hybridfree/eevblog-posts huggingface dataset:
1000 posts crossed?? - Page 1
Forum section: electronics / general

author: GlennSprigg
author_rank: Super Contributor
timestamp: February 10, 2021, 12:19:38 pm
content: Well, I don't think that puts me in any category, apart from obviously generally liking it here!!I'm aware that 'some' would feel that that's probably 1000 too much!!hahaha...All water off a ducks back though... I think all of us, in our own individual ways, have contributed'something'. I think it was an old U.S. President that once said... "You can please all the people someof the time, and some of the people all the time, but you can not please all the people all the time!!Don't have that long now, but thank those for/when their kind comments over the years.

author: Brumby
author_rank: Unknown
timestamp: February 12, 2021, 09:04:46 am
content: Congratulations!Wait till you turn around and see a post count like mine (and there are few here that put me in the shade). You'll then begin to wonder what the heck you've been doing here all that time.I'm glad you worked through a rocky start - it shows a maturity that is appreciated here. I also note your style of "expressive" writing has tempered a little - but is still present. That's one way we know it's you.

author: GlennSprigg
author_rank: Super Contributor
timestamp: February 12, 2021, 11:22:52 am
content: Quote from: Brumby on February 12, 2021, 09:04:46 amHahaha... That's me! Guess I'm too old to change much. (I still like paragraphs looking like pages of a book!)I don't think for a second my 'body' will even allow for 2000, let alone 10000 !!

author: tautech
author_rank: Super Contributor
timestamp: February 13, 2021, 09:23:32 am
content: Keep at it for a few more years and they sure add up.A few years back I started this topic but couldn't keep up with members hitting 1k:https://www.eevblog.com/forum/chat/who_s-this-fella-ticking-over-1k-posts/
Mounting LED's - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: February 04, 2021, 04:15:25 pm
content: I am making an 8mm cine film scanner and going to use an LED for light source. There is not a lot of room for a heat sink so I am going to solder it directly to a chunk of copper. The thing is would it be better to solder the positive or negative to the copper as well or isolate both junctions.

author: ajb
author_rank: Super Contributor
timestamp: February 04, 2021, 10:37:21 pm
content: Assuming you're referring to soldering an electrically isolated thermal pad to the copper, there's no electrical benefit to soldering either electrical contact onto the heatsink. There might be a mild thermal benefit, but it's probably insignificant compared to getting the thermal pad soldered down. If you're using an isolated LED then it really doesn't matter, but if the driver is not isolated you're probably better off not making an electrical connection to the heatsink at all (except possibly connecting it to chassis ground if you have such a think in your device).

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: February 04, 2021, 10:38:42 pm
content: Show us the LED you are wanting to use

author: S. Petrukhin
author_rank: Super Contributor
timestamp: February 08, 2021, 02:26:34 pm
content: It is better not to heat the LED.
Gigantic synced LED displays at multiple high rise buildings - Page 1
Forum section: electronics / general

author: BravoV
author_rank: Super Contributor
timestamp: February 07, 2021, 05:49:37 pm
content: Fast forward the video to 3:23 ... feels like in the movie of Blade Runner's city.Curious if they bought the same and exact LEDs from the same LED factory.

author: DeanA
author_rank: Regular Contributor
timestamp: February 08, 2021, 12:18:31 am
content: That's insane.

author: nctnico
author_rank: Super Contributor
timestamp: February 08, 2021, 01:26:20 pm
content: Quote from: BravoV on February 07, 2021, 05:49:37 pmAnother stolen idea

author: BravoV
author_rank: Super Contributor
timestamp: February 08, 2021, 02:46:05 pm
content: Quote from: nctnico on February 08, 2021, 01:26:20 pmYep, from a sci-fi and turned into reality, just worry they do it on this particular popular sci-fi.

author: BravoV
author_rank: Super Contributor
timestamp: February 08, 2021, 02:57:30 pm
content: On serious side though, I'm very interested like the "behind the scene" thingy on this project.I guess it must be a complex task, as the work and responsibility spread across so many buildings, from management like dealing with different buildings owners, also others aspect like they're all not built & finished at the same time, down to nitty gritty of technical challenge like how they maintain the LED displays that have brightness, contrast and density so evenly spreaded, the power, management and billing and etc for running this.Its quite dizzying for me personally to even think about it. Wish there will be a coverage/documentation on this kind of project, must be interesting.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: February 08, 2021, 09:08:31 pm
content: America:The blueish light from LEDs worsens light pollution, which impacts astronomy, wildlife, and our own health.China: Hold my baijiu.
Mysterious NLDJ - Page 1
Forum section: electronics / general

author: Vytautas
author_rank: Regular Contributor
timestamp: February 07, 2021, 06:48:39 pm
content: Hello, guys,Can someone help me with figuring out what is the SOT-23-5 component marked NLDJ in the board (two of them on the board)? It is used in a battery free guitar pickup (the large white circles are the places for the 5V supercaps which I removed trying to fix the thing). I have searched the net for this marking, no results.

author: tom66
author_rank: Super Contributor
timestamp: February 07, 2021, 10:48:29 pm
content: Given the use in the circuit and the number of passives, it's probably an op-amp of some kind. The pinout seems to be similar to SOT23-5 single channel opamps like MCP6001, but it's a bit odd given "ground" comes in via a track (maybe it uses a split supply?)

