What did you buy today? Post your latest purchase!

[gamalot]

I bought some banana plugs to make my own 4 wire shorts, copying Fluke's layout is easy, the only problem is that they use 2.5mm PCB, I plan to use two PCBs stacked.

[RAPo]

On the local craigslist I bought an "Isolating amplifier switch" from ELWE  model M35.
It seems to be an apparatus that can present 3 signals on one scope channel.

[rdl]

Crucial 1TB SSD, CT1000BX500SSD1 on sale for $65, which is just about the only reason I could come up with for buying it.

https://www.amazon.com/Crucial-BX500-NAND-2-5-Inch-Internal/dp/B07YD579WM/

[jonpaul]

Bonjour a tous:

Weekend at flea market and street sale in Paris...

ensemble: lot was EU25!
Lamps: Osram prof. flash lamp and 1600W Xenon for cinéma projection
Swiss army knife  Arrow T25 cable stapler
Samsung DVD ext USB,
Four vintage dynamic microphones, 1950s..1960s...Beyer, Philips, Italian Geloso, unknown (any recognition?)
3 use DIN or Tuchel connectors, one 4 pin Amphenol 91. a few with cases/box/stand

Your thoughts appreciated!

Jon

PS: unknown USBC thing (what is?)

[paulca]

Oh dear.  I did one of those "Yes, No, Yes, No" and clicked the button.

I mean, it's not going to be stellar, but it's an upgrade in quality of like to the Owon USB scope and the cheap chinese MiniScope I have.

YeaPook 100Mhz (lol) Scope.  It's basically the same as the little tablet one that Dave reviewed a year or so ago.... but with physical buttons and dials instead of just touch screen.

Seems the alt brand is Fnirsi.

£180?  It might be worth it.  Cheapest beyond that is £350 for a Rigol.

https://www.amazon.co.uk/gp/product/B099S4QP3T/

[armandine2]

YeaPook

Not matter what it looks like this should have set some alarm bells ringing. 

[armandine2]

Mind you if it does FRA gain and phase Bode plots  - you've scored.

[Dave]

Your 'estimate' is almost certainly wrong and is based on your conclusion then worked backwards to 'prove' your LSD attempted point.

The error margin is ±20% at most, the estimate is definitely not an order of magnitude off. There is no working backwards or forward, either the number is right or it is not.

The calculation is based on the resistance per square (the seller lists the PCB copper weight as 1oz./sqft). Based on the shape of the copper (counting pixels), I've calculated the resistances between the 4 junctions and from that, I've calculated the portion of the voltage that the sense terminals (right side) see when current is injected into the force terminals (left side), resulting in the resistance observed by the meter.
You can start a new thread if you feel that this question needs a deeper dive (or if you feel like your hunch about my calculations is almost certainly right), I'll happily contribute. I'm done derailing this particular thread for now.

Last time there was a THREAD on this I remember it was in the 10's of nV with this sort of layout well below the LSD on a 6 1/2 digit meter.

The thread you linked talks about that number in regard to a bent solid copper wire short. That wire is also shaped in a way that current between the force terminals doesn't flow by the sense terminals, such as in the product that you've found.

[capt bullshot]

PS: unknown USBC thing (what is?)

Looks like an enclosure for a M.2 SSD. Try to open it and look what's inside - if it is such a thing, they're supposed to be opened to install / remove your SSD.

[DaneLaw]

PS: unknown USBC thing (what is?)

Looks like an enclosure for a M.2 SSD. Try to open it and look what's inside - if it is such a thing, they're supposed to be opened to install / remove your SSD.

Definitely, a M.2 enclosure, looks to big to be a Msata... got a few just like it.
usually comes in two M.2 flavors NGFF (next generation form factor 5Gbps Sata3) or NVme 10Gbps or above..
you can usually see it on the socket and if it takes key-M or Key B... but check if there is an M.2 drive in it.

[Ed.Kloonk]

I have a pair WD green M.2 120Gb (2018?). Works OK in the laptop. Bought a USB enclosure for backup. Keys fit but chipset no talkie talkie to the drive. 

[jonpaul]

RE: USB2 thing:

YES it is an M2 USBC, probably from Alibaba.

BUT hard to open, removing the 4 tiny Philips screws, the wraparound alum shell will not pull off, and the end plates are stuck.

Any advise?

Mille mercies,

Jon

[JohanH]

Collection is coming together.

10 pF ±0.5 pF mica
100 pF ±1% mica
1 nF ±0.5% mica
10 nF ±0.3% mica
100 nF ±0.3% mica
0.5 μF ±0.5% x 2 polystyrene
10 μF ±2% polypropylene
100 μF ±3% polyester

For larger values, the current plan is to use 10% 1 mF (1000 μF) tantalum SMD caps, which are still cheap. In series and parallel to get less deviation of capacitance value and higher voltage rating.

[deadlylover]

BUT hard to open, removing the 4 tiny Philips screws, the wraparound alum shell will not pull off, and the end plates are stuck.

Try pushing the USBC port, pic attached I think it's the same one.

Hmm I want to make a little pencil drawer that attaches to a table...I'm thinking linear rails...this might get expensive.

[beanflying]

Your 'estimate' is almost certainly wrong and is based on your conclusion then worked backwards to 'prove' your LSD attempted point.

The error margin is ±20% at most, the estimate is definitely not an order of magnitude off. There is no working backwards or forward, either the number is right or it is not.

The calculation is based on the resistance per square (the seller lists the PCB copper weight as 1oz./sqft). Based on the shape of the copper (counting pixels), I've calculated the resistances between the 4 junctions and from that, I've calculated the portion of the voltage that the sense terminals (right side) see when current is injected into the force terminals (left side), resulting in the resistance observed by the meter.
You can start a new thread if you feel that this question needs a deeper dive (or if you feel like your hunch about my calculations is almost certainly right), I'll happily contribute. I'm done derailing this particular thread for now.

