hybridfree/eevblog-posts huggingface dataset:
battery backup circuit. - Page 1
Forum section: electronics / general

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 21, 2013, 06:34:54 pm
content: I am looking for a simple circuit that switches to battery power to power a Geller voltage reference.

author: yanir
author_rank: Regular Contributor
timestamp: April 21, 2013, 06:48:10 pm
content: Quote from: peterthenovice on April 21, 2013, 06:34:54 pmYou can use a 2 diode selector circuit if your primary voltage source is greater than the diodes turn on voltage and the input voltage of the second diode. Schottky diodes are recommended for both their low lower turn on voltage (typically 0.4v) and high switching speed.there is an example circuit here:http://saeedsolutions.blogspot.com/2012/12/how-to-switch-between-power-supplies.html

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 21, 2013, 06:55:09 pm
content: Quote from: yanir on April 21, 2013, 06:48:10 pmcan you use a transistor with the plug pack connected to the base.

author: yanir
author_rank: Regular Contributor
timestamp: April 21, 2013, 07:08:46 pm
content: Quote from: peterthenoviceYes provided your voltages are all within the range the transistor can handle. I think the attached circuit would work. I've used something like this in a recent design and now the main and backup voltages can be equal. The transistor in the diagram is a PNP.

author: MacAttak
author_rank: Unknown
timestamp: April 21, 2013, 09:03:01 pm
content: Diodes have a voltage drop that needs to be accounted for. Another way to do it is with complementary FETs. A nice example is in the power source switching used here (the part of the schematic labeled "Power" which switches between +5v and +3v sources):(fromhttp://tiny-circuits.com/products/tinyduino/asm2001/#design-files_517452430bf34)It uses a dual MOSFET (http://www.onsemi.com/pub_link/Collateral/NTZD3152P-D.PDF) to cutoff the lower voltage source when the higher source is present.Of course, the two weaknesses here are 1) these are low-power parts (intended for extremely low current device), and 2) it relies on the battery backup power source having a lower voltage than the external power source.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 21, 2013, 09:14:08 pm
content: Quote from: MacAttak on April 21, 2013, 09:03:01 pmsince a 15 volt power pack would be used with two 9v's in serise that would not work

author: ptricks
author_rank: Frequent Contributor
timestamp: April 22, 2013, 12:12:36 pm
content: If you use schottky diodes check the reverse bias limits as schottky are pretty low in that area.

author: yanir
author_rank: Regular Contributor
timestamp: April 22, 2013, 06:11:25 pm
content: Left out a diode. Here is a circuit I'm using for switching between a battery and adapter (power pack to you aussies) for input to a lcd backlight driver. It employs a PNP mosfet to prevent current from being drawn from the battery when there is a voltage (provided by the adapter) present on the Gate.
Brazilian Electronics Channel - Page 1
Forum section: electronics / general

author: Gregory
author_rank: Regular Contributor
timestamp: April 20, 2013, 10:25:04 pm
content: Hello guys! I and a friend started a project inspired on Daves EEVBlog. A electronics channel, here in brazil we don't have this kind of channel and we want to bring free knowledge in a fun way for all. Heres the channel!https://www.youtube.com/user/AllEletronicsGRAppreciate the help of the staff of Brazil. We are looking for more people to take lessons. Subscribe!Grégory
ABB's fibre optic current sensors (FOCS) - Page 1
Forum section: electronics / general

author: nitro2k01
author_rank: Frequent Contributor
timestamp: April 19, 2013, 07:30:23 pm
content: http://www05.abb.com/global/scot/scot232.nsf/veritydisplay/8b0e30a9775871f6c1256f9b0048c488/$file/3BHS209603_E01_Rev-_ABB%20FOCS%20Data%20Sheet.pdfThis reminded me of Dave's April fool from last year, of a laser high voltage sensor. This technology allows you to coil an optic fibre around a high current busbar, and read the current from the phase shift between the electric and magnetic part of the light wave (if I understand the technology correctly.) And this is apparently not a joke. Pretty cool and high precision stuff.

author: M. András
author_rank: Super Contributor
timestamp: April 19, 2013, 10:43:20 pm
content: wow thats a pretty good technology. no wonder how do they get every big project

author: EEVblog
author_rank: Unknown
timestamp: April 20, 2013, 12:14:36 am
content: Fibre can be used for all sorts of sensors apps.Fibre optic underwater hydrophone sensors have been the holy grail of the seismic industry for the last 30 years or something.http://traktoria.org/files/sonar/hydrophone/a_fibre_laser_hydrophone.pdf

author: digsys
author_rank: Unknown
timestamp: April 20, 2013, 12:21:39 am
content: You just reminded me of a project that I forgot to follow up. We make the clip-on type for HV power lines, but a few years ago aUniversity research team showed us a working fiber setup for doing just that. We were supposed to help them make it"manufacturable". I have to find out what ever happened to that project. I can't remember the exact specs, but I can look it up Mon.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 20, 2013, 03:51:58 am
content: Some optical disks are read by bouncing a polarized laser off them and detecting the "twist" in the polarization.