author: Vytautas
author_rank: Regular Contributor
timestamp: February 07, 2021, 11:35:21 pm
content: Thank you very much.My best bet is also an op-amp. It seems it is the MCP6401T-E/OT one.I will try to order and see.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: February 08, 2021, 12:14:31 am
content: Off-topic, but in looking for answer I learned that the SOT23 package was conceived in...1966 (the year I was born) and first produced in 1969. Yet, for another 10 years, the TV repair man still showed up with a van load of vacuum tubes...https://efficiencywins.nexperia.com/innovation/sot23-50-years-surface-mount-innovation-in-one-package.html
Trying to understand power company's 'fixed charges' - Page 1
Forum section: electronics / general

author: Raj
author_rank: Frequent Contributor
timestamp: February 07, 2021, 10:39:12 am
content: I was never interested in power company's fixed charges, until I saw my friend's electricity bill.He's been paying fixed charges, about 6 times more than what I pay.His electrical system is capable of 10Kw, while mine is 2Kw capable.I don't understand the reasoning and units that are using to charge us fixed interest.Can someone please explain what's going on here?Attached, screenshot of offending portion of the billsI think, load is max kW, the meter can supply, and bill period is no of days between bills but I can't understand the rate/ kW/ month thing.kW/month sounds like change in electricity consumption which is redicolously absurd.

author: tom66
author_rank: Super Contributor
timestamp: February 07, 2021, 11:21:41 am
content: At a guess, rate/kW/month is the cost the energy supplier charges (in INR?) per kW of supply capacity, per month you have that supplied.So since your friend has an 8.79kW supply, and the rate cost is 75 INR per kW per month, they pay a monthly cost of 659.25 INR. But, they are billed only every 60 days, so you pay approximately twice that (they approximate the year as having 366 days) but once every 60 days. That's what the (a*b*c*12)/366 is working out.It looks like the rate per kW increases with higher supply, probably because it costs incrementally more to supply a bigger supply line, and it's more likely (especially in India) that will be used continuously for things like air conditioning which requires higher downstream rating costing the power company more money.

author: Raj
author_rank: Frequent Contributor
timestamp: February 07, 2021, 11:27:03 am
content: Makes sense now. Thanks.
Tequipment code? - Page 1
Forum section: electronics / general

author: IDEngineer
author_rank: Super Contributor
timestamp: January 14, 2021, 03:37:11 am
content: Power outage here for the last 12+ hours, can only access the site via cellphone. A friend wants to buy a Hakko FR-301 and I'd like to help him with the Tequipment discount. Can someone point me in the right direction? Thanks!

author: SVFeingold
author_rank: Frequent Contributor
timestamp: January 14, 2021, 04:48:49 am
content: I think you have to contact them (ask for a quote) and mention EEVBlog. That's how I've done it. Not sure if there's an actual code.

author: IDEngineer
author_rank: Super Contributor
timestamp: January 14, 2021, 05:02:56 am
content: There at least used to be an actual code. I used it myself when buying lots of things. But I think it changes periodically and it's been a while.

author: MarkF
author_rank: Super Contributor
timestamp: January 14, 2021, 12:59:12 pm
content: There is a thread for the discount code. I used the code myself.At one time you had to request the code via a PM.However, tEquipment posted the actual code in the mentioned thread.I don't have a link for it. Just search the EEVblog forum.There is also a thread and discount code forSaelig.

author: IDEngineer
author_rank: Super Contributor
timestamp: January 14, 2021, 05:13:21 pm
content: Hard to search using only a cellphone.I'm now hotspotting through my cellphone. Latest code I can find here doesn't work (I just tried it). It ends in "6".Power is still out here. I'd appreciate a PM or something if anyone is willing to help.Thanks!

author: MarkF
author_rank: Super Contributor
timestamp: January 15, 2021, 08:13:29 am
content: That's the old code then.Try searching backwards from the end of the thread.tEquipment themselves posted a new code.

author: IDEngineer
author_rank: Super Contributor
timestamp: January 15, 2021, 10:51:22 pm
content: A nice member here PM'd me the reference, thanks. Works perfectly.Power has been restored here too, so we're digging our way back out of the mess. No hardline Internet yet, so this is via my laptop hotspotting through my cellphone which is propped in the window for better RF.Our production facility just got power back this morning after being offline for two days. There are still areas which may not be repowered until sometime this weekend.Normally I'm a huge RTFM guy and hate asking others to do what I can normally do for myself, but I was in a bind here with no power, no normal Internet, and very limited resources. My thanks again to the member who PM'd me the code, that got the ball rolling for us!

author: riyadh144
author_rank: Unknown
timestamp: February 07, 2021, 07:17:36 am
content: I really cannot find the original thread. Where did it go?Can some one please PM me the the code? Thanks
Running a NEMA 8 stepper at 6500rpm (and maybe kill yourself in the process.) - Page 1
Forum section: electronics / general

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: February 05, 2021, 11:51:47 pm
content: Just a friendly reminder that you can run a stepper at stupid speeds, if you just slowly ramp it up.I just ran a tiny NEMA 8 at 22kHz step speed (corresponds to 6600 rpm @200 steps per turn).I have no doubt i could go a lot faster, but I am scared the FR4 will snap and I will end up bleeding to to death on my workshop floor with a piece of PCB sticking out of my neck.

author: amyk
author_rank: Super Contributor
timestamp: February 06, 2021, 02:29:57 am
content: At those speeds it's no longer "stepping", but just running like a brushless motor with an insanely high number of poles.

author: ebastler
author_rank: Super Contributor
timestamp: February 06, 2021, 08:33:44 am
content: Quote from: BreakingOhmsLaw on February 05, 2021, 11:51:47 pmProvided you don't need any torque, of course.

author: james_s
author_rank: Super Contributor
timestamp: February 06, 2021, 08:46:40 am
content: I knew someone who did that about 20 years ago with one of those little steppers like the sort that used to be in floppy drives and printers. I think he had to give the 12V motor over 100V to overcome the inductance once it got up to speed.

