hybridfree/eevblog-posts huggingface dataset:
"Protected" lithium cells - Page 1
Forum section: electronics / projects

author: jd
author_rank: Contributor
timestamp: September 04, 2015, 10:44:20 am
content: Hi,We are designing a rechargeable version of a product.Has anyone used "Protected" li-ion cells in "professional" applications?I can't seem to find much technical data. (Temperatures, protectionrequirements, lifetime. UN Certification requirements?).There are dozens of scary sounding consumer brands:http://www.amazon.co.uk/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=18650+protected"Trustfire", "Ultrafire".... so *Not* the name I want to see on alithium battery.ThanksJohn

author: Akra
author_rank: Contributor
timestamp: September 04, 2015, 11:07:08 am
content: Sry, i have no technical data for this cells,but be aware, you get what you paid for.This "Ultrafire" etc. Brand Cells are mostly china fake ones.Just enter the names in Youtube for example and you can see many tests of this products and how bad they are.

author: dexters_lab
author_rank: Unknown
timestamp: September 04, 2015, 11:29:29 am
content: yea, anything that has ultrafire on it will probably be some kind of fake or be of poor qualitytry Xtar, well respected in the vaping community, they sell panasonic cells with protection. I use them myselfthey are sold through a number of EU official distributors so should have relevant certshttp://xtar.de/
"rail to rail" opamps - Page 1
Forum section: electronics / projects

author: blackjames
author_rank: Regular Contributor
timestamp: August 26, 2012, 08:14:07 am
content: hey guys and girls. does anyone happen to know if a lm358 dual opamp is a "rail to rail". if not, is there a rail to rail opamp with the same pinout in a dip-8 package. oh, and it must be able to run from 12V

author: T4P
author_rank: Super Contributor
timestamp: August 26, 2012, 08:27:08 am
content: no read the datasheets.RR I or O? Which one do you need or do you need both?http://sg.element14.com/jsp/search/browse.jsp?N=203333+110106794+110194056+110201817+110203418+110143499+110203475+110153802+110164512+110193321+110154163+110438682+110192203+110122037+110182464+110122189+110164563+110132412+110175723+110190058+110132415+110121815+110143097+110132747+110153833+110172659+110179247+110121757&Ns=P_PRICE_FARNELL_SG%7C0&locale=en_SG&appliedparametrics=true&getResults=true&suppressRedirect=true&isRedirect=&originalQueryURL=/jsp/search/browse.jsp%3FN%3D203333%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_SG%26divisionLocale%3Den_SG%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D203333

author: PSR B1257
author_rank: Frequent Contributor
timestamp: August 26, 2012, 08:48:01 am
content: QuoteAlmost every (not 100% sure, maybe even any) dual op amp in a dip-8 package, has the same pinout.You can also check out the parametric search of the manufacturer website e.g. LT:http://parametric.linear.com/operational_amplifiers_%28op_amps%29#!cols_1030,1006,1021,1023,1012,1047,1866,1367,1004,1075!s_1004,1!gtd_!1030_2!1047_yes!1075_yes

author: Rerouter
author_rank: Super Contributor
timestamp: August 26, 2012, 09:20:28 am
content: or a TS912INused them in a number of designs so far and havent had any issue with them

author: blackjames
author_rank: Regular Contributor
timestamp: August 26, 2012, 09:52:30 am
content: I think i will use the TS912 opamps because price dosentmatter that much. All specs are better anyway.

author: nctnico
author_rank: Super Contributor
timestamp: August 26, 2012, 07:59:23 pm
content: I recall some of the TS9xx opamps having a very large input current. So beware if the amplification is wrong.

author: blackjames
author_rank: Regular Contributor
timestamp: August 27, 2012, 05:32:35 am
content: ill do some tests once i order them
'Reverse Gullwing LED' - other names? - Page 1
Forum section: electronics / projects

author: ludzinc
author_rank: Unknown
timestamp: September 25, 2015, 01:42:24 am
content: Hi allI'm trying to locate some leds (preferably 0805 package) that can be reverse mounted to the PCB and are flush with the pcb.Something like the OSRAM Top LED here (http://au.mouser.com/Search/Refine.aspx?Ntk=P_MarCom&Ntt=191136680) but in a smaller package.Is there a different term I should be using (rather than 'reverse mount').ThanksSimon

author: ataradov
author_rank: Super Contributor
timestamp: September 25, 2015, 01:58:07 am
content: DigiKey calls them 'Surface Mount, Bottom Entry'. But they won't be exactly flush, of course.

author: georges80
author_rank: Frequent Contributor
timestamp: September 25, 2015, 03:09:29 am
content: Here's a 1206 that is reverse mount. Sits inside a hole in the PCB and the height is less than a standard 1.6mm thick PCB so is flush/below flush with the opposite side. Good for reverse lighting things that sit on the other side of the PCB (such as various plastic moldings/light pipes etc. Basically an upside down LED.http://www.digikey.com/product-search/en?KeyWords=160-1456-1-ND&WT.z_header=search_gocheers,george.
"robot" to ring Tibetan singing bowl? - Page 1
Forum section: electronics / projects