author: jahonen
author_rank: Super Contributor
timestamp: April 20, 2013, 05:37:01 am
content: It's 1800's technology:http://en.wikipedia.org/wiki/Magneto-optic_Kerr_effectRegards,Janne
Festo Robotic Dragonfly - Page 1
Forum section: electronics / general

author: robrenz
author_rank: Super Contributor
timestamp: April 19, 2013, 05:09:08 pm
content: Pretty amazing, the video is cool and very short. Some heavy duty stuff going on to keep that thing in the air both mechanically and electronically.Article link here

author: pickle9000
author_rank: Super Contributor
timestamp: April 19, 2013, 05:18:44 pm
content: CoolFesto company link with 2 vidshttp://www.festo.com/cms/en_corp/13165.htm

author: Bored@Work
author_rank: Super Contributor
timestamp: April 19, 2013, 05:19:08 pm
content: Every other year or so they do some flying machine. Here is an earlier onehttp://www.festo.com/cms/en_corp/9651.htm

author: robrenz
author_rank: Super Contributor
timestamp: April 19, 2013, 06:29:20 pm
content: I had seen the second swam video but the humming bird is more amazing to me from a mechanical perspective.
The $12 Phone - Page 1
Forum section: electronics / general

author: grumpydoc
author_rank: Super Contributor
timestamp: April 18, 2013, 09:26:20 pm
content: Picked up via LWN.net - the$12 Chinese phone

author: Unknown
author_rank: Unknown
timestamp: April 18, 2013, 09:43:57 pm
content: Those industrialist and cunning Chinese, they must be rolling them out by the millions !

author: sorin
author_rank: Frequent Contributor
timestamp: April 19, 2013, 04:12:13 am
content: where can we buy it?

author: kripton2035
author_rank: Super Contributor
timestamp: April 19, 2013, 08:23:03 am
content: written in the article : herehttp://en.mt0755.com/index.htmlall in chinese and send only to address in china ...
Any of you boys been to "C&H Surplus" in Pasadena? - Page 1
Forum section: electronics / general

author: blasto9000
author_rank: Contributor
timestamp: April 17, 2013, 09:43:11 pm
content: I only discovered that store when it was shutting down... the only place I've ever been able to find these Korean War-era pendulum lamp covers I saw once when I was a kid. (I bought 30 of them... 20 I made into workshop lighting and 10 for spares.)http://candhsurplus.com/Since... 2005-06 (I think?) they've been in smaller store in Duarte just a stone's throw from my house. So I go there every other weekend or so to dig through their piles of exotic test and medical equipment and to get my hands dirty.I'm curious to know the history of that place. Aparrently the business has been around since the 1960s but the owner doesn't seem very old.
Researchers Report Super-Powered Battery Breakthrough Wanky Edition  - Page 1
Forum section: electronics / general

author: Sionyn
author_rank: Frequent Contributor
timestamp: April 17, 2013, 08:17:49 pm
content: With currently available power sources, users have had to choose between power and energy. For applications that need a lot of power, like broadcasting a radio signal over a long distance, capacitors can release energy very quickly but can only store a small amount. For applications that need a lot of energy, like playing a radio for a long time, fuel cells and batteries can hold a lot of energy but release it or recharge slowly. The new microbatteries offer both power and energy.in other newsMagic was discovered today and practical and affordable applications for it are now only 30 years awayhttp://news.illinois.edu/news/13/0416microbatteries_WilliamKing.html

author: G7PSK
author_rank: Super Contributor
timestamp: April 17, 2013, 08:38:10 pm
content: Shoulder mount laser cannon?https://www.eevblog.com/forum/Smileys/default/scared.gif

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 17, 2013, 09:41:58 pm
content: 50 years later you can charge a city in a picosecond.

author: MikeK
author_rank: Super Contributor
timestamp: April 17, 2013, 10:14:42 pm
content: Until it's being produced and used it remains in the "Hyped Bullshit" category.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 18, 2013, 02:56:22 am
content: Quote from: MikeK on April 17, 2013, 10:14:42 pmalong with the carbon nanotube eye patches. the kiddies really wonted those.%-B

author: Psi
author_rank: Super Contributor
timestamp: April 18, 2013, 12:24:21 pm
content: CLBattery has started to commercialize a lithium-graphene battery for grid storage and electric cars.It's supposed to have about 3 times the storage of existing lithium batteries.

author: Unknown
author_rank: Unknown
timestamp: April 18, 2013, 12:52:30 pm
content: Ah, it's nanostructure... just hope it takes physical pressure, and not like those other one's that go-up in flames !

author: G7PSK
author_rank: Super Contributor
timestamp: April 18, 2013, 02:34:17 pm
content: More hype and skewed research results, it is about time this became more common.http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-22186220

author: Rick Law
author_rank: Super Contributor
timestamp: April 18, 2013, 09:37:33 pm
content: Quote from: peterthenovice on April 17, 2013, 09:41:58 pm50 years later, you only need to charge a city in the under-developed area of the world. Typical developed nations will use a "vacuum energy extractor" the size of an AA cell, installed in the truck, and will supply power for the life time of the car.When we first stepped on the moon near 50 years ago, I had imagined by today we would be walking on Mars. But, we are certainly earth bound still. How depressing.So, 50 years from now, I fear we would not have moved very far if at all.Rich
Murphy's Law - Page 1
Forum section: electronics / general

author: k7-3d
author_rank: Newbie
timestamp: April 18, 2013, 02:02:46 pm
content: How meny of you an in this posison?

author: c4757p
author_rank: Super Contributor
timestamp: April 18, 2013, 02:05:52 pm
content: I kind of want to make a chart like that and put it on the wall by my bench.

author: Fsck
author_rank: Super Contributor
timestamp: April 18, 2013, 02:11:38 pm
content: I think it'd just depress me if I made one.

author: k7-3d
author_rank: Newbie
timestamp: April 18, 2013, 02:19:29 pm
content: it dusen depress me :-) wen i look at it, it is just fun and a challenge to beat murphy :-)

author: c4757p
author_rank: Super Contributor
timestamp: April 18, 2013, 02:22:18 pm
content: Murphy laughs at your challenge.

author: Unknown
author_rank: Unknown
timestamp: April 18, 2013, 09:28:37 pm
content: This might produce a smile, takes a while to get through...

