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Test Equipment / Re: Heads Up : Cheap Multimeter : Lidl UK (08/02/18)
« Last post by joeqsmith on Today at 08:43:02 AM »
So that clearly suggests that this meter is fully rated for its intended use, with in and on normal domestic use as those fuses will safely handle 10KA otherwise it would not have have received the certification.

I wonder how many times a product has been certified, then the design changes but the company still uses the old cert.   In the case of fuses, that would be a simple thing to replace.   The ones Dave was selling I believe were rated for 10KA breaking capacity.  From Fungus's review, I have know idea if the fuses were even certified or not.  We have to just go on his expert opinion that they are fine.   :popcorn:
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Projects, Designs, and Technical Stuff / Re: Power distribution
« Last post by prasimix on Today at 08:42:20 AM »
Quick search (one that I set faster then wrote down this message) on TI.com returns the following: LM5008, LM5009, LM5018, LM5019. All are switchers, below 2 USD and easily obtainable.
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Test Equipment / Re: Digital Oscilloscope Chart
« Last post by timkoers on Today at 08:42:18 AM »
It looks like you forgot the Siglent SDS-1204X-E, or did you just not put it in there because it virtually has the same specs as the SDS-1202X-E but with two extra channels?
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Test Equipment / EEVBlog BM235
« Last post by timkoers on Today at 08:40:17 AM »
I bought Dave's BM235 a few months ago and I am very very pleased with it. Especially considering my previous meter was a cheap ass one (FX-99MX)

There are a few things that I haven't got an answer too and I couldn't find in the manual.

I am testing my new 'reflow oven' and I noticed that I can't find the max temperature rating for the Type-K probe that comes with the meter.
What is the maximal temperature, or the maximal temperature range of the Type-K temperature probe?

And what is the slot for at the back of the meter, which get's covered by the magnet if you put it on?
It looks like some kind of IR interface, I found someone who was keen to knowing that too, but didn't got any answers.

Have a nice evening!

Tim
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Buy/Sell/Wanted / Re: WARNING: eBay UK - Keithley 2100
« Last post by bitseeker on Today at 08:38:58 AM »
Leo,

Go to Advanced Search, then scroll down to the Sellers section. There, you can filter the search to include or exclude particular sellers.
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Metrology / Re: How to check how bad a suspect 720A is?
« Last post by MisterDiodes on Today at 08:37:34 AM »
Perdix,
As long as you can null out all the pots, you're unit -should- be back to operating condition and in calibration accurate to +-0.1ppm.  Unable to null S2 is a common drift problem but if that even gets to within 5uV of null you've got it very close to dialed in.  You should get a realistic sanity check on your 3458a - just keep your 3458a locked in to 10V range (if you're testing your 720a by dividing a 732a/b) and remember that any error you see will be relative to 10V - or whatever your input voltage is.  The left 3 dials will be most important, the other 4 are usually close to perfect anyway if the switches are clean - unless the unit has been overloaded.  Remember you are checking for a divided ratio out of the 720a, so keep cross-checking your 3458a between the 720a actual input vs. actual output.  Low thermals are a must here also.

Also check extended settings such as 0.5000000 vs 0.499999X - They should be very close.

The problem with sending a 720a back to Fluke for repair is hardly anyone at Fluke knows how to repair one of these.  Not efficiently anyway.  They tend to drop in whole switch assemblies when a single resistor might have drifted.

Anyway, good luck!.  These are a fantastic tool to own if you're interested in real accuracy.  If you get it to complete the calibration procedure you've just saved yourself $46,255 over the cost of a new unit.  So it pays to spend some time going through the cal sequence carefully and completely - and keep it in tip-top condition.
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Only you can say if you really need a ring to minimise the effects of surface leakage. It will depend a lot on your application, and how much there is to leak across the surface of your board. However, you broke the ring. You are trying to stop leakage across the layer the pins are bonded to. You need a continuous ring on that layer to be effective. Keep the ring continuous on the red layer and use vias to route the other signal through the blue layer.
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Buy/Sell/Wanted / Re: WARNING: eBay UK - Keithley 2100
« Last post by Leo Bodnar on Today at 08:34:54 AM »
He's short-circuiting the Internet.  Every time I search for something on eBay I have to build a huge exclusion search "stuff -crap -rubbish -junk" to cut through ware he flogs.  If anybody has a known way of excluding search result by seller name please speak up.
Quote
top-quality-tools is my favourite pet peeve
What's the problem with him?
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I'm sorry I meant I wired the two in series to make it 24V.

It's lighting up a 3d printer and this PCB is on a custom bracket on the printhead (Extruder) and I don't have a bunch of space.  I could add some type of current regulator but it'd have to be near the power supply.  I did play w/ resistors but I'm still learning and not exactly sure what I'm doing but they were getting hot so I was clearly doing something wrong.  I've been going through calculators and trying to understand what I"m doing and why it's having the effect it is but it's taking me some time.  I am more of a hands on learner and really learn by doing and noting results to be honest.  I did check the PCB again and this what I came up with (See attached pic).   It's an 8x6 array of LEDS, the left 16 (left 2 rows) share the same ground and the right 16 share (right two rows) the same hot.  THen the middle 16 are in series.  Would this be a 3P?  This is what I think it is but I'm not even remotely confident in that answer.  Or perhaps S3P3 or 1S2P?  The current draw @12Vdc is 130mA and forward voltage @12Vdc is 3.08V. 

I'm also trying to find out how/why the 8.25ohm resistors work in this circuit, it just doesn't make sense to me.

Thanks again,

Dave
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Repair / Re: Keithley 2000 Firmware Update
« Last post by Inverted18650 on Today at 08:33:04 AM »
I have spare already programmed laying around, PM me.

Thank you so much for the offer, but I already placed the eBay order. The offer is extremely kind of you.

edit: I JUST realized you are saying you have a spare chip that is already programmed, not a "spare programmer"...I will PM you in a moment. I read it too fast and misread what you were saying..
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