hybridfree/eevblog-posts huggingface dataset:
Bench PSU output not floating for AC - Page 1
Forum section: electronics / general

author: Rolo
author_rank: Regular Contributor
timestamp: April 01, 2017, 07:36:07 am
content: I have a Delta powersupply on my bench that I use for all my projects. It has two caps (10nF and 100nF) from minus out to ground.See attached section of schematic. With this configuration the PSU output is not really floating for AC.I was measuring with my scope on a VFD filament driver that switches at 100 KHz, the wave was distorted, because the AC found the path to ground via the scope probe.Trough these caps I assume. The circuit was not connected to USB or other devices. I did see Dave's tutorial on grounds and scope measurements.So what's the function of these caps and does every PSU has (or need) them ?Should a bench PSU not be really floating to avoid these issues ?

author: David Hess
author_rank: Super Contributor
timestamp: April 01, 2017, 11:49:50 am
content: If it is a switching power supply, then those might be included for noise filtering. My floating bench supplies include no capacitors from the outputs to ground.Even without capacitors to ground, the common mode capacitance will be 10s to 100s of picofarads through proximity of the circuits and the transformer. Special "high isolation" designs are used to lower this.

author: Rolo
author_rank: Regular Contributor
timestamp: April 01, 2017, 11:55:09 am
content: It's linear with thyristor pre-regulation. 30V/3A.Verstuurd vanaf mijn ONEPLUS A3003 met Tapatalk

author: Rolo
author_rank: Regular Contributor
timestamp: April 01, 2017, 01:58:10 pm
content: This is the CUT (Circuit Under Test)This is the measument using the Delta PSU with caps :This is the measument using a 5V floating PSU :For me the Vrms value was important and you can see that there is a big difference in the results.

author: Ian.M
author_rank: Super Contributor
timestamp: April 01, 2017, 02:08:52 pm
content: No one experienced expects a bench supply to be fully floating at higher frequencies. Fully floating, low capacitance isolated supplies are $EXPENSIVE$ and typically lack many of the features one expects from a bench supply.You should have used a differential probe, or a 'poor man's differential probe'(waveform arithmetic, Y1-Y2 using identical probes, with Y2 gain and compensation trimmed with both probes on the 'hot' switching node to null out the common mode error as much as possible), or temporarily moved the center tap ground to one end of the filament or used a battery supply, with the whole circuit sat on an upturned plastic box to reduce the capacitance to ground.
Cheap DT830 DMM being zapped on live TV (in portuguese) - Page 1
Forum section: electronics / general

author: rsjsouza
author_rank: Super Contributor
timestamp: April 02, 2017, 02:38:10 am
content: This is a famous Brazilian TV host that was showing how to use a Multimeter on live TV.In all fairness, she was terribly advised by the production crew, which should have prepared her better and got a safer meter.

author: Nusa
author_rank: Super Contributor
timestamp: April 02, 2017, 02:44:47 am
content: Thou shalt not switch your meter to measure current when measuring voltage!To be fair, it didn't seem to be measuring voltage very well either, even when it was on the right scale.

author: med6753
author_rank: Super Contributor
timestamp: April 02, 2017, 04:45:26 am
content: What DMM? All I saw was.....nevermind!

author: Brumby
author_rank: Unknown
timestamp: April 02, 2017, 06:03:22 am
content: Quote from: med6753 on April 02, 2017, 04:45:26 amYeah ... that plastic parrot.

author: rsjsouza
author_rank: Super Contributor
timestamp: April 02, 2017, 10:41:35 am
content: Quote from: Nusa on April 02, 2017, 02:44:47 amYes. The outlets in Brazil are round and regular probe tips usually require some effort to properly make contact with their internal contacts.
How to cut wood without a saw  - Page 1
Forum section: electronics / general

author: grifftech
author_rank: Frequent Contributor
timestamp: April 02, 2017, 05:05:58 am
content: here is the link:https://www.youtube.com/watch?v=LqnOV5aGC6I&feature=youtu.beplease watch to the end.

author: janekm
author_rank: Unknown
timestamp: April 02, 2017, 06:05:30 am
content: An April fool's video doesn't work so well if it has April fools written all over it... That's not really the pointLook back at some of Dave's efforts from previous years, there were some good ones...

author: Red Squirrel
author_rank: Super Contributor
timestamp: April 02, 2017, 06:41:42 am
content: You should be able to use the laser from a mitre saw to cut wood without using the saw itself. Just need to put in a slightly more powerful diode in there and good to go!If you cut it too short, don't worry, just need to go grab the wood stretcher in back of the truck.
PSA: Latest iOS will nag when you post things without TLS. - Page 1
Forum section: electronics / general

author: technix
author_rank: Super Contributor
timestamp: March 31, 2017, 10:20:40 am
content: I just found this out while posting here. Tried on my blog that have mandatory TLS yielded zero nag.@EEVblog Please get mandatory TLS up ASAP.