author: djacobow
author_rank: Super Contributor
timestamp: January 29, 2014, 06:18:22 pm
content: I'm building an alarm clock project that will use an RPi to announce appointments from Google Calendar. I would like the announcement to come from a real physical object rather than .wav file and like the sound of Tibetan singing bowls.This isn't really an electronics question per se. I think I'll have little trouble with the RPi, getting the calendar data, and driving motors. (actually I've already got the calendar code working). However, I don't know how to build the actuator. I want something that is:- quiet (don't want motor to be very audible relative to bowl)- simple (probably will have to make any box, arm, etc from wood)- cheap-ish (<$100)- won't be super janky looking in the endAnybody have good suggestions?By the way, these bells are not rung by striking them, but by circling them lightly with a wand. My initial conception is motor mounted above bowl on overhead support, arm with length slightly less than radius of bowl mounted on motor shaft with want attached by hinge. The motor would spin slowly enough that the wand's own weight would keep it in contact with the bowl.For those unfamiliar, this is what I'm talking about:(minus the spiritual mumbo jumbo)Any better ideas?Regards,Dave J

author: fcb
author_rank: Super Contributor
timestamp: January 29, 2014, 06:31:59 pm
content: Spin the bowl - buy a lazy-susan or lazy-susan bearing, then use a large o-ring (or make one - it's pretty easy to join o-ring material together) and drive it with either a shaded-pole motor or perhaps, stepper or what ever you can find.I'd spin the bowl and have some LED's lighting it (candle effect code).

author: djacobow
author_rank: Super Contributor
timestamp: January 29, 2014, 06:43:11 pm
content: Fcb, thanks! I'm glad I asked. Yes, turning the bowl makes more sense!Maybe could repurpose parts from an old turntable, perhaps.

author: fcb
author_rank: Super Contributor
timestamp: January 29, 2014, 06:45:11 pm
content: Ommmmmmmm.....You have chosen wisely grass-hopper.

author: djacobow
author_rank: Super Contributor
timestamp: January 29, 2014, 06:54:44 pm
content: Ha ha, we will see! I think it will be nice to wake up to this sound rather than a buzzer.Were you suggesting that the o-ring surround the entire rotating platform and be driven by a motor in contact with it at the edge? Because that's the picture in my head right now.

author: fcb
author_rank: Super Contributor
timestamp: January 29, 2014, 07:16:47 pm
content: You could do it like a turntable (o-ring round the OD), or you could use just push the motor shaft against the OD of the turntable (perhaps use an o-ring to give you a grippier surface).I'd do it like a turntable personally, but I don't know how much friction the wand applies and if that would cause slipping.
"standard" bananna jack spacing? - Page 1
Forum section: electronics / projects

author: george graves
author_rank: Super Contributor
timestamp: November 16, 2012, 10:07:56 am
content: Anyone know off the top of their head the standard banana jack spacing that most power supplies and DMMs use? My calipers are on the fritz.It seems to be 0.75 inches - or is it a close metric value?

author: BravoV
author_rank: Super Contributor
timestamp: November 16, 2012, 10:09:59 am
content: 3/4 inch

author: george graves
author_rank: Super Contributor
timestamp: November 16, 2012, 10:13:38 am
content: I love this forum - an answer at 2am - inside of 2 mins.Thanks you BravoV.

author: BravoV
author_rank: Super Contributor
timestamp: November 16, 2012, 10:42:12 am
content: Quote from: george graves on November 16, 2012, 10:13:38 amMy pleasure, just fyi, I've spent quite intense for sometime while ago working with this banana spacing, thats why I can answer that even without blinking.Like this when my uCurrent had problem with the banana connector's spacing....or this ... LOL ... now you know why.

author: robrenz
author_rank: Super Contributor
timestamp: November 16, 2012, 12:55:00 pm
content: Its not 3/4" it is 19.05mm

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 27, 2012, 06:08:35 pm
content: I believe the banana plug was invented by the General Radio Corporation, who probably also set the spacing. It's more critical than most people realize if you want to keep the stress on the dual plugs to a minimum. If you can't set it with a mill, at least scribe accurate lines, use a center punch, then drill with several increasing sized drill bits. You can also go a bit oversize and adjust later but it's just never quite as good.good stuff here-http://www.teradyne.com/corp/grhs/
"sticky" stannol HS10... - Page 1
Forum section: electronics / projects

author: mcinque
author_rank: Unknown
timestamp: August 19, 2014, 11:20:31 am
content: I've used Multicore 60/40 for almost 10 years without any issues. As you know, it's Sn/Pb based and have rosin fluxat 5%at 3%.I've got the bad idea to try the well known HS10 by Stannol. Same melting point, same Sn/Pb ratio; it have only 2.5% of rosin flux but I thought this wouldn't be a problem.Well, now that I've tried, it seems that the HS10 behaves basically like a solder wire without flux or a solder that has been heated for too long (with all the flux burned): it tends to be sticked to the iron tip and to create sharp points when I lift the iron tip. Awful.Sometimes it seem that I began to solder this week.With the multicore, my iron tip never had much tin on it (all the tin is transferred to the solder joint), with HS10 I have always a drop of solder sticked to the tip.How can I have so much difference between this two solder wires?Any of you use HS10?

author: bktemp
author_rank: Super Contributor
timestamp: August 19, 2014, 01:17:38 pm
content: I am using HS10 for some time. I can not confirm your experience. I would even say it has some rather strong flux in it. It leaves nasty brown/black residues on the board.I think there is something wrong with your solder wire. Try to skip a meter or two, maybe there is a small part with missing flux.
'Throttle Joystick' - Page 1
Forum section: electronics / projects

author: BurnedResistor
author_rank: Regular Contributor
timestamp: December 05, 2015, 12:21:05 pm
content: Dear All,For my current project I am designing a remote control.Many of the cheap remote controls I have looked at or handled did not have a spring on the vertical of the left joystick. In other words, the left joystick would only snap into the center horizontally, but the vertical position would not latch back.I am trying to figure out where I could by these types of joysticks/What they are called!Does anyone have any insight?Many Thanks!

author: rs20
author_rank: Super Contributor
timestamp: December 05, 2015, 12:45:51 pm
content: Buy a normal, double-springed joystick and hack away the springs?

author: BurnedResistor
author_rank: Regular Contributor
timestamp: December 05, 2015, 04:11:17 pm
content: All the ones I have seen use one springy base in the bottom to push both axies back into position...

