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nop head
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Beware fake wire!
I bought some test leads with banana plugs and alligator clips for £0.99 on Ebay from Hong Kong. They were described as "Alligator Probe Test Leads Clip Pin to Banana Plug Cable for Digital Multimeter GF". I don't know what the GF means. Very cheap and what...
I bought some test leads with banana plugs and alligator clips for £0.99 on Ebay from Hong Kong. They were described as "Alligator Probe Test Leads Clip Pin to Banana Plug Cable for Digital Multimeter GF". I don't know what t...
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Neil Darlow's profile photoKenneth Cummings's profile photoJan Ciger's profile photo
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+Neil Darlow +nop head 
Actually the quality is still there - but you must not buy the cheapest "eBay specials" you find for £0.99 ...

If you want good quality leads, I can recommend Franky's store:
http://stores.ebay.com/99centhobbies

http://www.ebay.com/itm/Silicone-Leads-with-Solid-Copper-Crocodile-Clips-and-Banana-Plugs-1-Pair-/171186982249

http://www.ebay.com/itm/50cm-20-Silicone-Test-Leads-with-Banana-Plugs-1-Pair-Yellow-Green-/201028439321

He is well known from the EEVBlog's forums and sells good quality items, with quick shipping.

Otherwise, I have never bought test leads myself, except for things like oscilloscope or multimeter probes. I always make my own.
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nop head

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Elektor 500ppm LCR meter case tips
I recently bought a 500ppm LCR meter from Elektor because I didn't have anything for measuring inductors or the ESR (equivalent series resistance) of capacitors, both of which are important for modern electronics, particularly switch mode regulators that ha...
I recently bought a 500ppm LCR meter from Elektor because I didn't have anything for measuring inductors or the ESR (equivalent series resistance) of capacitors, both of which are important for modern electronics, particularl...
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Stephanie S's profile photonop head's profile photoJan Ciger's profile photo
3 comments
 
+nop head Well, considering the price of that Elektor meter, I would say that this is an epic fail from Elektor and a very poorly designed piece of kit. At the very least I would expect the USB interface to be isolated, otherwise the PC noise and ground loops are going to swamp whatever you are measuring - as you have discovered.

BTW, you should clean off the flux residue that is visible on the boards. I think that that board is just the display and there isn't anything analog on it, but there shouldn't be flux left on boards in this grade of instrument as a matter of course.

For the price I have seen this thing sold for you can have a decent brandname meter - e.g. one of those very popular Peaktech/Atlas analysers. The accuracy and resolution are comparable and no hacking is required. Or even a second hand Agilent, if you really need a very good quality meter.

I have got a cheap Chinese LCR for about $30 which is good enough for my radio stuff. Realistically, how often do you need to measure contact capacitance or use 0.1pF resolution? Seeing the construction and the sort of hacks you had to do, I would have difficulties trusting the accuracy of the measurement of that Elektor anyway - those parasitcs measurements are really fiddly and just looking at the clips wrong can easily produce more than 100% error.

Re switching PSU issues where  you need to measure ESR - there you don't really need that much accuracy. Most often you need to only check that the ESR is within the expected range, i.e. that the cap didn't dry out thanks to high ripple current passing through it and its ESR is now too high for the circuit to function correctly.

There a specialised,  two wire ESR meter is much more practical than a general purpose LCR meter, because you can measure the caps in-circuit. Again a $20-30 on eBay and you are set. The added advantage is that when (not if) you manage to "measure" a charged cap with it, you didn't blow up a $300+ instrument ...

BTW, the Mendel90 I have got from you is still going strong, thanks a lot for that!
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nop head

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Added CraftWare to the list of slicers that can't slice my fan duct. Any others I should try?


This version of the Mendel90 fan duct that accommodates the E3D V6 hot end happens to be a shape that is surprisingly difficult for slicers. It is because of the shallow sloping slanted bridge. Skeinforge I slice everythin...
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Quentin Harley's profile photoBrent Crosby's profile photonop head's profile photo
7 comments
 
I haven't tried any other orientation because this the only one that does not need support material. The long side at the back of the photo isn't flat although from that perspective it looks like it could be. Laying on the back edge the output loop would be about 20mm off the bed.