author: Halcyon
author_rank: Unknown
timestamp: March 31, 2017, 10:29:36 am
content: The latest Apple IOS will nag you regardless. Get with the times and stop using that rubbish ;-)

author: technix
author_rank: Super Contributor
timestamp: March 31, 2017, 10:57:00 am
content: Quote from: Halcyon on March 31, 2017, 10:29:36 amI am kind of stuck there as iOS development is in my job description...
That was a quite obvious one (repair) - Page 1
Forum section: electronics / general

author: capt bullshot
author_rank: Super Contributor
timestamp: March 31, 2017, 08:16:17 am
content: The "thing" now works fine again (after replacing the electrolytic cap). The cap orignally rated 2200uF / 6.3V, I replaced it by whatever I found in the junk box (2200uF / 35V).Bonus points for everyone who recognizes the "thing"

author: mauroh
author_rank: Frequent Contributor
timestamp: March 31, 2017, 09:30:31 am
content: Without googling I'd say its a Tecktronics Oscilloscope, should be a TDS220 or a very similar oneMauro
Who knew what these forum icons signify? - Page 1
Forum section: electronics / general

author: wilfred
author_rank: Super Contributor
timestamp: March 31, 2017, 04:36:50 am
content: /.

author: EEVblog
author_rank: Unknown
timestamp: March 31, 2017, 04:41:33 am
content: I can remember the thread when the idea was proposed and someone made the images. We all thought it was cool.
Only in Australia - Page 1
Forum section: electronics / general

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 30, 2017, 09:54:01 am
content: http://www.abc.net.au/news/2017-03-30/bull-shark-found-washed-up-near-ayr/8401872

author: Brumby
author_rank: Unknown
timestamp: March 30, 2017, 11:12:55 am
content: Juvenile dusky whaler shark rescued from ocean baths in Palm Beachhttp://www.smh.com.au/environment/animals/juvenile-dusky-whaler-shark-rescued-from-ocean-baths-in-palm-beach-20170328-gv8j0q.html

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 30, 2017, 11:55:53 am
content: This one is scary.http://www.theage.com.au/victoria/big-mother-of-a-snake-photobombs-mums-snap-of-twoyearold-daughter-20170330-gv9n1v.html

author: rt
author_rank: Regular Contributor
timestamp: March 30, 2017, 01:13:24 pm
content: Chris Gammell doesn't stand a chance really between these and the drop bears ....

author: calexanian
author_rank: Super Contributor
timestamp: March 30, 2017, 11:26:21 pm
content: Quote from: rt on March 30, 2017, 01:13:24 pmHe will be fine. We sent a whole roll of bubble wrap with him.
Eevblog youtube - Page 1
Forum section: electronics / general

author: Daxxin
author_rank: Regular Contributor
timestamp: March 30, 2017, 05:45:08 am
content: What camera model is using Dave to record video for youtube? Very clear view of pcb even very closed.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 30, 2017, 07:01:31 am
content: I don't remember the models, but he uses several cameras. Look at some of his old mail bags because he says the models in those videos.

author: EEVblog
author_rank: Unknown
timestamp: March 30, 2017, 07:01:48 am
content: Canon HF G30Opteka x10 macro lens for closeups.
How do you comment to a moderator about a thread that was locked? - Page 1
Forum section: electronics / general

author: wilfred
author_rank: Super Contributor
timestamp: March 29, 2017, 09:52:51 pm
content: /.

author: IanB
author_rank: Super Contributor
timestamp: March 29, 2017, 09:57:50 pm
content: There is a separate thread somewhere for discussion of moderator actions. You could ask the question there.However, the particular thread in question was going round in circles and converging nowhere. There was no point in letting it continue and pollute the board since it was way off topic and convergence was unlikely at best.Since the common advice of "don't argue with fools" was not being followed, what was a moderator to do?Edit: This is the thread I was thinking of:https://www.eevblog.com/forum/chat/moderation-reports/

author: lowimpedance
author_rank: Super Contributor
timestamp: March 29, 2017, 10:50:18 pm
content: Quote from: IanB on March 29, 2017, 09:57:50 pmExcept that thread is also locked
Expression for Ripple factor in Inverse Chebyshev  - Page 1
Forum section: electronics / general

author: MrOmnos
author_rank: Frequent Contributor
timestamp: March 29, 2017, 08:27:20 pm
content: When normalizing a inverse Chebyshev is it the Pass band cutoff frequencywpset to 1rad/s or is it stop bandwsfrequency set to 1 rad/s?I derived the following expression for the ripple factorEby normalizingwp= 1.But the expression different in text book. It seems they have setwsfrequency set to 1 rad/s and used expression for minimum attenuation at stop band to derive the equation. Hence, they have a different expression where they havealphaminin their expression. What am I missing here? Why did they do that?

author: MrOmnos
author_rank: Frequent Contributor
timestamp: March 29, 2017, 09:46:55 pm
content: Ahh I get now!!
BRAND NEW IBM AT 5170 from 1988 unboxing  - Page 1
Forum section: electronics / general

author: knks
author_rank: Regular Contributor
timestamp: March 28, 2017, 10:21:58 pm
content: Guy bought a brand new IBM PC made in 1988

author: JoeN
author_rank: Frequent Contributor
timestamp: March 28, 2017, 11:59:36 pm
content: He had quite a few to sell. Last listing ended yesterday, he may be relisting or just out.http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=IBM%20AT%205170%20new&LH_Complete=1&rt=ncWas asking $500 and lots of people paid it.

author: james_s
author_rank: Super Contributor
timestamp: March 29, 2017, 12:12:15 am
content: That's a really amazing find. I'm actually kind of glad they all sold before I saw that, I'd have been tempted to get one but I already have too many old computers.

author: knks
author_rank: Regular Contributor
timestamp: March 29, 2017, 01:31:39 am
content: I would definitely pay if I was in US