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 05, 2015, 04:23:20 pm
content: Quote from: BurnedResistor on December 05, 2015, 04:11:17 pmI have 5 or 6 different kinds here in the workshop, and they all have separate springs for each axis.And they are essentially trivial to remove.OTOH, you could use something like a slide pot for that kind of fixed, linear control.

author: BurnedResistor
author_rank: Regular Contributor
timestamp: December 05, 2015, 04:29:26 pm
content: Could you please post a picture of the type of joysticks you own?

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 05, 2015, 04:55:52 pm
content: Quote from: BurnedResistor on December 05, 2015, 04:29:26 pmAh! I think I see the disconnect here. All the joysticks I have are the smaller ones used for things like Radio Controlled vehicles, etc. They use potentiometers for ANALOG readout of position. They have separate springs for X- and Y-axis movement.But the larger, metal kind used for arcade game machines have a single restoring spring at the bottom. They aren't really "joysticks" by my definition. They have only switches for BINARY readout of movement.

author: BurnedResistor
author_rank: Regular Contributor
timestamp: December 05, 2015, 04:58:00 pm
content: That really clears things up! Thanks!

author: Nerull
author_rank: Frequent Contributor
timestamp: December 05, 2015, 10:44:37 pm
content: The R/C type are often custom assemblies, and are often called 'gimbals'.Forex:http://www.lynxmotion.com/p-839-aurora-9-gimbal.aspx
"turbo PLL" for old server motherboard? - Page 1
Forum section: electronics / projects

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: May 31, 2015, 09:42:39 pm
content: A few of us are building "old" computer systems, namely from 2003-2004.I have a dual Xeon server motherboard, that I plan to run dual 3.06Ghz cpus in.Sadly, the board doesn't allow any overclocking, as the PLL isn't programmable.I found this here:http://www.overclockers.com/do-it-yourself-pll/And am looking to do something similar, although my board has a different PLL, namely an ICS932S203:http://lmgtfy.com/?q=ICS932S203I have a query though...Why the need for the hex inverters on the 48Mhz and 14.318mhz oscillator outputs?He says they "serve to amplify the crystal oscillators outputs" But then, he's only running the oscillators at 3volts, because that's all the signals are meant to be at?Thanks!
"Unlocking" the GTX 670... - Page 1
Forum section: electronics / projects

author: Mawson
author_rank: Newbie
timestamp: April 17, 2013, 02:20:21 pm
content: HI everyone! I'm a bit of a novice in this end of things, but my Google-Fu and desire to learn are equally strongI am planing a couple of over the top mITX builds, and have been putting a good little bit of though into how it might be possible to have a fully unlocked GK104 chip on a reference 670 PCB, or, better yet, Asus' new DC Mini board, with it's upgraded power delivery. Why? because having a dead core in a main component of a build that will be packed to be gills justbothersme. Its all about overkill.The big question is how that 8th core is disabled? Is it done on the PCB, or the chip itself? If it is on the board great, but even if that is the solution that still leaves the unknown of whether the core is disabled for a reason, and how to enable it in the first place! If it's on the chip, or we can't determine then we go to plan B...My plan B would be to have someone with experience remove the chip from a 670 and a 680 and swap them for science. The results of that would tell us a lot, and possibly show what needed to happen to do this without chip swapping. Another thing to do would be to compare reference 680's to 670's that use 680 boards to see how they were populated differently.Now assuming the worst, that the core is locked on the chip and we can't do anything about it then swapping chips with a DC mini and a high binned card like the lightning would be the ideal solution, provided that swapping chips can be made to work.What are your thoughts?
:: a 1 part easy to use potting compound? :: - Page 1
Forum section: electronics / projects

author: 3roomlab
author_rank: Frequent Contributor
timestamp: October 09, 2013, 11:36:34 am
content: hello yall,i am curious to search for (and use) a 1 part potting compound, to be applied onto some normal 230V AC pathways.i searched and the web gave me thishttp://www.masterbond.com/products/one-component-epoxy-systemsi have tried some 3M products before, but i have lost the contact of the supplier.so question is, has anyone have any good experience in some of these? has good insulation against AC voltage? preferably clear?cheers n thanks for reading

author: ConKbot
author_rank: Super Contributor
timestamp: October 09, 2013, 02:00:08 pm
content: One part epoxies aregenerallymore difficult to keep/store, have to be kept in freezers or fridges, have a short shelf life, are made to order, therefore have a large minimum order quantity etc... Some may not which would be nice, but then I'd expect it to be loaded with VOCs then.If youre just looking for ease of dispensing/use I'd look at stuff in a 50mL dispenser cartridge and use a dispensing baffle, I.e.http://www.epoxies.com/products/triggerbond/I havent used it but the 20-2621 is a clear urethane potting with no requirements to bake, and may be of interest. IIRC, epoxies.com has a 5 unit minimum order, which isnt horrible imo.Mcmaster carr has a large variety of epoxies/urethanes in cartridges that may be worth checking out too.

