It uses a 100uV square wave and goes down to 1uOhm resolution. The connection is indeed 4-wire.
It uses a 100uV square wave and goes down to 10uOhm resolution. The connection is indeed 4-wire.
Is it a square wave or does it alternate polarity? When you say 4-wire, does this mean that the BNC outer conductor is not a screen, but the L/H drive signal, respectively?
Don.R do a teardown of your simpson 444. I always wanted one. I have a Ballantine 3205b instead(I think I paid a bit under 100 for it.) It a teardown is floating around on the forum
And the only aquisition of a otherwise busy weekend was a REVERSE IEEE488<>IEC625 adaptor (Amphenol on the device side, Sub-D25 towards the cable).
The other way round is found more often.
It uses a 100uV square wave and goes down to 10uOhm resolution. The connection is indeed 4-wire.
Is it a square wave or does it alternate polarity? When you say 4-wire, does this mean that the BNC outer conductor is not a screen, but the L/H drive signal, respectively?
Yes. Alternate polarity. Outer conductor is indeed a drive signal (or sense... not sure).
Don.R do a teardown of your simpson 444. I always wanted one. I have a Ballantine 3205b instead(I think I paid a bit under 100 for it.) It a teardown is floating around on the forum
Ok...
https://www.eevblog.com/forum/testgear/simpson-444-micro-ohmmeter-teardown/msg2727236/#msg2727236
My Quadtech Milliohm meter runs unshielded leads two pairs twisted in separate sleeves with a independent ground lead from the box to an alligator clip. The set of cheap and cheerful Chinese ones I rehacked for my bench meters have shields finishing at the main clips but tied the shields together to a 4mm socket.
Side note the Quadtech kicks the but of my 34401A, 34461A and Advantest 6871E much below 10
Depending on what/where you are testing it is worth the shielding IMO but not life ending if you don't have it.
My Quadtech Milliohm meter runs unshielded leads two pairs twisted in separate sleeves with a independent ground lead from the box to an alligator clip. The set of cheap and cheerful Chinese ones I rehacked for my bench meters have shields finishing at the main clips but tied the shields together to a 4mm socket.
Side note the Quadtech kicks the but of my 34401A, 34461A and Advantest 6871E much below 10
Depending on what/where you are testing it is worth the shielding IMO but not life ending if you don't have it.
I did not intend to judge on the merit or necessity of the screen in this application, still just collecting data.
My Quadtech Milliohm meter runs unshielded leads two pairs twisted in separate sleeves with a independent ground lead from the box to an alligator clip. The set of cheap and cheerful Chinese ones I rehacked for my bench meters have shields finishing at the main clips but tied the shields together to a 4mm socket.
Side note the Quadtech kicks the but of my 34401A, 34461A and Advantest 6871E much below 10
Depending on what/where you are testing it is worth the shielding IMO but not life ending if you don't have it.
I did not intend to judge on the merit or necessity of the screen in this application, still just collecting data.
Ask any questions you want about it in my teardown thread. Without a schematic, my knowledge of its workings are pretty slim though.
If one compares high-quality lead-free to high-quality leaded, the lead-free is really only minimally harder to work with, aside from needing a few degrees higher temperature.
I agree with that. Always get high quality lead-free solder from a reputable brand. I'd like to add that lead free solder seems to have a much narrower temperature range over which it leads to good results so the temperature of the soldering iron is much more critical.
medical and aerospace have blanket exemptions from leadfree ROHS requirements. because leadfree puts people and safety at risk.
Hmm, that makes lead-free solder a hazardous substance.
medical and aerospace have blanket exemptions from leadfree ROHS requirements. because leadfree puts people and safety at risk.
I know there are exemptions for aerospace but that's mainly due to the lack of years of experience with the newer materials. The aerospace industry has been very busy figuring out if and how a switch to lead free will impact them for years now. It recognises the "leaded" supply chain is drying up. Leadfree may put "people and safety" at risk although I'm not quite sure those are actually different things.
Aerospace tends to move at a glacial pace on all things. Proven designs and materials only for production stuff.
I got this at a local market for a song ($82 "Texan pesos"). Despite the two scuffs at the front, it is pretty unblemished everywhere else, including its internals.