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: March 29, 2017, 09:00:40 am
content: Funny to see the computer I used when I first started working listed as "vintage". It seems that the demand for obsolete/vintage computers is not that great, several items on 15% offhttp://www.ebay.com/itm/Rare-Working-IBM-5170-AT-Computer-Keyboard-in-Original-Box-ships-worldwide-/192130912948

author: james_s
author_rank: Super Contributor
timestamp: March 29, 2017, 03:29:27 pm
content: Well they're asking over $1,000, which is top dollar and then some. Demand is there but there but that doesn't mean it's worth *that* much.
Ground yourself - Page 1
Forum section: electronics / general

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 27, 2017, 09:16:03 am
content: Hehe, thanks!Here's a nice front panel grounding upgrade I found on a machine tonight in return.

author: MagicSmoker
author_rank: Super Contributor
timestamp: March 27, 2017, 11:40:37 am
content: Best travel tip I've read yet! That comment needs more likes!

author: Vtile
author_rank: Super Contributor
timestamp: March 28, 2017, 12:32:13 am
content: *BleeB* *BleeB*Officer : What is that metal wire you are dragging along to the plane?The passenger: It is my grounding wire.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 28, 2017, 12:36:39 am
content: ...

author: dakiller
author_rank: Contributor
timestamp: March 28, 2017, 01:51:27 am
content: Just carry a bucked of ground with you.

author: BradC
author_rank: Super Contributor
timestamp: March 28, 2017, 01:54:17 am
content: Quote from: dakiller on March 28, 2017, 01:51:27 amNow that's a down to earth solution.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 29, 2017, 02:45:48 am
content: Quote from: dakiller on March 28, 2017, 01:51:27 amI wonder if that is technically legal. "a ground rod shall be inserted into the soil". Well, a ground rod is inserted to soil.

author: Brumby
author_rank: Unknown
timestamp: March 29, 2017, 04:22:47 am
content: There could be a rather interesting legal argument if there is not formal definition for the term "the soil" - and it would all be hinging on the word "the".Try that here in Australia and you might find a judge saying something equivalent to "Stop being a dickhead". Well, that's what it might have been like 40 years ago. These days, I'm not so sure any more.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 29, 2017, 05:59:06 am
content: Yeah always someone looking for a loophole.Seriously though I wonder what is even the reasoning behind what they did, I sure hope it's just a joke. They probably could have used that railing as a ground. Maybe need to ground it to a real ground elsewhere but for a temporary thing it would be much better than trying to be a smart ass haha.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2017, 08:22:45 am
content: I'm sure regulations added contact resistance with the ground as a requirement, or possibly that the rod has to be xx deep into the soil.Some people take things literally.
Stepper Drivers (Salvaged MFP) - Page 1
Forum section: electronics / general

author: metrologist
author_rank: Super Contributor
timestamp: February 10, 2017, 08:44:10 pm
content: Since I resolved the issues I was having with my Brother MFP I have discovered some stepper motors. I have some stepper motor drivers that are missing and I do not recall what they were, so am looking for something inexpensive from a noteworthy ebay seller. If someone could help advise.One motor looks like a NEMA 17 size and the others are smaller. I have not gotten into the base yet, but I think there is one or two more that will be OK size. I will also post up the circuits I am getting because there might be drivers already there I can use, although they are looking a bit integrated so far.Anyway, I still want to pick up a few more good stepper drivers, may around a couple amps for the smaller stepper motors like these. I think they were a couple bucks. Thanks

author: metrologist
author_rank: Super Contributor
timestamp: February 13, 2017, 08:28:25 pm
content: The chips I thought would be drivers are labeled SHENDEGEN with some numbers. I cannot find a datasheet for any of them, but one was identified as an ethernet controller. Maybe they are being used for drivers anyway.I think I found what I wanted anyways, DRV8825. What I bought before was A4988.

author: metrologist
author_rank: Super Contributor
timestamp: March 27, 2017, 04:04:44 pm
content: I got the DRV8825 drivers in and set up a simple Arduino program that I've used before, which just varies the speed up and down.I tried the small stepper labeled 4.9 ohm and I am using a 9V supply for the motor. This motor is about 40mm diameter and 15mm thick. The motor does not run at low speed, but does spin smooth within a certain narrow RPM range. I cannot get it to single step - the shaft twitches hard but does not rotate, and there is a lot of torque. And the motor gets very hot.Any ideas what I need to change?

author: metrologist
author_rank: Super Contributor
timestamp: March 28, 2017, 05:08:26 am
content: I think its this 12v motor.http://www.mitsumi.co.jp/latest/Catalog/pdf/motor_m42sp_6nk_e.pdfI am sending a pulse with arduino and the motor does not move until 1us pulse

author: metrologist
author_rank: Super Contributor
timestamp: March 28, 2017, 03:41:42 pm
content: OK, there is a little pot on the driver board that is very sensitive to position. That pot is supposed to just be a current limiter as far as I know, and I recall reading a procedure to measure voltage on some pin and adjust to the voltage for the desired load. I put drag on the motor and adjusted the pot for max torque, which was more like just finding the spot that would make the motor turn.Now the motor does not get so hot and it turns, up to 6k pps.
An EEVblog BM235 Multimeter for $117.34 USD including shipping to Texas! WOW - Page 1
Forum section: electronics / general