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: February 06, 2021, 09:05:11 am
content: Actually, the speed signal correlates perfectly with the stepping speed. The challenge is to increase the speed at a rate where the motor can follow.If the axle goes out of sync for more than 0,5 degrees, you end up braking the motor instead of accelerating it.The secret sauce here is: you need a good speed signal. The trick I used here: The rotor (this is a field mill if you haven't guessed already) is made of PCB with a black solder mask. Underneath are two small strips without solder mask, narrow enough that it only triggers the speed signal in a single step position (see image below). That way the software can easily tell the phase shift of the rotor versus the step speed. You can even "catch" it again after losing sync without needing to start from zero. It's all software in the end.Steppers are usually not made for these speeds, they have the wrong type of bearings. They are made for torque, not speed. But if you need it to go fast, this is the best approach. Doesn't even get hot, i run it with just 9V / 85mA.I will probably make the motor current software controllable in the final board, to get more torque at low speeds and decrease current once it hits target speed to decrease noise.Have a nice day!EDIT: inserted image
Working from your 'car' - Nissan office pod - Page 1
Forum section: electronics / general

author: DrG
author_rank: Super Contributor
timestamp: February 05, 2021, 06:59:17 pm
content: https://www.cnn.com/style/article/nissan-concept-office-pod/index.html

author: georges80
author_rank: Frequent Contributor
timestamp: February 05, 2021, 10:29:52 pm
content: I guess you just hang off the back when you need to take a dump etc...I need to find a job where I get paid for concept engineering, much easier than having to actually make something usefulcheers,george.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: February 05, 2021, 10:33:21 pm
content: Looks like a solution looking for a problem.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: February 05, 2021, 10:37:01 pm
content: This is the other model they offer.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: February 05, 2021, 10:50:49 pm
content: Quote from: Homer J Simpson on February 05, 2021, 10:37:01 pmThat's a bit of a contentious issue in my city at the moment..https://www.smh.com.au/national/nsw/woman-found-in-car-boot-with-stab-wounds-two-women-arrested-20210203-p56z6l.html

author: DrG
author_rank: Super Contributor
timestamp: February 06, 2021, 12:31:03 am
content: Quote from: Ed.Kloonk on February 05, 2021, 10:50:49 pmAus=US?In US a BOOT, with regard to an auto looks like thisNot sure Nissan has any plans for adopting this model.https://www.dailymail.co.uk/video/news/video-1545425/Aussie-bloke-s-ingenious-invention-turns-ute-bar-wheels.html

author: DrG
author_rank: Super Contributor
timestamp: February 06, 2021, 12:33:15 am
content: Quote from: georges80 on February 05, 2021, 10:29:52 pmThat's a special option...available soon.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: February 06, 2021, 12:33:45 am
content: Quote from: DrG on February 06, 2021, 12:31:03 amA long time ago we used to place a bottle cap on the dash and find a road with a sweeping bend and have a competition who could go the fastest without the bottle cap moving.
Starship SN9 flight test in < 30 minutes (disclaimer here) - Page 1
Forum section: electronics / general

author: mrflibble
author_rank: Super Contributor
timestamp: February 02, 2021, 07:33:41 pm
content: For those interested:https://youtu.be/wfHqbahPKpY

author: wraper
author_rank: Unknown
timestamp: February 02, 2021, 07:42:08 pm
content: Also from another "spy".

author: wraper
author_rank: Unknown
timestamp: February 02, 2021, 08:32:52 pm
content: RUD

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: February 02, 2021, 08:34:52 pm
content: Crash and burn!

author: tom66
author_rank: Super Contributor
timestamp: February 02, 2021, 08:48:26 pm
content: Looks like only one engine lit, one tried to start but quickly extinguished. Insufficient thrust and an unscheduled disassembly follows.

author: Gyro
author_rank: Super Contributor
timestamp: February 02, 2021, 08:49:43 pm
content: At least it didn't land on SN10.

author: Neilm
author_rank: Super Contributor
timestamp: February 03, 2021, 06:56:49 pm
content: What gets me is that it looks as if it over rotated, where as SN8 was vertical at h=0

author: raptor1956
author_rank: Frequent Contributor
timestamp: February 04, 2021, 01:25:42 am
content: Not only did one engine not light fully there appears to be a couple pieces fly off from the bottom. Interesting that Elon has not responded about SN9 as he did almost immediately after SN8. Given the high energy of the crash and the proximity of SN10 it would highly surprise me if SN10 wasn't damaged. The damage may be minor and fixable but it could be worse -- that's the risk you take when you try to land so close to critical items. The thing I am truly impressed by is the precision of the navigation as both SN8 and SN9 crash on the landing pad.Brian

author: TerraHertz
author_rank: Super Contributor
timestamp: February 05, 2021, 05:06:33 am
content: Maybe it might be a good idea to flip it to vertical a couple of seconds earlier, and let the fuel settle in the tanks and pipework before trying to light all the engines?Setting up the next ready ship on a pad so close by the testlandingimpact point, does seem a bit overconfident.