author: 3roomlab
author_rank: Frequent Contributor
timestamp: October 09, 2013, 02:20:30 pm
content: thanks for the infoibe checking those out

author: madsci
author_rank: Regular Contributor
timestamp: October 09, 2013, 07:59:31 pm
content: Have you considered a silicone material that does not release acid when cured?These have superb dielectric properties, won't crack and are dispensed in one part.
A 350V/100mA PSU - Page 1
Forum section: electronics / projects

author: ElectronSurf
author_rank: Regular Contributor
timestamp: July 23, 2021, 08:14:06 am
content: I finished building a high voltage constant current source that I'm going to use it for testing diodes and leakage currents. I'm just a hobbyist, I'm sure there are errors and mistakes in the schematic/built.I'm posting this here so that I can get reviews and improve my current and next designs, any suggestion is very much appreciated.Pictures of the built:https://imgur.com/a/rbcGN4LThe schematic is attached.

author: ElectronSurf
author_rank: Regular Contributor
timestamp: July 23, 2021, 05:15:43 pm
content: May I have your opinions please?

author: bdunham7
author_rank: Super Contributor
timestamp: July 23, 2021, 05:28:46 pm
content: I'm not clear about the connections at J4, so I have to guess where stuff goes.What is the source for the AC input at J2?You haven't shown the MCU control circuitry, perhaps you could describe its operation?If I understand this correctly, the entire output is floating at a voltage of about 350V above your 'GND' symbol. Is that sufficiently isolated so that you could safely connect the negative output terminal to a physical ground? There's a lot of energy there.If it is reliable, it looks like a very interesting and handy project.

author: ElectronSurf
author_rank: Regular Contributor
timestamp: July 23, 2021, 06:24:17 pm
content: J4 is the output, it's connected to a switch and that will connect the output banana plugs to the source or a 1K resistor to discharge the test capacitor.J2 is a transformer with 12 taps with different voltages from 8V to 350V that can output 250mA max. I'm switching between the taps with a selector.The MCU acts as a meter, measuring and displaying output voltage and current, plus a few more functions.If the output current range set to 1mA it's perfectly safe, but at 100mA range it definitely have a nasty shock.The floating ground is limiting the current, there's no limit on the actual ground...I posted a link to the images of the device, the transformer is visible there.
A 'pointless' project - demo and circuit - Page 1
Forum section: electronics / projects

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: September 30, 2012, 07:21:18 am
content: Sometimes projects most popular with non-electronics visitors are items that others would consider pointless. Especially in the area of art and music where people either love or hate the visual or audio result.And even though it's not needed the more obscure projects can answer questions like the maximum output power you can squeeze from a transistor, fewest parts you could use for a particular function, or the most number of stations you can pick up with a one transistor radio.Or, as in this case, the largest number of strange noises you can get out of a simple hex inverter IC. Below demonstrates a simple drone machine buildable by even a beginner (although it can get expensive unless you have lots of old high value pots and switches). The circuit appears near the end.It came about because the original unit was such a hit at a party that a friend requested one of his own. The unit shown is the result. It was built almost entirely out of salvaged parts (including the 1960s Rola speaker) but should satisfy when he gets it.

author: poptones
author_rank: Frequent Contributor
timestamp: September 30, 2012, 08:28:09 am
content: WARNING: THIS VIDEO WILL ANNOY AND PISS OFF OLD PEOPLE

author: GeoffS
author_rank: Unknown
timestamp: September 30, 2012, 09:08:08 am
content: Not just old people, everybody!

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: September 30, 2012, 09:16:30 am
content: Annoying some may consider it, but isn't it wonderful that just an inverter chip, capacitor and resistor can generate sounds?And that because of beat notes and interactions the end result is more irksome than the sum of the parts?
A 'spectacular' LED product I've been working on.... - Page 1
Forum section: electronics / projects

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 31, 2012, 07:39:52 am
content: http://technologywillsaveus.org/2012/05/bright-eyes/

author: DrGeoff
author_rank: Frequent Contributor
timestamp: May 31, 2012, 07:45:12 am
content: Not quite the same as a Deadmau5 helmet though!

author: pickle9000
author_rank: Super Contributor
timestamp: May 31, 2012, 08:14:52 am
content: Man you get to do some fun stuff. Can't wait to see what's next....

author: EEVblog
author_rank: Unknown
timestamp: May 31, 2012, 09:03:34 am
content: Cool. But I don't get it, save us from what?Dave.

author: EEVblog
author_rank: Unknown
timestamp: May 31, 2012, 09:05:49 am
content: Quote from: EEVblog on May 31, 2012, 09:03:34 amOh, that's the name of the group!Got it, I'm having a bad day...Dave.

author: metalphreak
author_rank: Frequent Contributor
timestamp: May 31, 2012, 11:00:24 am
content: Saw this on hackaday:http://hackaday.com/2012/05/22/macetechs-led-glasses-prototype/Thought it was kinda cool but a bit "prototype" looking. What you guys have looks way better!Not to mention better animations and stuff.Is there any purpose to it other than fashion and nightclubs/ravesI assume there's going to be some more info on the hardware design and stuff coming in the future?
A battery booster gadget that would actually be useful - Page 1
Forum section: electronics / projects

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 19, 2015, 05:40:38 am
content: Who else doesn't like that the 9V battery is still in common use? What if we made a boost adapter that takes one AA and converts it into a 9V?Just going by what I could get locally, one NiMH 9V battery is $8. Compare that to a 4 pack of NiMH AAs that's $7. Moreover, the 9V is 150mAh while the AAs are 2000mAh. So in theory, just one of those AAs would be equivalent to over two of the 9V in capacity. And the 9V requires a charger just for 9V while the AAs can be charged in a common AA charger.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 19, 2015, 06:26:50 am
content: I'd like a 9V format cell with internal LiPo cell, booster and a USB charge socket in the bottom.