author: Short Circuit
author_rank: Frequent Contributor
timestamp: April 18, 2013, 10:13:34 pm
content: Stupid has beaten Murphy on numerous occasions

author: nanofrog
author_rank: Super Contributor
timestamp: April 19, 2013, 04:29:11 am
content: Quote from: c4757p on April 18, 2013, 02:05:52 pmI don't know about you, but I'm not sure I'd have enough wall space.Or is this only to be limited to electronics?

author: codeboy2k
author_rank: Super Contributor
timestamp: April 19, 2013, 04:57:20 am
content: what if your name is Murphy? I'm just sayin.....

author: notsob
author_rank: Frequent Contributor
timestamp: April 19, 2013, 05:12:22 am
content: Don't forget "O'FLAHERTY'S LAW" which states ' Murphy was an Optimist '
Using baudline and waveform data - Page 1
Forum section: electronics / general

author: MikeR
author_rank: Contributor
timestamp: April 17, 2013, 12:57:59 pm
content: Hi,New to the forum, heres my first post which links to my bloghttp://urlme.net/blogthats devoted to microphones and acoustics.The entry related to scopes:http://www.urlme.net/blog/?p=2031Details how to load the .wfm file from a Rigol scope using baudline (hence its Linux or OS X related)In summary its possible to display 500 Mhz of spectra in baudline. For 1GS/s waveforms. For otherscopes it willgo as high as 2GS/Sec, or 1GHZ display.Using my TDS1012B I wrote a simple script that grabs the curve data over the USBTMC interface and sends it to baudline, in effect a poor mans spectrum analyser. Whats interesting here is its possible in baudline to decimate the waveform and dive further into the signal details, or simply play it back as audio.Id be interested in a long / 56MB? waveform capture from the DS2000 series to see how baudline copeswith it.BRMike.
digital decade resistance box - Page 1
Forum section: electronics / general

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 15, 2013, 10:37:24 pm
content: I was watching Dave's resistance box video and thought about a digital temperature compensated resistance box. Is this feasible . parts list: digipot microcontroller rotary incoder.

author: mswhin63
author_rank: Frequent Contributor
timestamp: April 15, 2013, 11:33:08 pm
content: It is possible, I was going to make one similar but temperature compensation maybe a difficult one as you would need a compensation for each range and for higher values maybe each resistor.The other problem with temperature compensation is that it would no longer be a totally passive device which is primary a decade box.Temp compensation wouldn't be worth it really.

author: amspire
author_rank: Super Contributor
timestamp: April 15, 2013, 11:50:32 pm
content: Quote from: peterthenovice on April 15, 2013, 10:37:24 pmNot sure what you mean, but it is not easy. Different resistors will have different temp coefficients, and even if you know the temperature in the box, you do not know the temperature of an individual resistor since it is dependent on the current passing through it..I have also observed that for metal film resistors with a coefficient of 50ppm that the behaviour under transient conditions have a different coefficient during the time the body of the resistor is a different temperature to the resistance film.Nothing beats finding low temperature coefficient high stability resistors.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 16, 2013, 01:31:57 am
content: Quote from: amspire on April 15, 2013, 11:50:32 pmnot regular resistors microcontroller controlled digipots

author: mikes
author_rank: Regular Contributor
timestamp: April 16, 2013, 03:09:39 am
content: Do you have any specific chip in mind? Quick look - AD5220, 800 ppm, significant wiper resistance, 20 mA max current (5 mA when "shorted").

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 16, 2013, 03:13:59 am
content: Quote from: mikes on April 16, 2013, 03:09:39 ami had taken a look at the ad5220 chip.

author: mswhin63
author_rank: Frequent Contributor
timestamp: April 16, 2013, 12:00:33 pm
content: Quote from: peterthenovice on April 16, 2013, 03:13:59 amI had looked at those but not enough range to be usable for a complete decade box but fine if looking at value 1K above. But I think their power capability was a bit on the low side so you couldn't use them well on lower values without further current protection.
Scented solder? - Page 1
Forum section: electronics / general

author: Nirios
author_rank: Regular Contributor
timestamp: April 12, 2013, 08:26:04 pm
content: Now I've seen everything. Stumbled across this while searching for desoldering equipment.Indium Wire Solder, .032", Sn63 Pb37, CW-807, 1 lb. Spool• Exceptional heat stability• Compatible with tin/lead, Pb-Free, and high lead-containing alloys• Low Smoking• RoHS compliant• Virtually void-free•Pleasant honey cream scentCan I get mine in a manly pine tree scent?Found at:http://www.techni-tool.com/881SO872

author: Balaur
author_rank: Unknown
timestamp: April 12, 2013, 08:30:41 pm
content: Quote from: Nirios on April 12, 2013, 08:26:04 pmSo how do you melt it then?Designer scents anyone? Old spice maybe?

author: mariush
author_rank: Super Contributor
timestamp: April 12, 2013, 08:30:50 pm
content: That's just the rosin flux burning when soldering. I have an issue more with the name of the solder, Indium, as the solder has no Indium in it.. that's the company name. Indium is actually used in various solder alloys:http://en.wikipedia.org/wiki/Solder#Solder_alloys

author: AndyC_772
author_rank: Super Contributor
timestamp: April 12, 2013, 08:42:06 pm
content: Pb37 and labelled RoHS compliant? £1 says the "honey cream scent" is more like week-old roadkill...

author: smashedProton
author_rank: Frequent Contributor
timestamp: April 12, 2013, 08:53:11 pm
content: You should buy some and sniff it!

author: Unknown
author_rank: Unknown
timestamp: April 12, 2013, 09:15:14 pm
content: Having done a life time of soldering, and re-working equipments or my own projects, the smell of old sweet resin/rosin flux solder,provides a time-line in one's life... it can return me back to days of my youth; those heady days, where Health & Safety never existed,and those fumes from the flux being inhaled, remains within one's memory.