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 28, 2017, 01:52:30 pm
content: An EEVblog BM235 Multimeter for $117.34 USD including shipping to Texas! WOW!!Thanks Dave for the discount!
Problems about my LM95071 - Page 1
Forum section: electronics / general

author: Shoo
author_rank: Newbie
timestamp: March 28, 2017, 09:23:11 am
content: Hello, I hope this is the suitable place to ask .I have worried a few days.I am using the LM95071 in a simple application to measure ambient temperature of our product. The normal temperature range is approx 15degC through to 50degC. In general the part is working well, however intermittently I will read a value of -22degC. The spurious values occur around once every 100-200k reads.Typically a valid read should be 0x0eab, however I am occasionally getting spurious values of 0x0f4b3, 0x0f4a7, 0x0f4a3 or 0x0f4b7I am reading the LM95071 every 4ms, which is much faster than its conversion time, however the datasheet implies that this should not be a problem as the read doesn't inhibit the conversion process and the temperature register is updated when /CS is high after the conversion is complete. Is it possible that the asynchronous nature of the SPI transactions is causing a problem with the chip or is there another explanation for these spurious and incorrect readings?I have attached a scope trace of the offending read. My observation of the trace is that the SPI timing and transaction look fine, expect the data coming out of the LM95071 is incorrect given the actual temperature. Note: /CS is Yellow, MISO is blue, CLK is green and our trigger output is pink.Can you help with information or suggestions as to what the problem may be?We haven't tried slowing it down yet, however in a effort to try and get more occurences we did speed up the reads and have an image that reads a value every 300us. This does in fact produce more frequent errors and in fact we have found that it is not just a single bad read, but a burst of values that are around the 0xf4b3 point.What happens at the 130ms point in the LM95071 converter? Can you provide more info as to what might be happening?We can try reading no greater than once every 130ms however based on the rate of occurances to date that might be a month in between failures and therefore harder to debug.However, regarding the operation of the device from thedatasheet, I see that the typical conversion time is 130ms (228ms max) and the note that goes with that states:QuoteI had interpreted that as having the ability for us to read the output of the LM95071 at any time and at any rate with the only penalty for this being that we would get the same answer multiple times. It would appear that if we read the part too soon after a conversion has completed that we can get the invalid outputs.What worries me is that if this is a purely asynchronous process then even if we do read at 130ms or greater then we may still have an issue if we read too soon after the completion of a transaction. If this is true then it appears the only way to solve the problem is to do multiple reads and throw out any suspect readings.All the suggestions and every suggestion will be grateful.Regards,Shoo
TENV Motor Internal Fan: Required?  - Page 1
Forum section: electronics / general

author: jpanhalt
author_rank: Super Contributor
timestamp: March 27, 2017, 05:07:18 pm
content: I have a TENV fractional HP (1/6 HP) Leeson motor on a septic aerator. The bearings froze and are shot after just 2 years. The armature has a plastic internal fan that makes removal of the armature and replacement of the end bearing difficult. There is no external capacitor. The fan can probably be removed with a little heat, but I am worried about getting it reattached well. Of course, I would use Loctite if I get to that point.Question: Is the fan really necessary?John

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 27, 2017, 05:35:25 pm
content: TENV - Totally Enclosed Non-Ventilated (for the young players out there)IMHO, no, you could leave it off for all pracitcal purposes.

author: Benta
author_rank: Super Contributor
timestamp: March 27, 2017, 06:32:34 pm
content: Quote from: tpowell1830 on March 27, 2017, 05:35:25 pmI disagree. Noone puts a fan there without a reason.Note that the fan is internal, and probably serves to eliminate local hot areas by circulating air within the motor.Externally, the motor is TENV, but that's another issue.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 27, 2017, 07:55:33 pm
content: SOLVEDI as able to get the fan off without heat or damage. Will re-install with a little Loctite. I would rather re-assemble as built. My fear was that if the fan got damaged in the process, it is not a part I can buy retail.Thanks all for the advice.John
Action camera what is this port used for  - Page 1
Forum section: electronics / general

author: sony mavica
author_rank: Frequent Contributor
timestamp: March 31, 2017, 02:03:18 am
content: just found my cheap $15 action camera i thought i had lost for good went to charge it and noticed this port under the usb port anybody know what its used for?

author: Brumby
author_rank: Unknown
timestamp: March 31, 2017, 02:12:17 am
content: Possibly a micro HDMI port. Size and shape seem about right.How many contacts can you see on the tongue in the middle?
Audio mixer for sale - Page 1
Forum section: electronics / general

author: R_Gtx
author_rank: Regular Contributor
timestamp: March 03, 2017, 08:51:19 pm
content: Vintage EMI TG12345 MK IV recording console for sale, only two careful owners:http://www.bonhams.com/auctions/23878/lot/35/No price estimate given! So you would probably have to remortgage the house!

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 04, 2017, 08:27:59 am
content: That would actually match the decor at my church, I need to see if I can get them to buy it.

author: R_Gtx
author_rank: Regular Contributor
timestamp: March 27, 2017, 07:19:51 pm
content: Sold for US$ 1,807,500 (£1,434,231) inc. premium.
Transistor Full Documentary - Page 1
Forum section: electronics / general

author: MK14
author_rank: Super Contributor
timestamp: March 27, 2017, 12:48:36 am
content: I already watched it, probably because of THIS thread:https://www.eevblog.com/forum/chat/transistor-full-documentary/msg1114081/#msg1114081

author: xrunner
author_rank: Super Contributor
timestamp: March 27, 2017, 12:51:24 am
content: Quote from: MK14 on March 27, 2017, 12:48:36 amYea - beat you to it this time Homer!

author: MK14
author_rank: Super Contributor
timestamp: March 27, 2017, 12:53:59 am
content: But anyway, I REALLY! enjoyed watching that video a while ago. It was VERY interesting.
Wire manufacturing 1960's - Page 1
Forum section: electronics / general

author: edavid
author_rank: Super Contributor
timestamp: March 26, 2017, 04:26:57 pm
content: Why do you post every video you find in a separate thread? Wouldn't a single thread work just as well?