author: Neilm
author_rank: Super Contributor
timestamp: February 05, 2021, 05:52:45 pm
content: Quote from: TerraHertz on February 05, 2021, 05:06:33 amThe fuel is under a lot of presure in the tanks. Current speculation I have heard is that it was caused by an igniter issue. Raptor uses igniters (basically arc welders) rather than TEATEB and they have proved to be tricky to get working. I believe there are three, one in the main engine and one in each of the preburners that drive the pumps. Several static fire attempts have aborted due to them not working correctly.
Tianwen-1 Mars exploration probe approaching the orbit - Page 1
Forum section: electronics / general

author: BravoV
author_rank: Super Contributor
timestamp: February 06, 2021, 11:13:11 am
content: China's Tianwen-1 Mars probe sent back its first image of Mars.It has traveled about 465 million kilometers, reaching more than 184 million kilometers from earth and 1.1 million kilometers from Mars as of 8 pm Friday.And will enter Mars orbit on 10th Feb 2021.Source ->China's Tianwen-1 Mars probe sent back first image of Mars

author: ataradov
author_rank: Super Contributor
timestamp: February 06, 2021, 07:06:15 pm
content: This is an interesting month for Mars exploration. NASA's Mars Perseverance rover will land on Feb. 18 too.

author: rdl
author_rank: Super Contributor
timestamp: February 06, 2021, 11:59:15 pm
content: For those who are not space nerds, approximately every 26 months the orbits of Earth and Mars align just right for minimum energy transfer orbits. That's why all the space programs rush for Mars around the same time. Mars has a history of being a difficult target to reach. I wish the Chinese and everyone else good fortune in their attempts this time around.https://en.wikipedia.org/wiki/Hohmann_transfer_orbithttps://en.wikipedia.org/wiki/Mars_launch_window

author: BravoV
author_rank: Super Contributor
timestamp: February 07, 2021, 07:32:13 am
content: Quote from: ataradov on February 06, 2021, 07:06:15 pmIndeed, interesting time as we have 3 nations probes on their way to Mars, 2 landers (US & China) and 1 orbiter (UAE).
Tools to design LED grow lights. - Page 1
Forum section: electronics / general

author: pisoiu
author_rank: Regular Contributor
timestamp: February 05, 2021, 11:20:02 am
content: Hi all,Currently I am experimenting with some LED grow lights because I want to create a solution for vertical farms in the future, if it will make economical sense. But in the process of designing LED panels, I lack some knowledge, therefore I ask for some help, if possible.The panels I designed uses low power LEDs to make things easier with thermal management. For now I have 5 panels to test with, they have blue, red, lime and infrared LEDs, the LEDs are dedicated for horticultural applications. Each panel have near 1000 leds. The power supply is also designed by me because I want to be able to change the intensity for each wavelength independently.There are 2 main issues in this project which needs to be solved. One is the panel itself, to test it, make it work under all working conditions, to ensure quantity and quality of output light. The other one is using this panel, to make tests on various crops, I already have a hydroponic setup for this.In order to be able to correctly measure the output from the panels, I use a PAR meter from Apogee Instruments, SQ626, it works on extended range, from 340 to 1040nm. But this gives me only quantitative indication, so for quality of light I will have to purchase a spectroradiometer. Those coming from big names in industry are too expensive for me, but I can afford a model I found on aliexpress, is around $1100.https://www.aliexpress.com/item/10000015842704.html?spm=a2g0o.cart.0.0.6f173c00FIg70G&mp=1Unfortunately I know nothing about this brand and there are not many customers of this tool sharing their experiences on the web.Finally, my problems: in order to change the light output for my leds I use a TPS92513 driver. Output is controlled with a PWM signal of approx. 200Hz. I am not familiar with exactly how a PAR meter or a spectroradiometer are internally built (especially on the ADC section) and I do not know if, for a proper measurement, they require constant light over the sensor and if the measurements are not tricked by PWM modulation. I asked Apogee instruments about that, no answer so far and I also asked chinese manufacturer, but of course they sent me a reply which indicated they did not understand a bit from what I asked. I would like, of course, to avoid spending 1k$ on a tool which is not able to measure correctly PWM modulated light.
does anyone know how to xfer google authenticator to a new phone if its an old v - Page 1
Forum section: electronics / general

author: Beamin
author_rank: Super Contributor
timestamp: January 30, 2021, 01:21:41 am
content: I went from an Iphone 7 to a 10max. I need authentication for my new phone. The version on my new phone has an option to Xfer, but the iphone 7 seems to be an older version that doesnt have an option to xfer out only in. So if I want to use my coin base I have to have my old phone connected to the internet. Does anyone know how to email google tech support? I have been trying to fix this for hours and getting quite frustrated. Or is there a way for coinbase to generate a new QR code I can scan in my authenticator? I read all the articles on coinbase and sent multiple emails but Im still waiting to hear back about issues from last month for support tickets I created so their cust support is useless I think they are flooded with emails and have reduced staff thanks to covid.I know its a bit off topic but im so sick of dealing with this.