author: ddavidebor
author_rank: Super Contributor
timestamp: April 12, 2013, 09:16:11 pm
content: I've a chines flux that smell of fruit sometimes

author: bitwelder
author_rank: Super Contributor
timestamp: April 13, 2013, 07:30:57 am
content: Wouldn't it be better if the solder actually keeps a slightly UNpleasant scent, so that who's soldering does not tend (instinctively) to inhale the nasty fumes?

author: ivan747
author_rank: Super Contributor
timestamp: April 13, 2013, 11:14:32 am
content: Quote from: vlf3 on April 12, 2013, 09:15:14 pmNothing like the smell of rosin flux in the morning.

author: c4757p
author_rank: Super Contributor
timestamp: April 13, 2013, 11:43:18 am
content: Quote from: bitwelder on April 13, 2013, 07:30:57 amRosin flux smellsdelightful. I had a spool of solder a while ago (can't remember the brand now) that smelled very strongly of pine.

author: Randall W. Lott
author_rank: Regular Contributor
timestamp: April 16, 2013, 04:54:22 pm
content: RoHS compliant.. contains lead. Haha!Internal joke possibly?
the new  gear - Page 1
Forum section: electronics / general

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 11, 2013, 12:46:38 am
content: i now own a hakko fx-888d. it works fairly well.

author: xrunner
author_rank: Super Contributor
timestamp: April 11, 2013, 12:49:34 am
content: Quote from: peterthenovice on April 11, 2013, 12:46:38 amCool. I got the now obsolete 888 a couple of months ago, believe it or not - on purpose. I just wanted that knob. Old schoolI guess.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 11, 2013, 02:38:32 am
content: Quote from: xrunner on April 11, 2013, 12:49:34 amthe new user interface is a little hard to figure out first go,I had to consult the "paper of knowledge",which most like to think they don't need, but that temp LCD is comforting.

author: xrunner
author_rank: Super Contributor
timestamp: April 11, 2013, 12:25:46 pm
content: Quote from: peterthenovice on April 11, 2013, 02:38:32 amI got a Hakko FG-100 tip thermometer off Ebay, not because I needed it but because it was so cheap - $17 - I couldn't pass it up. Well, it's probably a "fake" but it works great. When I tested my non-digital 888 with it, I set the knob to 350 deg C.You know what the FG-100 read?Exactly 350 deg! Not one deg off.I was shocked.

author: ddavidebor
author_rank: Super Contributor
timestamp: April 11, 2013, 01:42:21 pm
content: Shocking

author: Strada916
author_rank: Frequent Contributor
timestamp: April 11, 2013, 02:12:43 pm
content: Quote from: ddavidebor on April 11, 2013, 01:42:21 pmThere is noting wrong with your english Davide.woops sorry off topic.Sounds great.

author: ddavidebor
author_rank: Super Contributor
timestamp: April 11, 2013, 02:16:26 pm
content: What strange i've say?

author: staxquad
author_rank: Frequent Contributor
timestamp: April 13, 2013, 04:46:48 am
content: Quote from: xrunner on April 11, 2013, 12:25:46 pmwhat you got is a Fakko, the Hakko is slightly more expensivehttp://www.amazon.com/Hakko-Tip-Thermometer-FG-100-Fahrenheit/dp/B000PDWE6A/ref=sr_1_1?ie=UTF8&qid=1365828140&sr=8-1&keywords=FG-100

author: Shale
author_rank: Contributor
timestamp: April 15, 2013, 02:45:23 pm
content: Quote from: xrunner on April 11, 2013, 12:49:34 amDont feel bad. I got 2. One for the house, the other is on my service truck.

author: ddavidebor
author_rank: Super Contributor
timestamp: April 15, 2013, 06:05:46 pm
content: Oooh do you have a service truck? Niiice, post a photo somewhere!
Interesting development in Battery Tech - Page 1
Forum section: electronics / general

author: dimlow
author_rank: Frequent Contributor
timestamp: April 18, 2013, 01:33:40 pm
content: http://www.bbc.co.uk/news/technology-22191650Looks interesting but will it ever come to market?Edit: Lol, just noticed someone already posted it herehttps://www.eevblog.com/forum/chat/researchers-report-super-powered-battery-breakthrough-wanky-edition/
PCBCart - reordering a reorder. - Page 1
Forum section: electronics / general

author: Psi
author_rank: Super Contributor
timestamp: April 15, 2013, 01:30:54 am
content: Just wondering if anyone has reordered a reorder using the pcbcart website?I changed a few things in my previous reorder last year, which was fine.But if i now reorder this reorder do i need to keep the previous layer change info or do i select "nothing changed"I'm pretty sure "nothing changed" is the correct answer but i thought id ask just in case it's a trap.

author: David_AVD
author_rank: Super Contributor
timestamp: April 15, 2013, 02:21:09 am
content: I would have thought that the "reordered reorder" would use the most recent file you uploaded. I don't think I've ever changed a reorder myself (apart from qty and lead time) so can't say for sure though.
the least technical term for electronics - Page 1
Forum section: electronics / general

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 15, 2013, 02:55:38 am
content: please describe electronics in the least technical term possible.here is my description:"calibraiak"

author: Rerouter
author_rank: Super Contributor
timestamp: April 15, 2013, 03:01:28 am
content: expensive

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 15, 2013, 03:03:00 am
content: Quote from: Rerouter on April 15, 2013, 03:01:28 ammore like corps want it to be expensive

author: c4757p
author_rank: Super Contributor
timestamp: April 15, 2013, 03:08:51 am
content: Quote from: peterthenovice on April 15, 2013, 02:55:38 amErm.... what?