author: timb
author_rank: Super Contributor
timestamp: March 26, 2017, 04:34:12 pm
content: Quote from: edavid on March 26, 2017, 04:26:57 pmI think separate threads are more interesting, as it sparks fairly long posts about a particular subject (like the IBM PC AT unboxing video).It's also much more likely to catch people's attention, since the title is about the video in question and not generic.Essentially, it's fine.

author: rrinker
author_rank: Super Contributor
timestamp: March 26, 2017, 04:45:29 pm
content: Yes, and it sparks conversation about a single topic rather than a huge mashup. Witness the IBM PC-AT one.Carry on.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 26, 2017, 06:32:59 pm
content: Once toured a local-ish drawing plant (thought it was Sussex Wire, but it doesn't look like they're in the business of wire anymore?), lots of machinery and lots of copper flying about.Tim

author: SeanB
author_rank: Super Contributor
timestamp: March 26, 2017, 06:37:05 pm
content: And this is why most Telco's are trying to get rid of the copper in the ground, as it is so expensive to maintain, with the drive they have to have zero trained staff. Going to be hard to outsource the cable crews, the equipment and such when it all has to be pretty much local to the customer base, you have a required service level for POTS ( and not a "best effort" either) that is legislated and has some rather severe penalties built into it.

author: xrunner
author_rank: Super Contributor
timestamp: March 26, 2017, 06:54:09 pm
content: Yea and those men working there back in the day probably were able to support a household with a wife at home and several kids, had a good salary, a pension, and looked forward to the kid getting a job at the plant too. Boy those days are long gone.
Apollo Artifact Comes Out of Storage at the Smithsonian - Page 1
Forum section: electronics / general

author: SeanB
author_rank: Super Contributor
timestamp: March 26, 2017, 05:36:49 pm
content: When I was young I went to the museum, and there had a touch ( likely along with millions of others) of lunar rock, on public display in an exhibit on show at the time.Thanks Homer, remember the museum a little, and riding in a City of Johannesburg double decker bus, must have been in the 1970's, and before the release of Star Wars.....
uCurrent (GOLD) maximum current question - Page 1
Forum section: electronics / general

author: mrTheWheel
author_rank: Newbie
timestamp: March 27, 2017, 01:46:05 am
content: Hi,I wonder if the uCurrent has a maximum allowed current to pass thru?Somewhere in the documentation I find "The maximum current in the mA range is a nominal 300mA, as this is the contact rating of the switch. But in practice it can be higher than this." but I have no idea if this is the maximum that can be measured or the maximum before it will blow up the uCurrent.I intent to use the uCurrent to measure the total power used of a micro controller during a complete cycle of wake/powering up, doing stuff and going to (deep) sleep.The device can draw as much as 400mA - 800mA during operation and some uA during deep sleep. Of course I understand I can only use the uCurrent to measure the low currents but it is unpractical (if not impossible) to take the uCurrent out of the equation during the high power consumption.Thanks in advance for any help on this!

author: alm
author_rank: Super Contributor
timestamp: March 27, 2017, 11:21:39 am
content: According to theµCurrent Gold project page, the maximum current on the highest range is 1250 mA, and could be further increased by feeding it a higher battery voltage. No mention of the 300 mA limit there, but to be safe, you could avoid switching current ranges while the device is operating.

author: MLXXXp
author_rank: Frequent Contributor
timestamp: March 27, 2017, 07:08:26 pm
content: https://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg375819/#msg375819
New Electronic Thermometer, 1955 - Page 1
Forum section: electronics / general

author: SeanB
author_rank: Super Contributor
timestamp: March 26, 2017, 03:58:24 pm
content: Now available for under $5 as well, and it is hard now to actually buy a mercury thermometer as well.

author: Stupid Beard
author_rank: Regular Contributor
timestamp: March 26, 2017, 03:59:16 pm
content: I like how they say it can be used in the dark, which skips over the fact that to actually use it in the dark you'd still need a light and thus could use any thermometer

author: Brumby
author_rank: Unknown
timestamp: March 26, 2017, 04:25:12 pm
content: Quote from: SeanB on March 26, 2017, 03:58:24 pmI still remember the first time I saw a mercury thermometer. A nice long one in high school. The teacher was going to show us the temperature changes from ice to steam, so she put ice in a flask, took a cork and put a hole in it, fitted this onto the flask and then inserted the thermometer into the hole. After a little entertainment where she lit the gas tap instead of the bunsen burner, we had heat under the flask.The ice melted, the temperature rose and when it started boiling I didn't notice any steam escaping - that was until the cork and thermometer were launched into the vermiculite ceiling. (The cork survived.)An electronic thermometer wouldn't have been half as much fun.
Looks like interesting repair challenge. - Page 1
Forum section: electronics / general

author: Dataforensics
author_rank: Unknown
timestamp: March 25, 2017, 02:37:33 pm
content: http://www.ebay.co.uk/itm/Keithley-2000-Digital-Multimeter-/182495577197?hash=item2a7d95846d:g:YXMAAOSwuxFYztUATony

author: martinator
author_rank: Contributor
timestamp: March 25, 2017, 02:56:36 pm
content: I bet it smells nice.

author: Yansi
author_rank: Super Contributor
timestamp: March 25, 2017, 03:06:33 pm
content: It is no challenge, if you can't buy it to fix it. UK hates Europe. Doh!

