and cursor misalignment.
Yes, this may be the case. But there should be a checkbox to tell it to include other windows that are in the frame area of your window being captured if I remember right. I have it in German only, but it may say "Record overlapping windows".
I guess that happens because screen capture software captures only the layer the window is located on. Dropdowns and hits render on different layer. But you can also try to capture an area of the screen, which should include all layers.
Yes. There is a checkbox to tell it to just capture all layers, just crop it to the size of the respective window. So it's still window recording but with everything above it, too.
dropdowns definetly are seperate windows in a programming sense, as they have to be able to go outside of the parent window, which isnt possible for child elements. select boxes and cursor too. in window mode OBS takes the graphics object the window is painted on as a direct input. so it works even if the window is partially obstructed or completely in the background
You said "early versions" of the DS0138 oscilloscope had the noise problem. How long ago was that and are new versions OK? Is there a way to make sure one buys the newer version?
Not sure, the JYEtech website doesn't offer a way of telling them apart.
I think I've found a way. From their web site:
*Home | Oscilloscope | DSO 138 DIY Kit*
www.jyetech.com/Products/LcdScope/e138.php
Further down on that page:
skus _13803K and 13804K are newly released improved models with following upgradings:_
_Significantly lowered noises. Comparing: [NEW] vs [OLD] in measuring the built-in test signal._
_Waveform can be saved to and recalled from non-volatile memory._
_Enhencement in Test Mode with auto short-circuit detection capability._
_Supports two types of TFT controllers (ILI9341 and ILI9325/9328)._
I was wondering what the "13803K" was about in SOME eBay listings for that kit. Now I know, it's the upgraded version.
There are no "13804K" listings on eBay right now, but from further research I've found that's the one with ONLY the MCU SMD part pre-soldered, not ALL SMD parts as with the 13803K, so I wouldn't even WANT a 13804K (and don't know why anyone would, frankly).
All of that said, their newest 'scope is the DSO150, supposedly an improved DSO138:
www.jyetech.com/Products/LcdScope/e150.php
The DSO150 skus are 15001K & 15002K - the first has all SMDs pre-soldered, the second has no SMD parts pre-soldered. I'll have to check UA-cam for that model to _perhaps_ get one of those rather than a DSO138 _IF_ the reviews here are good _UNLESS_ you already know that it isn't any good and you bought the DSO138 instead for that reason.
IIRC aluminium will not take to solder (not sure about alloys but just aluminium definitlely won't!
aluminium wire is weird and a bit evil, but easy to test for - try tinning it :)
Good video Julian...Lots of stuff, like electronic kits and small parts coming out of China are a really great deal and good quality. But like your battery pack, I see a lot of JUNK coming from there as well.. I will buy there $10 and under boards, kits, Arduino parts but I never buy their capacitors or almost anything they assemble. However, for us electronics nuts buying form Asia is MUCH better than touring a Radio Shack 20 years ago.. LOL
Best to ya, Glenn
AT89C51 is the micro controller version of the classic 8051
looks like it's copper clad. try lighter burn test. if its copper it shuld not bend only glow red
To quickly see if something is copper (or gold, silver...) and don't mind ruining it, you can scratch the metal on some broken ceramic/porcelain shards or on back side of ceramic bathroom tiles (or really fine sandpaper-dark coloured/black works best) and look at the colour of the mark it leaves on ceramic/compare it to the known copper (or whatever metal you expect). Not 100%, but better than nothin.
yes the 2051 is a washed down versión of the 8051 if memory serves
What's with the plastic solar car?
I think atmel used to manufacture 8051 based MCUs back in the day, before they started doing AVRs
They still make them
Yes it should flame green if copper
If anything just put a little bit of the wire in some hydrochloric acid and see how it reacts. If it starts to bubble it's probably aluminum. After that just check the color that's coming off of it and it'll tell you what it is. Blue is nickle, green is copper, red is iron, zinc is a bit weird because it will actually cause some reactions to happen as well since it wants to replace other metal ions so it'll plate out some stuff specifically stainless steel.
