Wow, that’s four pieces of content in two weeks! Outstanding. Brother, thank you for all the effort you put into this. I really appreciate it.

That transformer is a beauty for sure.

I once built a version of this--admittedly very low precision--to find a short circuit in my sister's car. Just an LM317 some resistors, and a switch to select 10 mA, 100 mA or 1A. Coupled with a cheap Radio Shack DVM, I got 1 mohm resolution, and was able to find the short quickly. Fixing the short, on the other hand, took a day upside down on the floor of the car rooting around under the dashboard.

I literally shed a tear seeing so many uploads. I’m grateful for subscribing to this channel

I bet Pooch is glad you took out that giant buzzer. 😺

It's really fascinating to get explanations for all those different measurement strategies the meters are using internally when my previous understanding from such topics is that accurate measurements require a lot of knowledge I don't have from multiple different physical phenomena including some quantum stuff.

Thermoelectric effect on resistance measurement and compensation.... Just Wow... You are really helping us to get better in the hardware design understanding... Thank You Sir

And now I know how OVC works - thank you!

When you perform the zero measurement, be sure to connect your clips with an interleaved connection stack up of HiSense, LoSense, HiDrive, LoDrive so the path of the 1A current doesn't flow through the voltage sensing path. Try a "proper" zero, then try connecting the probes in alternate stack up combinations to see the resultant errors. Also, when you are connecting to 4-terminal resistors, grab the pair of wires at each end with the clips so each of the 4 clip terminals touches only one of the 4 resistor terminals. Always use the AC current mode to eliminate the thermoelectric and offset voltage effects.

Gorgeous looking transformer !...cheers.

I mean, they might also like Muons, so good that they clarified that.

I've made a portable DIY unit using an 18V Cordless tool battery connected to a DC-DC converter adjusted for CV 3V and CC 10A. With a couple of 2.5mm2 long leads and a DVM mV meter is ideal for chasing the micro ohms in 5kVA 24-48V battery systems or car winch systems etc. I've found 10A is ideal for testing those high-current relays and switches and surprising how relay contacts and high-current switches deteriorate and need replacing or servicing over time. Even testing new high current switches only to find a wide spread in resistance values, and reject some brands due to higher than expected performance.

ohm my gosh

A lot more instruments should have little smileys, that inform you of going over range. A lot more friendly then just a red led

Wonderful. I love experiments after the repair/teardown.

Guessing the purpose of the louder buzzer is for go/no go in a loud environment with hearing protection on. Seems to be set up for a factory environment, with the “😀:Over range” indicator in the bottom left.

I can only dream of owning such a device in my lab... maybe one day, maybe one day. Peace.

SourceTronic seem to rebadge Tonghui gear (as do many other companies), so this would be a rebadged TH2516. Based on comments on EEVblog forums the SourceTronic badged items do seem to cost more, but they also provide excellent support.

Hi Shahriar, thank you for your effort! As usual, great content, also glad you discussed the thermoelectric measurement and compensation. It is a simple but elegant solution measuring directly the thermoelectric voltage, regardless of which materials are being used, and of temperature. At the risk of being picky, at 6:09, that 1% 100 milliohms resistor that measured 110.79 milliohms is actually quite off, it deviates 10%. Also, at 6:49, the 1% 10 milliohms is also off. It should deviate a max of 0.1 milliohm, so a max 9.9 to 10.1 milliohms. I also use these cheaper kelvin alligators, and as you mentioned, you can't use them properly with these 4 wire resistors. At these currents, this is probably the main source of error. Especially considering that later, that SMD measuring 303 microohms is within 1%. The SMD shunt benefits more from the kelvin alligator, since their sense terminals are effectively closer to their power terminals compared to the previous ones. But there is the chance that the instrument is out of cal. Or the slimmer chance that both resistors are off.

Very interesting

If still too loud, stick a self adhesive label over the buzzer's hole.

wow you have amazing skill Sir

hahaha that buzzer is HUGE

nice, four-wire measurement.

It's from Tonghui.

According to the PCB,it's from an instrument company of China named Tonghui(同惠),well-know for its LCR meter. Maybe this is an OEM/ODM product.

I was expecting at least some discussion of the accuracy differences between measuring milliohms between the ST2516 and the 4338B. Yes, I did hear the thermal diagnostic advantage at the end, but what about the actual resistance measurements?

It seems that this is a ratiometric measurement that will make possible to cancel the emf by ovc.

It would be nice to measure that 4-wire resistor with the kelvin clips open, moving the measurement plane inside the resistor.

But what is its output voltage during measurement? It may happen that it is too high for some components.

HI DO HAVE ANY MULTIFUNCTION CALIBRATOR

I would have tried taping over the buzzer to make it quieter before resorting to modifying the board.

What is the value of the resistance when the probes are shorted together? شكرا على الفديو

WTF!! That's not a buzzer. That's an alarm siren!

Believe it or not but I deal with 50µΩ +-2% shunts at work. So there totally is a need for something with this resolution!

dry circuit testing?

What about the temperature that will raise making the resistance shift value?

I thought dmms with auto zero do the same thing to zero out TE voltages or am I mistaken ?

Id just love to have some somewhat good meters that arent from 1969 or 1971 and half defective.

I assume I am missing something, BUT, why the hell is it pushing high current all the time, and not pulsed (something like 20uS at 1% duty cycle), ALL THE TIME! Surely for the INSANE $ thing thing cost they could have precision op-amps stable in that time!