author: Ampera
author_rank: Super Contributor
timestamp: March 25, 2017, 03:38:43 pm
content: Quote from: Yansi on March 25, 2017, 03:06:33 pmWhy are you complaining? After the UK leaves the EU, they won't be taking a good portion of their GDP with them.Now off the topic of politics which I shouldn't even be talking about."Interesting" is a word that CAN be used to describe the task needing to be undertook to return that machine to working order.Insane is also another word, but if you think it's worth it, go for it.

author: German_EE
author_rank: Super Contributor
timestamp: March 25, 2017, 03:46:00 pm
content: Give me a schematic and a copy of the PCB layout around U131 and I'll have a go. I wonder why he only wants to post to the UK though because sending parcels anywhere inside the EU is a no brainer.

author: Yansi
author_rank: Super Contributor
timestamp: March 25, 2017, 03:51:18 pm
content: Thinking the same, German_EE. Just your neighbour.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 25, 2017, 04:00:08 pm
content: Frrom the schematics U131 is an LM339, used to drive JFETs from input switching. So the good thing is this part does not need to be low leakage, but chances are high that there are also some of the JFETs broken - worst case the CPLD is gone too.

author: Dataforensics
author_rank: Unknown
timestamp: March 25, 2017, 04:01:20 pm
content: Sorry, looks like this auction is already being discussed, must remember to run searches on the forum.

author: apelly
author_rank: Unknown
timestamp: March 25, 2017, 11:46:30 pm
content: Quote

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 26, 2017, 03:08:56 am
content: Just needs a little IPA and it will be good as new
Core of Inductor - Page 1
Forum section: electronics / general

author: rckanta
author_rank: Contributor
timestamp: March 26, 2017, 07:17:49 am
content: How to calculate the maximum capable power rating of the core of a inductor ?I am trying to design a boost converter but I do not how to choose the core.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 26, 2017, 07:22:36 am
content: If the core is distributed gap type (such as powdered iron), it depends on the losses:https://www.seventransistorlabs.com/Articles/Core_Loss.htmlIf the core is discrete gap (usually ferrite), the gap should be set to give an effective permeability of 10-100, depending. The gap sets the inductivity (inductance per turns squared) and saturation current (amp-turns), proportionally, and independent of saturation flux (volt-seconds).Tim

author: rckanta
author_rank: Contributor
timestamp: March 26, 2017, 07:45:49 am
content: core I am choosing toroidal core
"She's gonna blow captain!" - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 25, 2017, 05:41:06 am
content: PC in the office that has the cover off (no idea why, maybe it was overheating) and the PSU fan started to grind so went over to give it a bunch of taps to make it stop, and I peaked inside and noticed those caps.Yeah, it's a Dell.

author: raspberrypi
author_rank: Frequent Contributor
timestamp: March 25, 2017, 05:43:33 am
content: Every electronic issue can be solved by replacing the caps.

author: Vgkid
author_rank: Super Contributor
timestamp: March 25, 2017, 06:37:09 am
content: It looks like that computer is well over a decade old.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 25, 2017, 06:55:18 am
content: Quote from: Vgkid on March 25, 2017, 06:37:09 amI'd say about that old. Dell Optiplex GX620 with a Pentium 4. It's a machine we use for various stuff such as remote into places that can only be accessed via dialup. It has a modem connected to it and a phone line.

author: Vgkid
author_rank: Super Contributor
timestamp: March 25, 2017, 07:19:44 am
content: Quote from: Red Squirrel on March 25, 2017, 06:55:18 amI saw some 05/05 date codes. Our only family computer until I got my laptop was a 900Mhz(initially)AMD Athlon. Eventually everything other than the mobo was upgraded.

author: Ampera
author_rank: Super Contributor
timestamp: March 25, 2017, 03:45:04 pm
content: Dell OEM systems are made to be cheap and to be replaced. Companies sign deals, and then get to replace them whenever one busts. They are expendable. Their consumer machines, however are not that far off them that design, which is one reason why mainstream prebuilts are suffering. That and the advent of smartphones and tablets.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 26, 2017, 02:00:03 am
content: Quote from: TwoOfFive on March 25, 2017, 03:45:04 pmYeah and to be fair for most purposes they run fine and last a decent time. This particular machine has been on pretty much from the moment it was put into production, is not on UPS or surge protection so has seen all sorts of surges, brownouts, hard power downs etc... it's a miracle it's even still running.What gets me though is the waste that goes into lease contracts. For our main computers they are now on a lease life cycle and get changed every couple years whether or not it's needed. Instead of replacing with something super high end and keeping it for 5-10 years like they originally did with these dells they go with bottom of the barrel and replace them often. Though I think with leases the old machines end up on "outlet" sites and such so I guess it's not a waste, but actually nice for people who want to scoop them up for cheap.
What a name for an operating system. - Page 1
Forum section: electronics / general

author: Ampera
author_rank: Super Contributor
timestamp: March 12, 2017, 02:20:38 pm
content: The name for it is Breadbox EnsembleIt's from the people who did GEOS as a DOS-based UIhttps://en.wikipedia.org/wiki/GEOS_(16-bit_operating_system)I guess someone stared at a few too many breadboxes and decided to name an operating system after it (wtf?)