author: PlainName
author_rank: Super Contributor
timestamp: February 01, 2021, 06:57:58 pm
content: Can't help you, sorry, but I learned early on to keep a separate copy of the key used to set an entry. Also, I replicate Authenticator entries to the open source 'andOTP' (also available on the playstore) which kindly allows access to the keys at any time. That ensures that a) I have at least two different backup sources for the keys, and b) I know a key hasn't locked me into a specific app.

author: Beamin
author_rank: Super Contributor
timestamp: February 05, 2021, 03:50:36 am
content: Quote from: dunkemhigh on February 01, 2021, 06:57:58 pmI ended up using microsoft auth. andOTP will just grab the codes? EDIT andotp seems an android only thing. I wish we didnt have a "phone war" like vhs vs beta, I use apple because it works with low vision but I cant do half the cool stuff because my family has androids. Which are better but im locked into apple, I must say I am impressed with the 10Max how you can tap the back of it to control the front. Touch sensitive glass on back and front plus facial unlock is really cool. I wonder if it wirelessly charges I hope so.

author: PlainName
author_rank: Super Contributor
timestamp: February 05, 2021, 05:14:33 am
content: QuoteAh, sorry, didn't realise the 10max was still iPhone - thought you'd jumped shipThere's a Windows equivalent too, but I guess that's not good if you're on a Mac (unless, parallels):https://winauth.github.io/winauth/index.htmlQuoteDon't know enough about iPhone to know what it does in that line, but Android will let you increase the size of display objects to assist with that.
Do we want to embrace home auto as a forum? - Page 1
Forum section: electronics / general

author: paulca
author_rank: Super Contributor
timestamp: February 06, 2021, 09:20:49 pm
content: Can we add... Do we want to add a "Home Automation" dedicated topic on the board?Looking at the current topic it kind of spans about 4 or 5 topics, probably more.MicrocontrollersRenewablesBeginnersRF (sometimes)Robotics&Auto <- could this be renamed to be more suitably appealing?Embedded?Networking/WirelessBeerAlways beer.

author: Ranayna
author_rank: Super Contributor
timestamp: February 06, 2021, 11:23:37 pm
content: Maybe put that into the new catergory at the bottom, that somehow noone talks about? :p I think just the 3D Printing thread is currently really active there, i have *no* idea why that had to be delegated to the very bottom of the forum...
Thunderstorm phenomena - Page 1
Forum section: electronics / general

author: innkeeper
author_rank: Unknown
timestamp: February 04, 2021, 07:03:54 am
content: Many many years ago, (too many years ago lol ) when I was in my early teens, we were vising a relative house that had a big flat pane glass front window. At the time i was deep into electronics as a hobby, but had no formal lt training yet, but knew enough to be tackling small projects and had released my share of magic smoke from componentsThere was a thunderstorm nearby, and as my brother and i looked through the glass we could see what appeared to be wiggling lines of what i can only describe as very thin glowing lines, like little lightning bolts but were continually dancing there. as I moved you could see they were coming from specific points in the lawn and not something in the glass itself. if we opened the door and looked outside we could not see them. they could only be seen through the glass. it was puzzling then and even to this day. once the storm had passed they were gone.I do recall looking at the glass itself, it did have a slight tint to it, and also was double pane, and could have had some kind of gas in it like argon, this was in the 70'sI've since learned about what is called feelers during thunderstorms, and am pretty sure that's what I was seeing or something closely related. but I am puzzled why I could see them through the pane glass and not directly.I've not seen this phenomenon since.anyone else see such things and any ideas on why it could be seen through the pane of glass but not directly?
Inductor/Electromagnet used to lift up a magnet? Joules to Newtons or Joules to  - Page 1
Forum section: electronics / general

author: renzoms
author_rank: Regular Contributor
timestamp: February 03, 2021, 02:22:53 am
content: With interest in using an electromagnet to lift up a magnet.I dove in. I will state general information. The set up is unknown but I'm interested in the physics/electrical engineering involved in calculating the amount of ______ needed to lift up a mass (magnet with magnetic strength x).I reviewed "electromagnets". I see an inductor produces a magnetic field, a summation of the contributions of electrons and we get some equations.Regarding inductors, Energy is .5LI². We can adjust the power/energy/magnetic flux in an inductor by varying the voltage/current/turns, etc.Also since V = dϕ/dt, maybe we can integrate velocity to find the magnetic flux or something but idk if magnetic flux is relevant to lifting a magnet on the ground.So I found a link to the an equation expressing the force between two magnets in Newtons homework and exercises - calculate force between two magnets - Physics Stack ExchangeI see magnetic force is measured in Gauss.I've nearly finished relearning Classical Mechanics, so I'm thinking about using F = ma, and I'm not sure how the inductor/"electromagnet" ties into this nicely.I don't know how to convert an inductors properties into Gauss, nor express it as a function of distance, and I think you guys can help!I considered using F = kqq/R or some other attraction law, but still idk how to relate an inductor and it's Joules or other properties to "magnetic strength" I can use in a kinematics analysis.
Why is a LR-700 AC resistance bridge showing negative resistance? - Page 1
Forum section: electronics / general

author: geoyumzzz
author_rank: Newbie
timestamp: February 02, 2021, 10:24:58 pm
content: I have a Linear research Inc. model LR-700 AC resistance bridge which is the benchmark for resistance measurements. However, for some reason, the metallic thin film sample that I am currently measuring is showing a negative resistance.Some more detail, even though I don't believe the sample has any inductance, the LR-700 measures about -400 Kohm reactance (mutual inductance). This -400kohm reactance is measured in the resistance range of 2 Mohm. I believe that the resistance range is coupled for measuring both the resistance and the reactance. Hence, the lowest measurable resistance in the 2Mohm range is 10Kohm. I observe that the resistance value goes negative after reaching this value of 10Kohm, which might mean that the resistance value is out-of-range, but since the reactance value is still in the 2Mohm range, the range remains at 2Mohm. I am unable to find any information about the negative resistance measured by a LR-700 AC resistance bridge. I am wondering if anyone has also encountered a similar problem or figured out how to interpret a negative resistance measured. I would be immensely grateful if someone can help me understand this. Thank you.