author: jitter
author_rank: Frequent Contributor
timestamp: September 19, 2015, 06:40:03 am
content: Quote from: NiHaoMike on September 19, 2015, 05:40:38 amI don't mind, they do still have their purpose.If you look at in mWh instead of mAh, it looks different:9 V / 150 mAh > 1350 mWh1.2 V / 2000 mAh > 2400 mWh.Now it's not more than double anymore. I also wonder what the booster itself is going to consume (efficiency) from the AA that lowers the difference even further...Perhaps pitch you idea to the Batteriser people?

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 19, 2015, 07:32:31 pm
content: I'm pretty sure all the cheap "9V" batteries are only 6 cells. Most devices run just fine, but there are 7 and 8 cell versions for more picky devices.

author: eneuro
author_rank: Super Contributor
timestamp: September 19, 2015, 11:35:30 pm
content: Quote from: jitter on September 19, 2015, 06:40:03 amWhy do you put there divide/sign?Code:W ~ V * A12V * 63 Ah ~ 0.756 kWhIt doesn't make any sense put anything else than multiply * sign... to get wats from VA

author: jitter
author_rank: Frequent Contributor
timestamp: September 20, 2015, 06:34:31 am
content: Quote from: eneuro on September 19, 2015, 11:35:30 pmI used it here as a non mathematical separation sign, not the divide sign. Sorry if I caused confusion.
A beautifully restored Ampex playing an Apollo 16 tape 2 inches of tape goodness - Page 1
Forum section: electronics / projects

author: apollo16uvc
author_rank: Newbie
timestamp: September 07, 2017, 08:31:02 pm
content: No nilly willy DVD players here, no sir. It is time for some proper video record and playback machines.2 inch width tape of analog video and audio goodness. Apollo 16 played on a beautifully restored Ampex VR-2000B. Most likely a compilation of the best bits as broadcasted by NASA at the time, and recorded at a TV station.This awesome machine is only running today because of the passion and care given to it by people. A lengthy restoration process resulted in a prime example of Ampex Quadruplex players. It is always great to see work finally paying off.The restoration process can be followed from here, starting with Episode 1:Thank you very much Zdenek Houska for your time and effort. It has been very much appreciated.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 07, 2017, 09:12:57 pm
content: Nice video.The stuff I used to maintain was the Ampex VPR-6, TBC-7 1" combos. There's nothing like the 2" Quad though. That system took up quite a bit of rack space, not to mention the fiddling to keep it running. The 1" was down to a compact, mere 1/2 rack.I bow down in humility to the "Quad Gods" who maintained (and still do) those beasts.Now as for that paint brush used to clean the camera lens, it probably cost the taxpayer about $100.00.
A better mousetrap build / SWR bridge , coupler ? - Page 1
Forum section: electronics / projects

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: February 16, 2022, 09:26:51 pm
content: Looking at building a [ not a mousetrap, SWR bridge & coupler .Uses would be starting with ham radio , but other home uses , checking broadcast TV frequencies , also would like to do up 3-6 Ghz for improving cell , wifi etc. - putting up outside antennas ?May require building more than one for all frequencies ?I do have a Rigol 815 TG , looked at their SWR bridges - but for the cost ?Also bought one of the cheap 4-port RF bridges 0.1-4000Mhz - planning on making a box for it , either metal or plastic , then put metal foil on inside - for plastic .I like the 4 port so I can setup for 50 Ohm , 75 Ohm etc.So looking for suggestions on , hopefully better than the cheap ebay boards - maybe even rework the ebay board ?Same with a coupler , but those are not $300-600

author: bob91343
author_rank: Super Contributor
timestamp: February 17, 2022, 12:02:40 am
content: I have an S parameter test set that could be repurposed for that.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: February 17, 2022, 01:06:07 am
content: More info would help ?But I can only guess at this point your talking about something that is far past the cost of the Rigol SWR bridgeMaybe you didn't pickup on / or I did not make the point well enough - make something better than the $15 ebay board SWR bridge - that cost less than the Rigol device ?

author: bob91343
author_rank: Super Contributor
timestamp: February 17, 2022, 01:35:28 am
content: John, the ARRL handbook, any edition, has projects to build SWR meters. They are simple and cheap. You can also get one free from a ham who no longer uses his. Thousands of them were made cheaply for CB testing. I have several.Having said that, my SWR meter of choice is the nanoVNA which can plot a graph over any frequency range. It's easy to use, and has many other handy functions such as measuring transmission lines, impedances, individual components, filters, and so on.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: February 17, 2022, 01:48:35 am
content: I'm not looking for a SWR meter , I have a bunch .I'm referring to making an SWR bridge as an accessory to my Rigol 815 spectrum analyzer ?