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 12, 2017, 03:36:33 pm
content: "breadbox" was the nickname for the Commodore 64. GEOS started on the 64. It's probably a homage.

author: Zero999
author_rank: Super Contributor
timestamp: March 12, 2017, 06:45:19 pm
content: The link doesn't work. Here's the corrected link:https://en.wikipedia.org/wiki/GEOS_(16-bit_operating_system)It's just an alternative to Windows 3.1. It might be useful if you have a really old computer, which can't run any other graphical OS.
Silly but I suppose that is what hobbyist do - Page 1
Forum section: electronics / general

author: Rick Law
author_rank: Super Contributor
timestamp: March 30, 2017, 07:13:51 am
content: Silly to repair something that is practically worthless, I suppose that is something hobbyist do.I have this box of broken USB cables. Some were perfectly good but for retired equipment (such as the Treo). I was tired of looking at a box of junk but just didn't want to throw them out.USB cables are getting so cheap it is not worth the time, but, the silly bug hit. So, I cut the USB cables to see what I can do with them: find the bad end and install a new plug of my choice. You know, the color-coding scheme seem to be different from cable to cable! One has yellow D+ and another has red for ground!!?? Sorting them out was easy as long as the normal USB side was at least making intermittent contact.Such a time waste but now I have "new" cables2x USB -> microUSB-only charge cable for use in the cars4x USB -> microUSB charge+data cable, now I can leave some down & up stairs.2x USB -> miniUSB (for Nano) charge and data cable1x USB -> miniUSB charge only cable (for an old phone occasionally serving as a back-up/power-outage alarm clock)I can make 4 more... But I have to wait for more parts to do anything with them. I have to decide what the metamorphosis should turn them into. I think some may become USB extension cables.For the micro/mini USB plugs, it really was not worth spending $2+ for a molded connector. So, initial couple of cable was just heat shrink tubing covered over the soldered side of the new bare plug. The last few, I applied hot-glue to the newly replaced plug before cover it with heat shrink tubing so the outer cable-jacket is glued to the plug. Not pretty but works.Time included, the new cable is not worth the $. But, "not-pretty" is still darn better looking than a box of worthless junk...When silly bug hits, one has no recourse but to surrender.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: March 30, 2017, 07:36:43 am
content: Well, you are not alone. I frequently chop up USB cables to the length I need in each case.This very much reduces the "snakeiness" around the computer.I even built a simple tester with LEDs to make absolutely sure that the power linesare not polarity reversed or have been confused with the data lines.This is important as otherwise you may damage USB ports.
Mobile Firefox problems- Android - Page 1
Forum section: electronics / general

author: Vgkid
author_rank: Super Contributor
timestamp: March 10, 2017, 04:37:57 pm
content: Anyone have any pointers for gettin ff-on android to work. It was forking great until a few hours ago. Sites won't load, or if they do it takes several minutes. I have gone through and reinstalled ff, to no avail.Doesn't matter if only on mobil data,wifi, or both.

author: Vgkid
author_rank: Super Contributor
timestamp: March 11, 2017, 03:06:00 am
content: Well, it was working for a few hours, and it started glitching again.

author: Ampera
author_rank: Super Contributor
timestamp: March 12, 2017, 06:43:39 am
content: I never use Firefox on Android. I always use Chrome because on Windows or on Android, Chrome is superior in performance and compatibility to Firefox (Also their dev team apparently consists of assholes, as my dad tried to contact them with a suggested feature and they treated him like a dumbass).Web browsing on Android is always a joy. Most websites are broken, or have terrible mobile interfaces, and the rest demand you use their app when all you want to do is look at one goddamn thing.If you have to web browse, dump Firefox, try something like Dolphin or Chrome.
Random buy: a full 80C88 chipset, and a lot of SRAM. - Page 1
Forum section: electronics / general

author: technix
author_rank: Super Contributor
timestamp: March 11, 2017, 08:53:11 am
content: Today while I was hunting for the PC166 SDR SDRAM for my AT91SAM9260 project, I bought stuff compulsively:* A full set of CMOS 8088 parts in DIP package: 80C88, 82C55, 82C51, etc* 40x IS61C256 32kB 8-bit SRAM in TSSOP* 10x 74HC138 in TSSOPMaybe couple those to one of my AT28C256 EEPROM and I can get an IBM PC XT workalike up and running, with full 1MB of SRAM? The SRAM can be arranged into 4 sticks of 8 chips each, with an on-module 74HC138 as decoder.
Solder paste storage - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 10, 2017, 11:13:07 pm
content: I bought solder paste a while back, thinking it might come in handy at some point, but did not immediately need it. Went to use it and noticed it says to store in the fridge and only let it warm up to room temp when you use it. I missed that when I first bought it so it's been in the closet since. Is it bad at this point? It did not seem to work very well but never used that stuff before so maybe I was doing something wrong, too. It mostly just stays in a gooey consistency.

author: iainwhite
author_rank: Unknown
timestamp: March 10, 2017, 11:35:43 pm
content: What date did you buy it?Manufacturers seem to say 6 months is a rule of thumb for the life expectancy if it is refrigerated for all that time. I suspect if it has been at room temp for several months it is probably starting to thicken - the flux reacts with the solder and makes it more "sticky/lumpy"

author: james_s
author_rank: Super Contributor
timestamp: March 10, 2017, 11:38:29 pm
content: It's almost certainly bad from a production standpoint, but likely still usable for a hobbyist. I have some very old solder paste that I just squirt a bit out and mix in some liquid flux when I'm ready to use it.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 11, 2017, 04:03:51 am
content: Oh it's probably been like a year at least lol. It's just something I never really considered that could go bad but then I saw that notice. Whoops. It does sort of turn into solder when I solder it with my iron, but it just leaves gunk behind and the solder does not actually bond with anything. Even tried with some easy through hole stuff just to test it out. Though I don't think it's really meant to be used with an iron either, but hot air, so that could be my issue too. Or should it still work better than that with an iron?