author: bdunham7
author_rank: Super Contributor
timestamp: February 02, 2021, 11:05:53 pm
content: Do you have the manual? (Just asking...)Does the unit appear to work properly with other resistive samples?Exactly how is the thin film sample mounted and connected to the bridge? Is there any chance that the sample (as connected) is capacitive or has capacitance to ground?
[English] Antonym for prime as a verb - Page 1
Forum section: electronics / general

author: blueskull
author_rank: Unknown
timestamp: February 02, 2021, 06:38:11 am
content: As the title suggests, what is the antonym of prime as a verb? I did try to look up online, not to find an appropriate one.Use case:Prime the laser by enabling its master oscillator (aka seed laser).I want something like:___ the laser by disabling its master oscillator (aka seed laser).Any suggestions on what should I put in the blank?

author: helius
author_rank: Super Contributor
timestamp: February 02, 2021, 06:50:37 am
content: Not "composite"?A common pair of verbs is "arm/disarm". But priming for lasers may be not the same as this.Perhaps the word could be "quench"?

author: ataradov
author_rank: Super Contributor
timestamp: February 02, 2021, 07:06:08 am
content: "Inhibit" probably.

author: sleemanj
author_rank: Super Contributor
timestamp: February 02, 2021, 07:54:28 am
content: Inhibit, discharge, deactivate, drain, clear, disable, reset...There is no direct opposite for "prime" in the sense of "preparing something for something else to be done", it can mean different things in the forward direction let alone the reverse.
Terrible description of vacuum tubes.  - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: February 02, 2021, 04:58:56 am
content: On the RS website I found this dreadful explanation of what vacuum tubes / valves are all about. For example:Quotehttps://au.rs-online.com/web/c/semiconductors/discrete-semiconductors/vacuum-tubes/Dear oh dear...

author: helius
author_rank: Super Contributor
timestamp: February 02, 2021, 06:35:08 am
content: That reads like auto-translated gibberish.Does RS actually sell tubes? They are made in small numbers but I am surprised that they would be stocked by any distributor.They are not properly categorized as "semiconductors": the vacuum inside the glass is not a semiconductor, it has no band gap. These are vacuum-state devices similar in some ways to gas-state devices such as thyratrons, neon tubes, etc.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 02, 2021, 07:21:54 am
content: Honestly I'm more impressed that they went to the trouble of ordering them with house branding.Quote from: helius on February 02, 2021, 06:35:08 amOr physically speaking, whereas a FET has charge carriers in the conduction or valence band (either side of the band gap), a vacuum tube merely promotes charge carriers further, into the free / unbound / vacuum state band. The major operational differences are: ballistic transport (no ions to weigh* down the charge carriers), operation exclusively with electrons (you can't make holes in vacuum, not without them annihilating with regular electrons anyway -- or without using plasma physics to prepare naked, and far far heavier, protons), and much lower current densities due to the lack of charge balance, again due to the lack of ions.(*Not just in terms of collision (friction, diffusion/drift transport), but literally, the effective mass of an electron is something like 100x higher in typical cases. Crystals, being periodic structures, have an effect something like a waveguide, where the group and phase velocity can be all weird compared to the free particle case. Ballistic transport is sometimes possible in semiconductors, for example GaAs has high enough... mobility, is it due to? -- where there's a small operating band above saturation velocity yet below avalanche (impact ionization) threshold. Hence Gunn diodes, which are actually monodes -- a uniformly doped bar of semiconductor that sings when you make it sweat hard enough!)Tim
Interesting chat with Sandy Munro and Elon Musk - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 02, 2021, 06:56:45 pm
content: How many other big company CEOs know this much detail about their products. And he also does rockets...https://youtu.be/YAtLTLiqNwg

author: benst
author_rank: Regular Contributor
timestamp: February 03, 2021, 12:49:20 am
content: Quote from: mikeselectricstuff on February 02, 2021, 06:56:45 pmNot many, I'm sure. Tory Bruno from ULA is pretty good too. SmarterEveryday has a couple of interviews with him:Ben

author: bw2341
author_rank: Regular Contributor
timestamp: February 05, 2021, 02:47:58 am
content: I don't know if there is wide interest, but here is a series of videos going in depth about what Tesla has announced on battery day. Nine parts so far with more to come. The creator of The Limiting Factor youtube channel, Jordan Giesige, has put a lot of research into making these videos, finding published research and interviewing people working on batteries.The shallowest summary of the video series is that Tesla is working very hard and as quickly as possible to bring multiple near-term advances in battery technology to production. Dave's video on the Tesla 4680 battery format covers just one small aspect of what Tesla is working on.
Were metal-can transistor pin spacings originally based on tube pinouts? - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 31, 2021, 12:00:03 am
content: Idly playing with my tube pin straightener, I was curious to see if I could use it on a 4-pin TO-3 package one pin at a time. Much to my surprise, it fit the 9-pin Noval socket on my pin straightener.Weird. Ya think JEDEC still had some JETEC diagrams lying around and just reused them?