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 15, 2013, 03:11:10 am
content: Quote from: c4757p on April 15, 2013, 03:08:51 amthe subject is the least technical term for electronics

author: c4757p
author_rank: Super Contributor
timestamp: April 15, 2013, 03:12:38 am
content: ...yeah.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 15, 2013, 03:14:42 am
content: Quote from: c4757p on April 15, 2013, 03:12:38 amleast technical term for electronics equals the craziest one word for electronics you can think of

author: c4757p
author_rank: Super Contributor
timestamp: April 15, 2013, 03:16:58 am
content: News to me. I was just thinking more along the lines of "layman's terms". Ok, pvn4jfrv((. How's that?

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 15, 2013, 03:20:18 am
content: Quote from: c4757p on April 15, 2013, 03:16:58 amcraziest thing since those new fangled mobile phones came out ten minutes ago

author: opablo
author_rank: Regular Contributor
timestamp: April 15, 2013, 07:20:15 am
content: Electrons Whisperers

author: TheWelly888
author_rank: Frequent Contributor
timestamp: April 15, 2013, 07:41:35 am
content: I heard the word "Electronicals" used in a TV advert some years ago.
(Another) simple maths question?  - Page 1
Forum section: electronics / general

author: Things
author_rank: Regular Contributor
timestamp: April 16, 2013, 08:03:43 am
content: Exam next week, booBut working through some problems, I've come across something I'm really struggling to get my head around. I've looked back in my notes and can't really find where I covered this stuff in lectures.Basically, I'm trying to factorize (x+3)2+2(x+3), and supposedly meant to end up with (x+3)(x+5).The first thing I tried was expanding it, so I got:x2+ 9 + 2x + 6, which can be simplified to x2+ 2x + 15, a quadratic.Thus, (x+3)(x+5) makes sense, as 3x5 = 15, but isn't the sum of the 2 numbers (5 + 3) meant to add to "2x"?Probably something stupid I've done again - I'm good at thatDan

author: Psi
author_rank: Super Contributor
timestamp: April 16, 2013, 08:08:52 am
content: The problem is in the expansion, is should be x^2 + 8x + 15(Yeah, i cheated and expanded it with an online calculator. Sadly it doesn't show the working)

author: Psi
author_rank: Super Contributor
timestamp: April 16, 2013, 08:36:04 am
content: OkI think i have figured out the working for expanding it(x+3)2+ 2(x+3)=0Expand first part (x + 3)2Apply rule (a+b)2= a2+ 2ab + b2x2+ (2* (x * 3)) + 32x2+ (2* (3x)) + 9x2+ 6x + 9Expand second part 2(x+3)2x + 6Adding both parts togetherx2+ (6x+2x) + (9+6)x2+ 8x + 15

author: Balaur
author_rank: Unknown
timestamp: April 16, 2013, 08:40:23 am
content: (x+3)^2 + 2 (x+3) = (x+3)(x+3) + 2(x+3) = (x+3) ((x+3)+2)) = (x+3)(x+5)

author: Things
author_rank: Regular Contributor
timestamp: April 16, 2013, 09:20:38 am
content: Quote from: Psi on April 16, 2013, 08:36:04 amAh, of course! Thanks guys
Soldering torch. - Page 1
Forum section: electronics / general

author: houdini
author_rank: Regular Contributor
timestamp: April 13, 2013, 11:23:20 pm
content: This says it can be used for electronics repair. Do you think you could do surface mount stuff with it?http://www.harborfreight.com/interests/welding-2/micro-soldering-and-welding-torch-kit-95671.html

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 13, 2013, 11:39:28 pm
content: Of all the bad ideas in the world, i think that would be up there.I assume it would be for non-electronics soldering, such as jewelry, aluminium soldering/welding and leadlighting ect.Even though it says electronics repair, I wouldn't use it, plus, its freakin expensive if you think about it; $130 + gas you could buy a decent iron for that.
YouTube no longer shows number of video views - Page 1
Forum section: electronics / general

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: April 13, 2013, 04:12:28 pm
content: HiI just noticed the newYouTube pages no longer show how many total video views Dave has had.Anybody else noticed that or is it just the info they are showing me.

author: Skimask
author_rank: Super Contributor
timestamp: April 13, 2013, 04:18:43 pm
content: Must be just you.I see the # of views in the same place it's always been.

author: nitro2k01
author_rank: Frequent Contributor
timestamp: April 13, 2013, 05:43:56 pm
content: With the new channel layout, you have to click "about" and then scroll down to below the text.

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: April 13, 2013, 06:15:35 pm
content: Many thanks nitro2k01BUT, as can be seen in the attachment, it's not there by default Skimask
General Chat Category - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: April 13, 2013, 09:10:59 am
content: There has been quite a lot of posts lately that aren't being put in the right category, and I believe the general consensus on the forum is that posts should be properly categorised.Also, to better reflect the general electronics nature of the forum (as opposed to being an EEVblog forum where it started), I have moved the EEVblog section down in the list and have placed the Electroncis section first.Hopefully this will encourage people to use the proper categories first instead of the General Chat section for everything.ThanksDave.

author: BravoV
author_rank: Super Contributor
timestamp: April 13, 2013, 09:15:35 am
content: finally ... thanks Dave.Suggesting to stick this thread too.

author: ivan747
author_rank: Super Contributor
timestamp: April 13, 2013, 11:31:49 am
content: I will miss the days of endless discussion on those 15 page long threads that inveded this section.

author: Frantone
author_rank: Regular Contributor
timestamp: April 13, 2013, 03:26:51 pm
content: I have learned to be selective about content on the EEVBlog because of this - but General Chat is always where I check for things of interest.
AC clamp meter something to look out for  - Page 1
Forum section: electronics / general

author: BiOzZ
author_rank: Regular Contributor
timestamp: April 11, 2013, 10:56:11 pm
content: so earlier i had my cheap craftman 82372 clamp meter and i went to measure the PRIMARY side of a spot welding transformer i was working on and it jumped up to 85 AMPS ... i KNOW it was not putting out 85 amps on a 15A breaker even for just a secondi remember seeing on one of daves blogs that they use a some sort of hall effect sensor or wire loop so i took it aside and placed it on top of the tranny and turned it on and got 65amp than i put a magnet on the metal loop contact thing and got 8 amps (using the max hold setting) so it was either generating some sort of arbitrary magnetic field or voltage from the triboelectric effect giving a false reading ... granted i was never trained in any way for using clamp meters!this might be very well known or not but i thought id put it out there incase it saves someone some heart ache!