author: D3f1ant
author_rank: Frequent Contributor
timestamp: March 11, 2017, 07:17:13 am
content: It should work as solder regardless of how heat is applied. I suspect the Flux has evaporated or deteriorated, adding a liquid Flux should bring it back to life although you might find it will leave extra residue. Residue can be removed of course. If it's only slightly to thick adding a bit of IPA does wonders.
Legends of the LASER and Negative Feedback Amplifier - Page 1
Forum section: electronics / general

author: rfeecs
author_rank: Frequent Contributor
timestamp: March 10, 2017, 05:24:45 pm
content: These two videos struck me as being quite similar. One is of Charles Townes, inventor of the MASER and the LASER. The other is of Harold Black, inventor of the negative feedback amplifier. The same negative feedback we use all the time in op-amps and put on tee shirts.Both videos are of old guys, taken shortly before their death, talking about the legendary moments of their great invention: one while sitting on a park bench, and the other while riding the ferry to work.https://youtu.be/NgsZaBw2OD8https://youtu.be/iFrxyJAtJ7U
Is this solid state lithium battery a real thing, or BS? - Page 1
Forum section: electronics / general

author: BrianHG
author_rank: Super Contributor
timestamp: March 10, 2017, 09:49:50 am
content: Is this solid state lithium battery a real thing, or BS?

author: FireFlower
author_rank: Regular Contributor
timestamp: March 10, 2017, 10:24:29 am
content: Nintendo Switch uses same battery?Yeah I think it seems solid enough

author: ConKbot
author_rank: Super Contributor
timestamp: March 10, 2017, 01:27:29 pm
content: True solid polymer electrolyte cells have existed for a while, but havent been commercially viable, have had poor performance at room temperature. Plastic/foil pouch packaged cells that are normal lithium Ion batteries stuffed in a flat pouch instead of a can have usurped the name "lithium polymer" but still use a liquid electrolyte and a porous separator.I'm guessing with developments in polymer electrolyte aluminum caps polymer electrolyte lithium cells have become more viable too.The RC hobby battery video examples used are a worst case scenario where a battery is optimized for current output and low cost. I've messed around with higher quality cells that aren't optimized for current output and when punctured and shorted, they hiss, smoke, but don't flame up or explode.Probably not a BS video, but a lab sample is a far cry from a commercially viable product. But at least this isn't scaled up 1000x from some chemistry experiment. I.E. "New nano material battery charges in 3 seconds and is 5x the energy density of lithum" type need articles that were so popular a few years ago. But the battery was a little 1mAH sample in a test tube.

author: bktemp
author_rank: Super Contributor
timestamp: March 10, 2017, 04:19:15 pm
content: It this video BS? Probably not. But it isn't completely fair:If you short the battery by sticking a screwdriver in it, a high current will flow, unless it has a high internal resistance. This is simple math.The only way around this is splitting the cells into small sections and adding fuses for each cell like the battery packs used in Tesla cars have.I doubt the battery shown in the video has this, therefore it probably has a high series resistance limiting the short circuit current but also making the battery less efficient and less useful for high power loads.When the electrolyte in a lithium gets hot, it decomposes into hydrogen and other flammable gasses. If there is a spark or a red hot glowing wire, the battery explodes.If he solved that problem without degrading the energy density or internal resistance, that type of battery will replace current lithium battery technogy. But since it hasn't already, there are probably some downsides.

author: BrianHG
author_rank: Super Contributor
timestamp: March 10, 2017, 04:29:10 pm
content: My guess is also that he is not getting as much current through his battery as normal lipo. When cutting through a thin his cell with the scissors in the first illustration, even if his battery would not go up in flames, I would still expect to see electrical sparks.
Adafruit going to interview Altium - Page 1
Forum section: electronics / general

author: bitwelder
author_rank: Super Contributor
timestamp: March 12, 2017, 09:52:23 am
content: At their weekly video show Adafruit announced they're going to interview Altium on Tuesday. Perhaps it will be a live video.(Bunnie and Dave mentioned as Altium aficionados)https://youtu.be/NfQfeDCl7Fk?t=22m55sAltium seems to be pretty much focused on taking any opportunity on hitting at the AutoCAD Eagle market.It would be interesting to see if they are going to announce any further 'incentive to switch' for the typical Adafruit audience, i.e. makers.

author: bitwelder
author_rank: Super Contributor
timestamp: March 26, 2017, 01:40:56 pm
content: Ted Pawela in the interview said that in addition to the three existing Altium products, during springtime a new one will be launched, named Tina (?), oriented to teams.https://youtu.be/VkD0fKEcUYY?t=12m0sJust curious, did anyone heard about it?BTW, he also said that it will be only subscription-based, "for technology reasons".

author: amyk
author_rank: Super Contributor
timestamp: March 26, 2017, 02:13:55 pm
content: https://en.wikipedia.org/wiki/TINA_(program)Unless Altium bought them, that would be a very bad choice of name...

author: rx8pilot
author_rank: Super Contributor
timestamp: March 26, 2017, 05:25:55 pm
content: Altium has been bombarding me with calls and emails. I keep telling them I don't like Eagle, but cannot afford to go through the transition of learning and getting all my current designs re-done in Altium.The end result would most likely be a massive step up, but the time needed to get there is too much to handle.Sent from my horrible mobile....