author: amyk
author_rank: Super Contributor
timestamp: January 31, 2021, 02:50:09 am
content: http://www.interfacebus.com/semiconductor-transistor-packages-4-pin-TO-3-flange-mount.htmlhttps://w140.com/tekwiki/images/0/06/B9A_base.gifThey are definitely almost exactly the same.
Help me to understand the right way to place thermistor and fuse for ac circuit - Page 1
Forum section: electronics / general

author: radhika
author_rank: Regular Contributor
timestamp: January 25, 2021, 03:31:32 pm
content: Greetings, I am working on 220V AC to 12V 10A DC SMPS circuit design. For reference I am usinghttp://danyk.cz/reverz44_en.htmlthis circuit.I am using UC3842 IC for switching. But, I am unable to understand the placement of fuse and thermistor. In some/few circuit of SMPS, fuse and thermistor connected in series, in other circuit fuse connected first and later thermistor connected after choke inductor.Please help me to undetand the behaviour and functioning of these two, thermistor and fuse in series as well as parallel.Thanks

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 30, 2021, 07:37:25 pm
content: It does not matter on which part of the circuit to install the thermistor, the current in the entire circuit is the same. The thermistor is used to limit the charging current of the smoothing capacitor in the rectifier. But it is good practice not to break the zero power wire. On the specified circuit, the fuse is placed unsightly, it must be transferred to the phase wire.
Can you identify this antenna? - Page 1
Forum section: electronics / general

author: vlad777
author_rank: Frequent Contributor
timestamp: January 26, 2021, 02:40:18 pm
content: Can you please tell me the manufacturer behind this logo?And what kind of antenna is this?Many thanks!

author: geggi1
author_rank: Frequent Contributor
timestamp: January 26, 2021, 08:48:49 pm
content: Its som kind of panel antenna.Most likely a phased array of patch antennas that is very common on frequencies above 1Ghz like wifi and mobile phone.The antenna is probably made in China like most consumer grade stuff.

author: vlad777
author_rank: Frequent Contributor
timestamp: January 30, 2021, 04:29:02 pm
content: Cambium Networks ePMP 5 GHz Force 180 Integrated Radio - 16 dBi Patch Antennahttps://www.amazon.com/Cambium-Networks-Force-Integrated-Radio/dp/B006QY3ML8
Looking for a tool like a scalpel but with no sharp edge - Page 1
Forum section: electronics / general

author: ivan747
author_rank: Super Contributor
timestamp: January 30, 2021, 02:00:56 am
content: I’m working at a manufacturing plant and the health and safety guys want to take away all scalpels. I don’t really need our scalpels to be sharp, but the operators are complaining because the spatula I gave them is way too cumbersome. We use scalpels to scrape excess glue off the housings on our product. Using a dull blade doesn’t impact the job. Ideally I just want to buy a small attachment for the scalpel base that comes dull from the factory, kind of like a metal spatula sort of edge, but much smaller, to it can be handled like a scalpel not like a spatula.Any tools come to mind?

author: bdunham7
author_rank: Super Contributor
timestamp: January 30, 2021, 02:05:45 am
content: https://www.micromark.com/Mini-Scrapers-Set-Of-4

author: Halcyon
author_rank: Unknown
timestamp: January 30, 2021, 02:06:32 am
content: Something like this:https://australia.ifixit.com/products/prying-and-opening-tool-assortmentor this:https://australia.ifixit.com/products/jimmy

author: themadhippy
author_rank: Super Contributor
timestamp: January 30, 2021, 02:20:24 am
content: coming at it from a different angle,cut proof gloves?also protects the workers from getting "dangerous" glue on there hands

author: DrG
author_rank: Super Contributor
timestamp: January 30, 2021, 02:41:54 am
content: There are a variety of laboratory grade stainless steel "micro" spatulas. I am adding "micro" to distinguish them from kitchen spatulas. These are all along the size of a scalpel,https://labsociety.com/lab-equipment/spatula-metal/Many different styles including some with thick edges that might work well for scraping (unless this is what you already tried); searching on "laboratory spatula" might find something suitable.

author: gnuarm
author_rank: Super Contributor
timestamp: January 30, 2021, 02:42:42 am
content: Is that for real that someone said the children can't have scalpels? I guess school children shouldn't have scalpels really. What? You aren't hiring 12 year olds???Who is health and safety exactly? I get this is what? a UK thing? I thought this is the sort of stuff you guys left the EU to get away from. That would never happen here in the good ol' US of A, fer sure!!!WHAT!!!!??? You are IN the US? It must be those commies!!! Where are they? Let me at 'em!!!

author: Bud
author_rank: Super Contributor
timestamp: January 30, 2021, 02:58:13 am
content: "Manicure spatula" at AmazonYou are welcome.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: January 30, 2021, 03:06:52 am
content: Also have a look for wax carving tool sets.
This laser etching attempt made me laugh. - Page 1
Forum section: electronics / general

author: darky8
author_rank: Contributor
timestamp: January 27, 2021, 05:04:33 pm
content: Hi Folks,Dave and everyone is always on about people trying to etch model numbers off ICs, usually when it obvious what it is.This is an attempt I found in my Lightwave RF dimmer switch! They've clearly set this up to do it as wellCan you identify it..?