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 12, 2013, 01:11:18 am
content: Clamp meters are inherently sensitive to EMI. The better ones would have shielding and/or multiple Hall sensors to attenuate magnetic fields from outside the clamp.

author: opablo
author_rank: Regular Contributor
timestamp: April 12, 2013, 11:51:32 am
content: A few days ago I bought my first clamp meter (Uni-T UT204 TrueRMS AC/DC) and I don't know what to think...It's either broken.... or clamp meters are shit... Or I have certainly no idea how to use it in a proper/consistent/reliable way.Or... it's unrealistic from me to pretend to use it for measurements with a better than 100mA accuracy.I think that the most probable case is that I don't know how to use it properly...Does anybody know of a video with all the tips around them ?

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 12, 2013, 12:14:01 pm
content: Quote from: opablo on April 12, 2013, 11:51:32 amgo search on yotube.

author: opablo
author_rank: Regular Contributor
timestamp: April 12, 2013, 12:25:12 pm
content: Quote from: peterthenovice on April 12, 2013, 12:14:01 pmI did... And I lost 5 hours of my life watching people selling bad clamp meters, not knowing how to use good clamp meters, doing incredible bad reviews of clamp meters, and talking about clamp meters with less knowledge than what I had prior to even touching one with my hands.I hope that someone like Dave, Mike, Alan or Shahriar made a video about them.

author: Wytnucls
author_rank: Super Contributor
timestamp: April 12, 2013, 12:30:14 pm
content: https://www.eevblog.com/forum/testgear/uni-t-ut204-clamp-meter-review-and-tear-down/msg173734/#msg173734

author: opablo
author_rank: Regular Contributor
timestamp: April 12, 2013, 11:01:48 pm
content: Thanks for the great link Wytnucls.After playing around with my UNI-T UT204,And reading Wytnucls' review of the UNI-T UT204,And reading BravoV's review of the Agilent U1213A,I decided to sell this... thing... that I won't use much... and buy the GTC CM100
Hello Folks. I hope you love electronics as much as I do. - Page 1
Forum section: electronics / general

author: AcousticBruce
author_rank: Contributor
timestamp: April 10, 2013, 03:12:35 pm
content: This forum is actually impressively active. This is wonderful. I have already written on forums and gotten amazing help. I just do not think I officially said hello.I am 29 years old and I am in the process of figuring out if I am going to go to college to be an EE or just keep it as a hobby. I wouldn't be going to college for the money. It is just because I find this stuff so damn interesting. I am hoping that I can buy some used old analog equipment and just tweak, fix, learn, and troubleshoot it when needed and hopefully you folks can come along on the journey with me!

author: smashedProton
author_rank: Frequent Contributor
timestamp: April 10, 2013, 07:03:23 pm
content: From your name, do you do any audio work? An excellent project to to do for audio is to make a chip amp from an hd4780 or something. great fun

author: AcousticBruce
author_rank: Contributor
timestamp: April 11, 2013, 03:51:20 pm
content: Well I do have a tube amp that is most likely oscillating high frequencies and cause a tube to get mad hot. So sure but I am a noob.

author: c4757p
author_rank: Super Contributor
timestamp: April 11, 2013, 03:55:31 pm
content: Quote from: AcousticBruce on April 11, 2013, 03:51:20 pmComplete shot in the dark, buttry this.

author: AcousticBruce
author_rank: Contributor
timestamp: April 12, 2013, 09:56:26 pm
content: I will definitely read this later tonight! Thanks a lot.

author: David_AVD
author_rank: Super Contributor
timestamp: April 13, 2013, 12:03:12 am
content: Quote from: AcousticBruce on April 11, 2013, 03:51:20 pmIs this a design of your own or a commercial item? If the latter, one of the first rules of servicing is to check and clean all connectors. You'd be surprised how many faults can be attributed to the simple things.
Planes can be hacked with a phone? - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: April 12, 2013, 01:49:42 pm
content: apparently air planes can be hacked with a phone so there is no longer any need to smugle explosives on board just walk on with a phone and take over. Well if this report is to be believed.http://www.huffingtonpost.co.uk/2013/04/11/security-researcher-proves-plane-hack_n_3059602.html?icid=maing-grid7%7Cukt2%7Cdl12%7Csec3_lnk1%26pLid%3D171146

author: David
author_rank: Frequent Contributor
timestamp: April 12, 2013, 02:59:31 pm
content: I don't know where to start with this! Basically, in reality, it is simply not possible. The media have taken this out of context completely as always.Dave

author: ddavidebor
author_rank: Super Contributor
timestamp: April 12, 2013, 03:55:30 pm
content: Quote from: G7PSK on April 12, 2013, 01:49:42 pmFaaaaake

author: Skimask
author_rank: Super Contributor
timestamp: April 12, 2013, 04:34:04 pm
content: Looks like that article was posted about 11 days too late...