I really couldn't believe my luck, really. Also, it is spot on against the DMM Checkplus.
(edit) rotated the image.
That's a nice score alright.
If one compares high-quality lead-free to high-quality leaded, the lead-free is really only minimally harder to work with, aside from needing a few degrees higher temperature.
I agree with that. Always get high quality lead-free solder from a reputable brand. I'd like to add that lead free solder seems to have a much narrower temperature range over which it leads to good results so the temperature of the soldering iron is much more critical.
medical and aerospace have blanket exemptions from leadfree ROHS requirements. because leadfree puts people and safety at risk.
No, not any more. The blanket medical exemption ended 5 years ago, and the scope of the remaining exemption has continued to narrow since:
https://www.tuvsud.com/en/industries/healthcare-and-medical-devices/medical-devices-and-ivd/restricted-hazardous-substances
All of the following 875€
6x hp/agilent 34970A Data Acquisition unit with dmm
these come with these cards
3x 34901A
2x 34903A
4x 34908A
Also get Agilent 82357B USB-GPIB Interface cable.
But this is not all. Also get
HP 41800A Probe 5 Hz - 500 MHz.
HP 1153A differential probe.
HP 1152A 2.5 GHz active probe.
HP 1146A AC/DC current probe.
HP 11940A close field probe 30 MHz - 1 GHz.
hp 8447f opt h64 amplifier
And this very cool
Rohde & Schwarz MDS-21 absorping clamp
If someone can tell can if anyone use this in home lab please tell. Never seen something like this
Couple of other small things also. Some meters are almost brand new. Let the selling begins
All of the following 875€
6x hp/agilent 34970A Data Acquisition unit with dmm
these come with these cards
3x 34901A
2x 34903A
4x 34908A
Also get Agilent 82357B USB-GPIB Interface cable.
But this is not all. Also get
HP 41800A Probe 5 Hz - 500 MHz.
HP 1153A differential probe.
HP 1152A 2.5 GHz active probe.
HP 1146A AC/DC current probe.
HP 11940A close field probe 30 MHz - 1 GHz.
hp 8447f opt h64 amplifier
And this very cool
Rohde & Schwarz MDS-21 absorping clamp
If someone can tell can if anyone use this in home lab please tell. Never seen something like this
Couple of other small things also. Some meters are almost brand new. Let the selling begins
Hello, please clarify! Is this only available as one package?
Let the selling begins
Hello, please clarify! Is this only available as one package?
No of course not. And this is not yet sell add. But if someone need something he can send me private.
Just intercepted these two on their way to ewaste.
Unbelievable the stuff that goes to "scrap".
Another save from ewaste, bit dusty but otherwise in very good condition.
Unbelievable the stuff that goes to "scrap".
Yes. And most unbelievable are the cages some of those beancounters build around their 'scrap'.
I bet they get off on the sight of drooling engineers and technicians at those sites, sitting with pervert grins and telling off any offer of money with a ugly sadist 'noooOO!'.
Octupledamnedmotherfeckingarchenemybrainlesstoadshitwankers!
I stood with a colleague in front of one such cage. On top of other stuff there were about ten immaculate CII (pre-Tyco!) vacuum relais freshly chucked in. Two days earlier, I saved the same company hundreds of bucks when that cage was open and I discovered that some other department threw away Pomona 4mm shorting plugs /bridges en masse that I was about to order anew.
Octupledamnedmotherfeckingarchenemybrainlesstoadshitwankers!
I can only agree... Although I have tongue cramps from trying to pronounce it out loud.
I've been at it for years, going where I shouldn't be because when I act like a civilised animal I (almost) always get a straight "NO". (That's without asking too often, the right approach could be to ask 4-5 times a day until the idiots give-up.)
I must admit ther's a little adrenaline involved in the "Fuck you too!" process of going for forbidden trash treasures, besides I do have a slight case of TEA and electro-junk addiction in general.
Where it really gets disgusting is that it's the same way with so many things other than T.E., a minority of wasteful idiots decide goods are going to be destroyed, while that happens the average consumer is being eco-brainwashed into thinking the planet needs saving. (That comes at a cost for the consumer of course... Let me laugh, who cares for ecology?)
got fluke 83 £55
iso-tech icm 2000 clamp meter rs stock no 697-3702 £18