author: GlennSprigg
author_rank: Super Contributor
timestamp: January 28, 2021, 01:18:45 pm
content: Lick & Rub !!!It soon comes off!!!I always wonder what 'process' they use to also write on the rubbery buttons of our typical remote-controls... There are buttons that we press/rub-on countless times a day, for countless months, andthe writing stays intact!!

author: amyk
author_rank: Super Contributor
timestamp: January 29, 2021, 01:32:58 am
content: MDT10Pxxx? An obscure microcontroller.

author: gnuarm
author_rank: Super Contributor
timestamp: January 29, 2021, 04:12:51 am
content: Quote from: GlennSprigg on January 28, 2021, 01:18:45 pmThe buttons on the old HP calculators could not be filed off. That's because they were "double injection molded" meaning they molded the buttons with numbers protruding and then molded more button around the numbers so the numbers went all the way through the button! Well... part of the way through anyhow. The point is they were not on top of the button, but within and so can't be rubbed off, ever.
Need some PLCC socket/chip testing tips - Page 1
Forum section: electronics / general

author: skysurf76
author_rank: Regular Contributor
timestamp: January 31, 2021, 01:44:59 am
content: I need to monitor some signals on a chip in a 44 pin PLCC socket and I was wondering if there is enough room between the socket connectors and the chip pins to insert a small wire as a test lead? I was wondering if anyone had any experience with this, and if so any other tips and trips would be GREATLY appreciated.Thanks!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 31, 2021, 02:41:02 am
content: That's old stuff. On the sockets I've seen there is an opening next to each socket pin where you can jam a small piece of solid wire to access the signal. Don't touch the pins of the PLCC itself, they have a habit of squishing inwards and then not making contact properly with the socket.In other words jam a piece of wire between the body of the socket and the contact of the socket in the "pocket". It's convenient.I don't think you can break out all the signals that way though, it's not terrible solid IME.

author: PlainName
author_rank: Super Contributor
timestamp: February 01, 2021, 04:21:17 pm
content: The simplest way to do it, money no object, is with something like the Winslow W9176 (crappy photo attached).If you like that kind of thing there is a catalogue full of them:Winslow catalog (25MB pdf)There are (much) cheaper clip-on breakouts if your chip is soldered on the board - you can probably replace the socket with a soldered chip if you don't need to remove it again. Although a quick blast from a hot air tool would get it off easy enough.

author: skysurf76
author_rank: Regular Contributor
timestamp: February 02, 2021, 01:37:56 am
content: Thanks so much Alex. Your post actually lead to the solution. While probing between the socket frame and socket pin with needle probes the test on the device passed that was failing previously. The pressure against the socket pins forced them to make good contact with the chip's pins. We are going to replace the socket.Dunkem, I was doing some searching and came across that, and it would have been the perfect solution, but unfortunately purchasing it would require several months in my situation. Good find though. It would have been my ideal solution.
Propellant-less electric spacecraft engine? - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: January 27, 2021, 01:32:03 pm
content: Don’t know whether this belongs in dodgy technology or not. It’s way beyond me.https://electricspacecraft.org/index.html

author: Refrigerator
author_rank: Super Contributor
timestamp: January 27, 2021, 03:35:02 pm
content: What's with their obsession with elephants?Edit: look out for the jumpscare on page 43

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: January 27, 2021, 04:34:37 pm
content: Sheesh. He seems to have a serious bee in his bonnet about PhDs. And he seem incapable of introducing this complex topic at an accessible level.I gave up after page 7 (except a quick scan for elephants) and a look at his patent claims which are a million miles from a functioning propulsion system.

author: bdunham7
author_rank: Super Contributor
timestamp: January 27, 2021, 04:40:47 pm
content: EmDrive was a widely-ridiculed concept until a NASA team announced that it appeared to work a little bit. That result has not been validated or replicated. This appears to be the same notion, repackaged.https://en.wikipedia.org/wiki/EmDrive

author: Syntax Error
author_rank: Frequent Contributor
timestamp: January 27, 2021, 11:49:29 pm
content: FYI, for space geeks and physics nuts, the Pioneer Anomaly is worth checking out as a form of 'free-energy' spacecraft deceleration.https://en.m.wikipedia.org/wiki/Pioneer_anomaly
How to find a schematic for zeny 853d 3n1 hot air rework station - Page 1
Forum section: electronics / general

author: genxtech
author_rank: Newbie
timestamp: August 15, 2019, 05:53:38 pm
content: How to find a schematic for zeny 853d 3n1 hot air rework station:Main board is youde853mdv5control board yd853sdv4Any takers have a knowledge base on where I would get my hands on these???Sincerely, all help GREATLY appreciated.

author: Civnicq
author_rank: Newbie
timestamp: December 18, 2019, 12:27:41 am
content: I would also like to know. Unless you could help me out. I have a resistor that is fried. I can't tell what color the bands are, and I can't see the ohms printed on the board because it was burned. Could you tell me what resistance is printed under the R33 resistor, please? Maybe I could help you with your problem as well.

author: amde76
author_rank: Newbie
timestamp: January 27, 2021, 07:22:49 pm
content: R33= 150 ohm/3W