author: bob91343
author_rank: Super Contributor
timestamp: February 17, 2022, 05:56:52 am
content: That's where my S-parameter test set might come in.
A big mistake - Page 1
Forum section: electronics / projects

author: navidrct
author_rank: Regular Contributor
timestamp: October 13, 2015, 09:17:04 pm
content: In this pcb track of antenna is go to far of SIM 900And it went through big capAnd it's a big problemDo u know a way to make it workOf course it will be correct in next version of pcbSorry I'm with tapatalk and it crash when I want upload it hereSent from my HUAWEI G730-U00 using Tapatalkhttps://www.dropbox.com/s/0fzo7gt19dt66l4/IMG_20151014_003546.jpg?dl=0
A bit of maths/algebra. - Page 1
Forum section: electronics / projects

author: kvresto
author_rank: Regular Contributor
timestamp: March 03, 2015, 10:58:27 am
content: Hi everyone.I’m working on an RTD project and I’m reviewing some ccts and getting ideas on what to implement. Looking through Microchip App Note AN687, I’ve painfully gotten this far in trying to establish the transfer function. I know is documented in Eq6, but I was hoping to go through the process. How do I account for the voltage drops of the wires in the transfer function? (RW1, RW2, and RW3).Kv

author: dannyf
author_rank: Super Contributor
timestamp: March 03, 2015, 11:48:43 am
content: Easy: all you need to know is that the inverting and non-inverting pins are at the same potential.Once you have the relationship between Vout and V1/V2, you can express V1/V2 in terms of Rwx and the excitation signal.
A bit uncommon solid stage push pull output stage! - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: August 18, 2023, 05:58:35 pm
content: [ Attachment Invalid Or Does Not Exist ]The output amplifier in a Realistic 8791 car EQ/Amp. Perhaps it's actually made by Alpine... it smells japanese and the switches in front are branded ALPS Japan.Common emitter to get more voltage swing since they don't have a switch mode booster circuit, probably wasnt even common back in like 1988The AC coupling from the pull to the push side is a bit odd.The OPT looks like it's sized for around 10-15watts probably.It's labeled 400WProbably more like 100W combined. the front channels use a TA7250BP which lists 23 watts 4 ohms.

author: David Hess
author_rank: Super Contributor
timestamp: August 18, 2023, 10:40:41 pm
content: They already had the center tapped transformer, so why not an all silicon NPN or germanium PNP push-pull?

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 19, 2023, 04:58:29 am
content: It's almost like they are using a stock output transformer in "reverse" so they can get more power out of a limited voltage swing. (12V supply rail)ie: The transistor output stage drives a 1-2impedance and the 4side connects to the speaker.
A Book about electronic manufacturing - Page 1
Forum section: electronics / projects

author: avishorp
author_rank: Newbie
timestamp: June 09, 2015, 02:21:43 pm
content: HiI'm looking for a recommendation on a book coverint the details of electronic production technology and the design of a modern electronic equipment factory.Thanks,Avishay

author: calexanian
author_rank: Super Contributor
timestamp: June 09, 2015, 03:20:02 pm
content: Going to be hard. Technology on the manufacturing end moves so fast. I recommend watching lots of youtube videos of SMT production lines.

author: John_ITIC
author_rank: Frequent Contributor
timestamp: June 09, 2015, 09:35:34 pm
content: There are tons these books on Amazon.com.http://www.amazon.com/s/ref=nb_sb_noss_2/180-7935463-9981523?url=search-alias%3Dstripbooks&field-keywords=electronics+manufacturing
A cheap RTC with integrated crystal - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 07, 2015, 08:53:37 am
content: HiThere are many solutions out there,But I need something with these capabilitiesA RTC chip with integrated crystal in it and should have a serial interface like I2C or SPI,have a small package and should be under 0.6USD at 1K QTY. also having internal RAM would be nice tooI fall in love with M41T62 from ST,the only problem is it's price. Do we have cheaper alternatives? where is china in this market?

author: lm3baker
author_rank: Contributor
timestamp: December 07, 2015, 11:57:24 am
content: I don't know of cheap ones with a built-in crystal (this seems to come with a price premium), but most of the ones with crystals are $1.50+I did spot the NXP PCF2129 at 1.42/ 2000qty from digikey, and also found DS3231 from maxim, but being maxim it costs an arm and a leg ($5 per 1000 or so). [ edit: Maxim has quite a few seehttps://para.maximintegrated.com/en/results.mvp?fam=rtc] Microchip and Rohm don't appear to have the built-in osc type RTC.As for the Chinese options, a quick search gives me the JYRTC-1http://www.jingyuan.com/UploadDrivers/201371155141119.pdf,websitehttp://www.jingyuan.com/Showpro.asp?id=68&biaoming=product5,info in Englishhttp://tongfangguoxin.manufacturer.globalsources.com/si/6008849732923/pdtl/Crystal-oscillator/1132629984/Real-Time-Clock-Module.htmbut I don't have a price on that.I have used in the past some very cheap, low power (<<500nA) devices from NXP in the past (runs for months off the 3.3V 1F cap), but they need crystals.As an aside, it looks like RTCCs have improved a little bit over the last few years (lower currents, SRAM/NVRAM persistent storages).

author: Pjotr
author_rank: Frequent Contributor
timestamp: December 07, 2015, 01:04:32 pm
content: All depends on accuracy. The integrated ones have a premium here, but at a price. If accuracy is not a major issue, a separate crystal stays cheapest. Epson has also some integrated ones.

author: Fungus
author_rank: Super Contributor
timestamp: December 07, 2015, 01:43:49 pm
content: Quote from: ali_asadzadeh on December 07, 2015, 08:53:37 amYep, embedding a crystal into a chip is expensive.Why does it have to be internal though? Crystals are cheap/small.

author: rdl
author_rank: Super Contributor
timestamp: December 08, 2015, 03:25:25 am
content: The ones with internal crystals can be temperature compensated and factory adjusted for accuracy. Using an external crystal it takes a bit of effort to get better than +/- a couple of minutes a month. Something like a DS3231 is specified for +/- a couple of ppm as supplied, which is just a few seconds per month.edit: removed extra word