Also any other orientation has the cylindrical parts on their side. The open end of the inner cylinder is in mid air so would be impossible to print without support.
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nop head

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Telequipment D32 trace rotation fix
Another ancient piece of equipment I have is this Telequipment D32 mains / battery operated portable oscilloscope. Telequipment is an old brand name used by Tektronix in Europe. I think it was made in about 1972 for servicing TVs. I bought it in a broken st...
Another ancient piece of equipment I have is this Telequipment D32 mains / battery operated portable oscilloscope. Telequipment is an old brand name used by Tektronix in Europe. I think it was made in about 1972 for servici...
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nop head's profile photoAshley Webster's profile photo
3 comments
 
I like them all. But definitely excited to see where your R&D goes next now that you're free from the sweat shop.
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nop head

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Ultra Low Dropout Regulator for flicker free LEDs
Cheap 12V LED lighting strips are very sensitive to small voltage changes. This is because they just have multiples of three white LEDs in series plus a small resistor to set the current. The voltage across the LEDs is more or less constant at 3 × 3.2V, so ...
Cheap 12V LED lighting strips are very sensitive to small voltage changes. This is because they just have multiples of three white LEDs in series plus a small resistor to set the current. The voltage across the LEDs is more o...
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nop head

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End Game
Since my last post there have been many expressions of sadness in the comments here and here . I'd be lucky to get so much mourning at my funeral I think! Yes it may be sad for potential customers that missed out, but not for us. Fortunately we are at a sta...
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Roger Kolasinski's profile photoGina Häußge's profile photoGary Tolley - Grogyan's profile photoMutley3D's profile photo
5 comments
 
One door closes, another will open. And no doubt a legacy will live on.
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Beware of cheap Kelvin clip LCR meter test leads
When I first got my Elektor LCR meter I didn't have any four wire test leads for it so I made up a pair from the ends of an old VGA monitor cable and some miniature crocodile clips. These worked well enough for measuring normal components but they are not t...
When I first got my Elektor LCR meter I didn't have any four wire test leads for it so I made up a pair from the ends of an old VGA monitor cable and some miniature crocodile clips. These worked well enough for measuring no...
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nop head's profile photoStephanie S's profile photoCamerin hahn's profile photoTony Olivo's profile photo
8 comments
 
Seconded on BK. I started buying their DMMs instead of Fluke (blasphemy!)
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nop head

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Cool maps
The aim of making the instrument described in the last post was to be able to quantify the cooling effectiveness of various fan and duct combinations by sampling the airflow at a grid of positions around the nozzle. I attached the denuded bulb to the termin...
The aim of making the instrument described in the last post was to be able to quantify the cooling effectiveness of various fan and duct combinations by sampling the airflow at a grid of positions around the nozzle. I attache...
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Øystein Krog's profile photoNeil Darlow's profile photo
2 comments
 
Interesting results which have borne out something I observed since fitting the Gelid fan.

I noticed that I was able to reduce my printing temperature a little. This might be attributed to the original fan applying a little cooling to the nozzle from the front-right which the Gelid does not.

Anyway. You now have a tool to investigate and optimize future duct designs in an effort to get it "more right".

Well done!
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nop head

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Quantifying cooling
A few months ago Neil Darlow mentioned that he had replaced his Mendel90 fan with a quiet version and it seemed to give better cooling results. This made me curious because quieter fans of the same dimensions generally spin slower and produce less airflow. ...
A few months ago Neil Darlow mentioned that he had replaced his Mendel90 fan with a quiet version and it seemed to give better cooling results. This made me curious because quieter fans of the same dimensions generally spin s...
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paul wallich's profile photo
 
Don't keep us in suspense!
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nop head

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A bridge too far
This version of the Mendel90 fan duct that accommodates the E3D V6 hot end happens to be a shape that is surprisingly difficult for slicers. It is because of the shallow sloping slanted bridge. Skeinforge I slice everything I print with Skeinforge, so the n...
This version of the Mendel90 fan duct that accommodates the E3D V6 hot end happens to be a shape that is surprisingly difficult for slicers. It is because of the shallow sloping slanted bridge. Skeinforge I slice everythin...
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Camerin hahn's profile photopaul wallich's profile photoDaid Braam's profile photoJeremie Francois's profile photo
5 comments
 
+Daid Braam sorry I though you knew each other. I think the object is interesting as a problematic case for slicers, which would prove beneficial to many other when the issue is solved. How to best print this particular fan shroud is certainly secondary, and  not why I cc'ed you ;)
Understanding there are some who still use Skeinforge was a surprise to me also, but as long as the tool does its job and one is happy with it... Nophead gives nice points of comparison for the silcers' programmers.
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nop head

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Tektronix 8560 still going strong
And now for something completely different... I
have been tidying my lab post kit production to make room for future
experiments. In the process I have been skipping loads of junk. I do
have trouble throwing things away that work just as well as when the...
And now for something completely different... I have been tidying my lab post kit production to make room for future experiments. In the process I have been skipping loads of junk. I do have trouble throwing things away that ...
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Mendel90 GitHub catch up
I finally found time to update GitHub with some Mendel90 changes that I have had in the works for a long time. The problem with releasing them sooner was that they were all not quite finished and / or would make unintended knock on changes to the kits I was...
I finally found time to update GitHub with some Mendel90 changes that I have had in the works for a long time. The problem with releasing them sooner was that they were all not quite finished and / or would make unintended kn...
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