Also if it's just copper it won't react right away as hydrochloric acid can't readily break down copper. It however can breakdown copper oxide so if you scrape off all the silver looking stuff and immediately put it into the acid and nothing happens no color change or anything then it's safe to assume it's copper. If you add in some concentrated hydrogen peroxide and it starts to react to make a greenish color then it's absolutely copper.
I suppose Ferric Chloride would work - PCB etchant.
Well that might actually cause some of the metals to switch place due to their differences in reactivity so it would be harder to actually tell what is going on. Just go to the store and pick up some HCl in the pool cleaning or cement cleaning area. It's only a few dollars for a gallon or so. 20-30% concentration is what you need.
+Julian Ilett The CuCL2 generated is itself a PCB etchant that regenerates itself. It only needs oxygen to refresh itself until the acidity starts to wane. At which time, you add a touch more HCl. You never have to dispose of tired etchant.
how do I know which version of the scope I have or am buying?
do them dso138 allow ac aswell as dc and what is max voltage for that one?
Jay Mee ac & DC with max voltage of 50v
Would recommend Clive's video on that clock.
The buttons are not intuative.
This kit is a piece of garbage. I've assembled four different electronic clock kits and this one is the worst. It not just loses a few seconds per day, but also freezes frequently.
My favorite one is with dedicated RTC module with it's own battery, ambient temperature sensor and nice acrylic case.
Anton Mikhaylov I was going to buy that one, but I didn't.
This kit was alright, I ran it off USB and the time was OK, but the buzzer is fucking annoying
Indeed, buzzer should be disconnected if you want to protect your brain cells. Or you can cover it with a piece of tape... Or throw in additional resistor to the circuit. Although the latter doesn't really worth it.
Re: powerbank: Banggood has a "Besiter" power bank with 5V, 9V and 12V output.
12:36 should be next to "quality control" in an encyclopedia.
once upon a time there were 3 battery boxes, then one jumped into the bin...... now there are only 2 battery boxes
Hold a flame under the wire. Copper would turn the flame Green.
5:00 at89c2051 is a derivative if Intel 8051 with flash rom
It's all quiet in China and it will be quiet for a while in a few days around here... without mail deliveries! :)
I'm having a nightmare getting electronics from China at the moment. Very jealous. Only seems a few weeks ago you ordered those ceramic screwdrivers. I've been waiting on my 18650 cell holders since October (was refunded in December and ordered again).
I bought from Aliexpress many chips at the end of October and some arrived yesterday. It's normal
I went a bit crazy on Ebay over the last few months, which means every day is Christmas! All kinds of stuff turns up that I forgot I ordered. The oldest thing I'm still waiting for was 14th Dec, everything else is at least from January, so maybe you just got unlucky.
I ordered £25 worth of stuff from Julian's favourite Alice11o1983 last week, and it arrived on Wednesday.
I guess mailbag translates to "unplugged" art show; but why struggle to visually distinguish Sn from Ag on an overcast day? That's what distraction ad. nauseum is.
Throw the metal shavings in a flame. If they burn with a green flash they are copper.
Does anyone know of any RF amplifier scheme to use at this Frequency Meter? Or do you know where I can find it?
PU2OLT
I know I'm a bit late to the party, but if you're still looking for a pre-amp the designer of the crystal tester has a page (Search for Wolfgang Büscher, DL4YHF) that includes a pre-amp design and links to other designs, and youtube channel TheHWcave has a build video (part 1) that shows how to modify the crystal tester into a pre-amp if you don't need the tester. I've done this and the frequency counter is so much more useful, and really accurate.In other parts he goes on to modify the firmware to improve it, if you're interested in that.
Congrats - you bought some 9v holders that were rejected by the original buyer. Lot's of this on eBay.
The UL-1007 spec says it should be tinned copper
I quickly looked up UL-1007. But I must have missed the tinned copper bit. Cheers :)
An AT89C2051 is an Intel 8051 clone, but with a much faster clock and halved instruction cycle time.