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 08, 2015, 06:20:20 am
content: Thanks for your help. embedded crystals bring accuracy, The question is why these chips are priced higher than a MCU with lots of capabilities including a RTC!, Maybe chines friends have something cool for us.
A couple of car audio related projects - Page 1
Forum section: electronics / projects

author: Mike Warren
author_rank: Unknown
timestamp: October 25, 2016, 03:37:03 am
content: I thought I'd show off a couple of small recent projects of mine that are targeted at people who install automotive accessory products.The reason I'm happy with them is that these are very low volume products that I'm able to keep the cost down by using very basic parts and assembly techniques. Both are based around a Atmel ATTiny24A.I work at a company whose main business is car accessory installations, and for nearly 30 years I've regularly been asked to devise simple circuits to solve various problems for the installers. I have also been building speaker testers for the installers based around a 555 that makes their job easier.A few years ago I decided to formalise both of these items into products that the company could sell to other similar companies and so started the design process. I had to fit the development in with my normal work so they took a while to develop. We also decided to use them internally for 12 months before releasing them to make sure there weren't any major issues to sort out.The first is the ASV3270http://airsoundvision.com.au/asv3270/. This is a tester that allows some basic checks such as testing which speakers are connected to which wires and the phasing of the wiring. It also includes a basic voltage check, a tone generator and small amplifier and speaker to check for the existence of audio or video. The installers love them and use them on pretty much every job. So far, no one has damaged their tester and some of the installers can be pretty brutal with their tools.The second project is the ASV3222http://airsoundvision.com.au/asv3222/, which is a 4 input programmable switch (solid state relay). This device is able to replace all the small custom circuits I've made over the years and can switch the output on or off based on a decision made from up to 4 inputs and a bunch of timers.It's programmed by connecting it to a Windows computer though a USB interface and using the programming software I wrote.We've had people also use them for non-automotive uses. They are a bit like a mini PLC.I've recently added some extra software functionality to enable it to trigger on edges, but still have to do the documentation before releasing it.
a Data Acquisition System/Data Logger for $30 using an Arduino (and a PC) - Page 1
Forum section: electronics / projects

author: ShortZircuit
author_rank: Newbie
timestamp: December 15, 2011, 04:04:14 pm
content: Sorry if this is not a normal 'forum' topic, but I ran across this yesterday and wanted to share it.Get this free software...http://www.angstromdesigns.com/software/faq/58-labview-arduino-driver-larvaThey have great documentation too...http://www.angstromdesigns.com/software/user-guidesSure beats spending $100's~$1000's+Enjoy!

author: Jimmy
author_rank: Regular Contributor
timestamp: December 15, 2011, 11:34:27 pm
content: CoolWhat I did to log all the data for work is Arduino > PHP > MYSQL > WEB

author: Unknown
author_rank: Unknown
timestamp: December 15, 2011, 11:39:28 pm
content: Quote from: ShortZircuit on December 15, 2011, 04:04:14 pmHow is a free driver for Labview a way of not spending 100's? Labview isn't exactly free!

author: amspire
author_rank: Super Contributor
timestamp: December 16, 2011, 03:09:04 am
content: Quote from: Uncle Vernon on December 15, 2011, 11:39:28 pmThe same site has a free Simple Graph app so you do not have to purchase Labview. It is actually quite a nice idea.

author: Unknown
author_rank: Unknown
timestamp: December 16, 2011, 04:40:33 am
content: Quote from: amspire on December 16, 2011, 03:09:04 amThat is sounding a whole lot lower cost. Nothing against Labview which is priced well above being suited to small applications.

author: amspire
author_rank: Super Contributor
timestamp: December 16, 2011, 04:50:58 am
content: The only problem is that to get the Simple Graphs download, you have to create an account, add Simple Graphs to your shopping cart and order it for $0. You then get sent a download link.Hate that.

author: ShortZircuit
author_rank: Newbie
timestamp: December 16, 2011, 03:29:03 pm
content: LArVa- The Simple Graph app (LAbView Arduino Driver (LArVa)) I had issues using the 'Save' tab but found right-clicking on the graph, going down to 'Export' let me get the data into Excel and chart it out myself.Here is a short article about Arduino and LArVa, as written up in Test and Measurement World:http://www.tmworld.com/article/519857-Build_a_DAQ_system_for_about_30.phpIt's not 100% accurate as you can only control/read from 12 digital I/Os, not 14, as you need 2 for the UART to the USB.@amspire, I don't like the hassle of registering either, but I see the good side would be getting updates on new versions. I hope they release a new version that let you zoom in on the graph to see events with more detail.
A DC motor specified max 15V or 18V, 2A, given input by SMPS 24V - Page 1
Forum section: electronics / projects

author: abdulbadii
author_rank: Frequent Contributor
timestamp: November 30, 2022, 02:01:05 am
content: How is it harmful to a motor if a DC motor specified max 15V or 18V, 2A, given input by SMPS 24V max 2A?

author: Siwastaja
author_rank: Super Contributor
timestamp: November 30, 2022, 01:12:16 pm
content: A DC motor specified to 15V nominal will rotate faster at 24V, and excessive speed wears the brushes out faster. Is it a problem? Maybe, maybe not.Another issue is, if the motor is rated at 2A nominal, if you just plug the motor in to 24V when it's standstill, it will take significantly higher current (stall current), maybe 10A, maybe 20A. The SMPS would probably just enter short-circuit protection mode (hickup protection for example), so the motor would not turn.Solution to this is active current limiting (usually done as a PWM controller driven by a current sense signal), but then it becomes a motor controller design job. But if you do that, then you can also limit the maximum duty cycle, so 24V will not be problem either as you can limit the motor speed.