author: PaulAm
author_rank: Frequent Contributor
timestamp: April 12, 2013, 04:54:03 pm
content: Read the actual articlehttp://www.net-security.org/secworld.php?id=14733It's a proof of concept running in a virtual environment. That does not mean the flaws are not present. Nobody outside the security community thought Stuxnet was possible either.

author: smashedProton
author_rank: Frequent Contributor
timestamp: April 12, 2013, 07:03:04 pm
content: A: Plane flight control systems wouldnt be connected in software to a radio of any kind. Unless you change the firmware of virtually every computer in the plane. Which is impossible. The plane might not even have the hardware to do it.B: Plane radios do not operate at 900 MHz like GSM.C: The interface isn't fast enough to get past encrypion, even if the functionality does exist.Whoever believes this crap is smoking crack
Good solution for holding component reels - Page 1
Forum section: electronics / general

author: LapTop006
author_rank: Unknown
timestamp: April 12, 2013, 09:19:31 am
content: I've been collecting reels of components as I build projects (My simple rule is if a reel is < ~$10 I'll just order it).I'd like to store them in something better then a pile, and was wondering what's out there.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 12, 2013, 12:16:29 pm
content: Quote from: LapTop006 on April 12, 2013, 09:19:31 amyou could use the cunningham method.
Non Delorean based time machine - from Iran - Page 1
Forum section: electronics / general

author: GeoffS
author_rank: Unknown
timestamp: April 11, 2013, 10:57:50 am
content: Apparently not based on any vehicle at all, a bit disappointing.http://www.news.com.au/technology/sci-tech/iranian-scientist-claims-to-have-invented-time-machine/story-fn5fsgyc-1226618432074It's probably a computer based horoscope or based on some similar scientific theory.

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 11, 2013, 11:15:13 am
content: "The reason that we are not launching our prototype at this stage is that the Chinese will steal the idea and produce it in millions overnight."

author: EEVblog
author_rank: Unknown
timestamp: April 11, 2013, 11:45:47 am
content: Quote from: GeoffS on April 11, 2013, 10:57:50 amThat comment somehow reminded me of something I saw at the Easter Show a few weeks back. A fair dinkum Apple IIE running a biorhythm program!

author: MasterOfNone
author_rank: Regular Contributor
timestamp: April 11, 2013, 02:10:05 pm
content: Hot off the press! Here’s a the typical conversion the machine predicts will occur between customers and customer support (when the machine goes on sale).Customer: I want my money back on this time machine because it hasn’t predicted anything correctly yet.Customer support: Well that’s because you have used the time machine to predict your future and so you have changed your future because you know it.Customer: So if I didn’t have a time machine all the things it predicted would have come true.Customer support: Yes 98% of them would. Also you have to remember the disadvantage you would have if everyone else can predict their future and you can’t.Customer: OK I’ll keep it.Quote from: PA0PBZ on April 11, 2013, 11:15:13 amWe can mock it, but the machine probably predicted the Chinese copies flooding the market. And remember if we never see it hit the market and proven to be real, it could be because it has predicted the chaos it would cause, rather than because it’s a piece of trash base on pseudo science.

author: smashedProton
author_rank: Frequent Contributor
timestamp: April 11, 2013, 02:12:55 pm
content: Lets mock it just like Lockheed did when Iran released their stealth fighter/remote control plane!

author: Excavatoree
author_rank: Frequent Contributor
timestamp: April 11, 2013, 03:21:26 pm
content: Quote from: EEVblog on April 11, 2013, 11:45:47 amThanks for the memory, Dave. Back in Junior High School (year 8 ) that was a favorite activity. Crap, that was (cough cough) years ago.

author: kfitch42
author_rank: Frequent Contributor
timestamp: April 11, 2013, 03:23:49 pm
content: Quote from: PA0PBZ on April 11, 2013, 11:15:13 amBrilliant logic!!! If you don't try, you can't fail!!!!!QuoteSo, when he was 17 he write a program:Code:10 PRINT "In 5-8 years you will get posted all over the internet for an obvious con."20 ENDHey it was the prototype, so it was off by a few years.
Is This News? - Page 1
Forum section: electronics / general

author: MITTS
author_rank: Contributor
timestamp: April 11, 2013, 01:11:56 am
content: Looks like iOS for Agilent Wireless DMM

author: EEVblog
author_rank: Unknown
timestamp: April 11, 2013, 01:20:41 am
content: Yeah, I heard they were working on an iPad version.Sensibly they did the Android version first.

author: MITTS
author_rank: Contributor
timestamp: April 11, 2013, 01:24:33 am
content: Dave Have you had a chance to play with the Fluke CNX software. Can it graph from multiple inputs in real time?
Soldering dedication - Page 1
Forum section: electronics / general

author: nitro2k01
author_rank: Frequent Contributor
timestamp: April 10, 2013, 06:10:49 pm
content: The objective: Intercepting the RAM on Nintendo's latest and greatest handheld, the 3DS. How? Using a thin wire and a steady hand, of course. (No, not my pictures. I wish I was this good!)Motherboard, 10% doneIMG_1256byneimod, on Flickr50%IMG_1262byneimod, on Flickr100%IMG_1268byneimod, on FlickrThe RAM chip: 5%IMG_1272byneimod, on Flickr40%Untitledbyneimod, on Flickr100%:IMG_1307byneimod, on FlickrUntitledbyneimod, on FlickrOut you go, signal! (152 wires)Untitledbyneimod, on FlickrThe final rig, covered in hot snot:RAM board setup, right sidebyneimod, on FlickrRAM board setup, left sidebyneimod, on Flickr

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 10, 2013, 06:23:21 pm
content: So, 152 wires coming out, now what? A 152 channel logic analyser?

author: mariush
author_rank: Super Contributor
timestamp: April 10, 2013, 06:47:28 pm
content: I wonder how much the different wire lengths affect the ram signal. Don't they use differential pairs and all that for memory these days?