Last time there was a THREAD on this I remember it was in the 10's of nV with this sort of layout well below the LSD on a 6 1/2 digit meter.

The thread you linked talks about that number in regard to a bent solid copper wire short. That wire is also shaped in a way that current between the force terminals doesn't flow by the sense terminals, such as in the product that you've found.

You are now misrepresenting the OP on that linked thread to suit your argument. The OP produced a solid plate short and some of the feedback below from Dr Frank and others was that they saw no problem with it.What they did do was show some examples of what they had made using a single U shaped termination as one bit of wire is easier than lining up three and then relying on the solder joints to hold the Bananas in place.

Your initial issue was with the 'resistance' of the short on evilbay but then please explain how this is an issue when the Fluke and others use 10mil traces with an almost certainly far higher resistance? The Reason for this is to reduce the thermal issues no more and no less and be of a sufficiently low resistance for the calibration process to work. If you bothered to read the fluke link and try and understand it you would see that Thermal issues play more of an issue with these than absolute resistance.

Added to this that current flow across a wide short trace is not uniform but that is another whole can of worms

[rdl]

I bought The Elder Scrolls V: Skyrim Special Edition from GOG. It was on sale 67% off. I already had it on Steam from years ago, but I really don't like the way Steam is all the time sniffing my butt (metaphorically speaking), so I avoid logging in there as much as possible.

[Jay_Diddy_B]

Hi group,

I bought a Leeds & Northrup 4286 Kelvin Bridge Ohmmeter.

The bridge comes in a nice wooden box.



It has five ranges from 0-1.1m to 0 - 11
The stated accuracy is 2%, which is still pretty good today.

Here is the schematic:



From: https://www.rfcafe.com/references/radio-news/resistance-measurements-january-1946-radio-news.htm

It came with the battery, a No.6 1.5V Cell. It shown here next to an AA cell for scale.



On the 1.1m it uses about 15A!!

I gave it a quick check and it is still within spec.

Jay_Diddy_B

[CatalinaWOW]

Those batteries were still readily available when I was a kid.  I think they were originally used in telephones, but by the time I was on the scene they were used to power glow plugs in model airplane engines.  Hence the name "Ignition Battery".

[jonovid]

Hi group,

I bought a Leeds & Northrup 4286 Kelvin Bridge Ohmmeter.

The bridge comes in a nice wooden box.



It has five ranges from 0-1.1m to 0 - 11
The stated accuracy is 2%, which is still pretty good today.

Here is the schematic:



From: https://www.rfcafe.com/references/radio-news/resistance-measurements-january-1946-radio-news.htm

It came with the battery, a No.6 1.5V Cell. It shown here next to an AA cell for scale.



On the 1.1m it uses about 15A!!

I gave it a quick check and it is still within spec.

Jay_Diddy_B

 large single dry cell batteries with screw tops were used by the P.M.G. The Postmaster-General's Department in 1960s Australia under the Eveready brand for some telephones

Bridge Ohmmeter has classic appeal

[Bud]

Why left dial scale is upside down?

[jonpaul]

Bonjour,

At the  Vide Grenier,  (street sale)  Jussieu, Paris 5eme

Akai ACM-100 condenser mic/case/stand/wind screens NIB EU 5

PSU for Dymo label EU 0.50

Coffee bean grinder, classic Moulinex EU 2 (had bad mains cable)

German Erem #20 long nosed pliers, EU 1 (was a bit corroded, dry joint)

Total money EU =$ 8.50

Hours of fun...

Jon

[Jay_Diddy_B]

Why left dial scale is upside down?

Hi,
The galvanometer is a field replaceable unit. The instructions for changing the galvanometer are included in the lid of the instrument. If you remove the two screws on either side of the galvanometer the assembly can be lifted out. The magnet remains in the instrument:

 


The electrical connections to the galvanometer are through the mounting screws.

It is very sensitivity this with 10uA from a Fluke 5101 calibrator:




The sensitivity doesn't matter, it is used as null detector.

Similar galvanometers were used in other Leeds and Northrup instruments. Some were mounted upside down. I suspect that the galvanometer on my 4286 was replaced with the wrong version in the past.

Jay_Diddy_B

[msuffidy]

Got a Gigabyte RTX 3060 for $526 Canadian after tax. It was the last one on sale and I got it $10 less because someone returned it. I was not thrilled about that but there does not seem to be anything wrong with it.  Can't say for sure it was not used, but it did have the plastic wrap on the led window. The RGB led is kind of useless to me because I still use an old case with no window. I can't be bothered to get a new case so I take the lid off when I am going to full load for a while. That is also a Ryzen 5900X on a gen 1 Ryzen board a Asus Prime B350 Plus. I got the 5900X on sale for like $500 after tax. Mixed 2400 3200 ram. I run 2400 2400 15-15-15-35. One of the CPU fan leds died. Hope that isn't an issue. I am still clinging on to my Audigy2 pci at the bottom there. It goes to a gameport Microsoft Sidewinder.

[Martin72]

Six assortment boxes for my resistors and trimmer - And at last a case for using my dymo labelprinter..

[deadlylover]

Took about a month to get here by surface...oh my god it's beautiful. 

It's a Sartorius MSE2202 balance used from Yahoo auctions Japan, all told it was ~USD130 shipped which is a bargain considering these are in the $2k range new. Should clean up nicely I think they must have used the plastic chassis cover all its life (that has yellowed to hell).

Display is easy to read, boot up time is only 5 seconds so that's not too bad. The response on small additions is excellent compared to a typical strain gauge balance.