author: Zero999
author_rank: Super Contributor
timestamp: November 30, 2022, 06:27:59 pm
content: It might be possible to modify the switched mode power supply to give 15V or 18V.If the motor is powered off a PWM speed controller, just limit the duty cycle so the maximum speed isn't exceeded.

author: amyk
author_rank: Super Contributor
timestamp: December 01, 2022, 03:36:29 am
content: Brushed or brushless?A brushless motor will probably easily blow up the controller IC past its maximum rating while a brushed motor is a lot more resilient to short-term or gradual overvoltage.

author: james_s
author_rank: Super Contributor
timestamp: December 01, 2022, 04:16:11 am
content: I've abused small brushed DC motors before, usually they will take 2-4 times their rated voltage or more for a while, but it's hard on the brushes, commutator and bearings.
A digital-analog-digital nixie clock - Page 1
Forum section: electronics / projects

author: ynfo
author_rank: Contributor
timestamp: March 07, 2016, 03:34:27 pm
content: Yes, a pretentious title for yet another Nixie clock projectHowever this is a bit different from other projects in that I'm using an un-modified 1970's multimeter. The idea is to display a voltage equivalent to the time, so e.g. 12:45 becomes 12.45V. The block diagram is RTC -> Arduino -> DAC ->Multi-meter where the arduino reads the time, calculates the required voltage and sends it to the DAC.I was concerned about the last minute digit flickering or being off by one and showing silly times like "12:60" and although this does happen occasionally it's not a problem in real world use. And the clock is still usable as a multimeter!I haven't seen this approach used before so I thought I'd share.More details/pictures athttp://ynformatics.com/2016/nixie-voltmeter-clock/

author: edavid
author_rank: Super Contributor
timestamp: March 07, 2016, 04:47:31 pm
content: Nice! You can do the same thing with a frequency counter.

author: rrinker
author_rank: Super Contributor
timestamp: March 07, 2016, 05:01:05 pm
content: Neat idea. I want that meter.
A diode can stand with 220V ? - Page 1
Forum section: electronics / projects

author: abdulbadii
author_rank: Frequent Contributor
timestamp: August 30, 2021, 02:30:37 pm
content: How come a bridge diode can stand with reverse bias 220V orso, it's pretty high isn't ?

author: PKTKS
author_rank: Super Contributor
timestamp: August 30, 2021, 02:50:17 pm
content: Quote from: abdulbadii on August 30, 2021, 02:30:37 pmTypical SK95 stands 1600V off the shelf w/encapsulationHigher values availableTUBE rectifiers can stand several thousand volts easilyPaul

author: bob91343
author_rank: Super Contributor
timestamp: August 30, 2021, 06:55:16 pm
content: The dirt cheap 1N4007 diodes are rated for 1000V.

author: Ben321
author_rank: Frequent Contributor
timestamp: August 30, 2021, 11:46:14 pm
content: Quote from: abdulbadii on August 30, 2021, 02:30:37 pmThere are semiconductor components that can withstand TENS OF THOUSANDS of volts each, and that when used in series, the set of series components can withstand HUNDREDS of thousands of volts. These are used in HVDC power systems as rectifiers to convert AC to DC, to send over thousands of miles of power lines with no reactive losses (unlike AC which has reactive losses).In fact, the small rectifier diode inside the flyback transformer in old CRT TVs and computer monitors, can withstand over 30kV.
A dropout issue with Mark III PSU design - Page 1
Forum section: electronics / projects

author: xReM1x
author_rank: Regular Contributor
timestamp: September 29, 2015, 04:16:03 pm
content: hi, I have a problem where at voltage lower then 7V the regulator always must have 7V on the input, even if the output voltage is 10mV it still needs over 7V on the input, if the output voltage is higher then 7V then the dropout voltage is fine. (1-1.5V).here is the schematic + download for ltspice *.asc:

author: jitter
author_rank: Frequent Contributor
timestamp: September 29, 2015, 05:06:13 pm
content: Your question is not very clear. I'm assuming you mean that it won't simulate below 7 V input?Well, a look at thedatasheetof the real LT1074 might reveal why. It's generous that it lets you sim down to 7 V, if I were to use this step down regulator, then I would not dare go below the worst case spec of 8 V.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 29, 2015, 05:13:42 pm
content: The linear output stage might have a lower voltage limit due to R10. The base current of the power transistor might give quite some drop there at high currents. Though 7 V would be at high current.

author: xReM1x
author_rank: Regular Contributor
timestamp: September 29, 2015, 06:38:33 pm
content: Quote from: Kleinstein on September 29, 2015, 05:13:42 pmproblem fixedI had to also change the positive voltage on the op amp to 30V and negative supply of 5V.having problemos with the pre regulator doe

author: mikerj
author_rank: Super Contributor
timestamp: September 30, 2015, 07:50:10 am
content: Quote from: xReM1x on September 29, 2015, 06:38:33 pmTry using a buck

author: xReM1x
author_rank: Regular Contributor
timestamp: September 30, 2015, 02:40:32 pm
content: Quote from: mikerj on September 30, 2015, 07:50:10 amthis damn LT1074 what the heck it doesnt matter what resistor value I set R3 and R4 it will be always less then 1V! what.