author: ddavidebor
author_rank: Super Contributor
timestamp: April 10, 2013, 06:49:28 pm
content: what wire can it be?

author: M. András
author_rank: Super Contributor
timestamp: April 10, 2013, 06:59:26 pm
content: prety thin enamelled wire with polyurethane coating melts at solder tempsor similar, i admire his patience,

author: peps1
author_rank: Regular Contributor
timestamp: April 10, 2013, 07:00:09 pm
content: hell of a project, and some good soldering!

author: Bored@Work
author_rank: Super Contributor
timestamp: April 10, 2013, 07:05:42 pm
content: Oh, I thought it was about writing a dedication.LikeDedicated to the flux I love.

author: img
author_rank: Regular Contributor
timestamp: April 10, 2013, 08:36:51 pm
content: Quote from: Bored@Work on April 10, 2013, 07:05:42 pm
Firin Mah LASER At Some Drones  - Page 1
Forum section: electronics / general

author: Sionyn
author_rank: Frequent Contributor
timestamp: April 09, 2013, 07:23:55 pm
content: Navy announced that it plans to deploy its first shipboard laser in the Persian Gulf next year, for use against Iranian attack speedboats and drones. The laser isn't powerful enough to shoot down a missile, but as the video below shows, it can burn right through a small unmanned aircraft.

author: Sionyn
author_rank: Frequent Contributor
timestamp: April 09, 2013, 08:15:16 pm
content: has to be chemical laser could you imagine the amount of power it require if it were electrical

author: G7PSK
author_rank: Super Contributor
timestamp: April 09, 2013, 08:15:36 pm
content: I cant see why that should be any better than radar guided gun fire, other than it will blind optical systems on the target including humans, which would make it an illegal weapon under the geneva convention which prohibits the deliberate blinding of an enemy combatant by a weapon designed to do so.

author: Sionyn
author_rank: Frequent Contributor
timestamp: April 09, 2013, 08:28:43 pm
content: would make it an illegal weapon under the geneva conventiondamn so dave won't be tearing one down soon

author: Codemonkey
author_rank: Regular Contributor
timestamp: April 10, 2013, 06:22:26 am
content: Its not chemical, its solid state, more information here:http://www.theregister.co.uk/2013/04/09/us_navy_laser_cannon/

author: codeboy2k
author_rank: Super Contributor
timestamp: April 10, 2013, 08:25:52 am
content: it's kinda like one of these, only more leds

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 10, 2013, 08:47:25 am
content: I'm currently doing something similar to the above, but with 100W LEDs

author: lapm
author_rank: Frequent Contributor
timestamp: April 10, 2013, 10:06:41 am
content: Well based on that laser video, looks like its much more effective as blinding the UAV's cameras then shooting it down.

author: JoeyP
author_rank: Frequent Contributor
timestamp: April 10, 2013, 06:47:41 pm
content: Quote from: G7PSK on April 09, 2013, 08:15:36 pmSeems no more likely to blind a human than an accurately targeted bit of hot lead through the eyeball.
top 20/50/100 - Page 1
Forum section: electronics / general

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 10, 2013, 02:53:15 am
content: Im loking for the most common resistors needed for most projects, so I know what values i need to buy to keep on hand. metal films on tayda are super cheap.

author: notsob
author_rank: Frequent Contributor
timestamp: April 10, 2013, 02:57:24 am
content: If you are starting out, some of the suppliers have a 'kit' of mixed value metal 1% resistors available, check them on the web first to make sure they are not just trying to get rid of the stuff they couldn't sell.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 10, 2013, 03:03:40 am
content: 1k, 4k7, and 10k seem to be the values I use a lot for pullups/pulldowns. Also useful are 100R and 470R for LED ballast resistors (1k or 4k7 also work well with blue LEDs, actually better if you're going to direct view them) and if you do a lot of low power stuff, 100k and above (up to 1M and 10M) would be essential.

author: peterthenovice
author_rank: Regular Contributor
timestamp: April 10, 2013, 03:12:35 am
content: I think i will get the three Elenco parts kit from amazon;38 bucks all together.

author: MikeK
author_rank: Super Contributor
timestamp: April 10, 2013, 04:14:03 am
content: http://www.ebay.com/itm/251110917128?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

author: EEVblog
author_rank: Unknown
timestamp: April 10, 2013, 04:28:02 am
content: If I had to pick I'd say get 1, 2.2, and 4.7 in all decades.So:10R, 22R, 47R100R, 220R, 470R1K, 2K2, 4K7etc

author: Unknown
author_rank: Unknown
timestamp: April 10, 2013, 03:06:18 pm
content: If your anything like myself, your going to find a value you want but, just don't have; then having to make-up something near that value, best to have the whole range...I recommend the standard values from 10R to 1M; pricing is reasonable for MF 1%.
Dont put boxed wine in the microwave, seriously. - Page 1
Forum section: electronics / general

author: Psi
author_rank: Super Contributor
timestamp: April 10, 2013, 03:29:37 am
content: One moment you have boxed wine and a microwave oven, next moment you don't even have a kitchen.http://www.liveleak.com/view?i=504_1364764525

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 10, 2013, 04:47:10 am
content: http://microwavethis.wikia.com/wiki/9x018_-_Box_of_Wine

author: GeoffS
author_rank: Unknown
timestamp: April 10, 2013, 05:04:46 am
content: Cask (boxed) wine should never be placed in the microwave, place it directly in the garbage bin.

author: Psi
author_rank: Super Contributor
timestamp: April 10, 2013, 05:36:06 am
content: aww, it was cooler when i thought it was real

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 10, 2013, 09:23:22 am
content: Thats fine, our good forum member tesla500 has taken all the hard work out of it for you, watch his video;