hybridfree/eevblog-posts huggingface dataset:
What laser power to cut 1~1.5mm stainless steel ? - Page 1
Forum section: electronics / projects

author: alpher
author_rank: Frequent Contributor
timestamp: October 31, 2019, 03:47:28 pm
content: Intigued by recent thread about cutting square holes, I came to realise that it may be possible to join the 21 century and get the small cnc cutter from Aliexpress or such.The thing is I'd like to cut not only plastics like plexiglass etc. but also metal, stainless steel in particular.Machine doesn't need to be big, I think that 1' by 1' (30cm x 30cm for your metric afficionados), nor does have to be fast, I can waitBut it has to be able to cut through 20 to 18 gauge ss sheets (1 - 1.5mm), the sheets are designed for laser cutting as they're coated with special film, pic attached.My guess is that 100W co2 laser may be too weak, but again have no experience in the matter.Any input appreciated.Thanks.

author: MagicSmoker
author_rank: Super Contributor
timestamp: October 31, 2019, 04:08:38 pm
content: IIRC, the wavelength of fiber lasers (~1um) is better absorbed by most stainless steel alloys, but CO2 lasers produce a higher quality beam that can produce a smaller spot size despite having a 10x longer wavelength. In either case, you are probably looking at needing >1kW of raw beam power before focusing to reliably cut 1mm thick metal. Not really something that can be done at home, I'm afraid.

author: KaneTW
author_rank: Frequent Contributor
timestamp: October 31, 2019, 04:30:35 pm
content: You want a pulsed (Q-switch) laser for this application. It's doable at home if you know what you're doing.

author: alpher
author_rank: Frequent Contributor
timestamp: October 31, 2019, 04:54:18 pm
content: Sorry, I see I posted it in the wrong section, should be in manufacturing & assembly.We're not talking about "home" use here.Strictly business.

author: Kjelt
author_rank: Super Contributor
timestamp: October 31, 2019, 07:02:09 pm
content: 1kW CO2https://en.m.wikipedia.org/wiki/Laser_cutting
What ldo for battery project?  - Page 1
Forum section: electronics / projects

author: atgeek
author_rank: Contributor
timestamp: November 21, 2016, 01:39:00 am
content: I need a cheap ldo voltage regulator with low quiescent current for a battery powered project. The input should be in 5-12v range and the output is irrelevant if 5v or 3.3v. Do you know someone?

author: salbayeng
author_rank: Frequent Contributor
timestamp: November 21, 2016, 02:11:00 am
content: I use the TPS76050 (TPS76033 for 3,3v) , its 50mA out, Iq ~ 100uA.For nanopower applications you might want to look at some nanopower voltage references, many can supply 5v ~ 10mAOne thing to check on the data sheet is how the queiscent current (= ground leg current) changes with load, some parts may add 10% of the load current as quiescent.If you only want approximately 5v then consider using a depletion mode mosfet , the VGS is -1v so use a 4v low current, low leakage zener diode. The attached figure has a 10k resistor, so Iq = 100uA. A bigger resistor will mean less Iq at the expense of more temperature drift and worse regulation. With a BSP 149 expect 100mV regulation up to 20mA and < 100mV droput voltage.
What liquid flux to use with Bon Pen? - Page 1
Forum section: electronics / projects

author: zapta
author_rank: Super Contributor
timestamp: September 07, 2015, 03:58:46 pm
content: I ordered a Bon Pen and need to get liquid flux to fill it. What kind should I get, no clean? rosin? RMA? RA?So far I used the ChipQuik tacky no clean but it is too thick for the Bon Pen I presume. I also has a felt pen with Kester 981 and it kind of works but the flux feels weak.If I get a rosin based, what happens if I don't clean it perfectly, for example, under the components? Will it corrode and damage the board?This is for hobby use at home. My components are typically new, I use leaded solder and I clean with IPA. I want to have just one kind of flux, even if it is a compromise.

author: ConKbot
author_rank: Super Contributor
timestamp: September 07, 2015, 05:48:16 pm
content: RMA flux is good for applications where you might not be able to clean it. RA is a little too active/aggressive.

author: zapta
author_rank: Super Contributor
timestamp: September 07, 2015, 06:35:59 pm
content: Quote from: ConKbot on September 07, 2015, 05:48:16 pmDoes this look good? I need only a small quantity and this US seller seems to be legit.http://www.ebay.com/itm/141250481358
What Lithium cell chemistry to choose? - Page 1
Forum section: electronics / projects

author: Wilson__
author_rank: Frequent Contributor
timestamp: May 29, 2024, 05:10:02 pm
content: Whichlithium cell chemistry for mobile and wearabledevices is good for high energy, small size and weight, at50 to 100mAh:Occasionallyshort pulse(2 seconds or less) discharge at1C.Routine discharge 15mA for ms, once per hundreds of secondsWeeks to a few months per recharge.No need for fast recharge time.Price point is medium to high consumer electronics (seem price is not high for this small mAh).Searching shows that there are four major types:Lithium Cobalt Oxide(LiCoO2) — LCOLithium ion manganese oxide battery (LMO)Lithium nickel manganese cobalt oxides (abbreviated NMC, Li-NMC, LNMC, or NCMLithium iron phosphate battery (LiFePO 4 battery) or LFP battery (lithium ferrophosphate)Many thanks

author: thm_w
author_rank: Super Contributor
timestamp: May 30, 2024, 12:22:53 am
content: Have you calculated what space you have available and what energy density that works out to?Desired cycle life?LFP and LTO will be most reliable and safest, but will be most expensive and least energy dense. And could be harder to deal with due to the non-common voltage range.You can look up some commonly available parts and make comparisons:- Samsung galaxy watch 4 = 350mAh- Apple watch series 3 = 340mAh A1875- Fitbit luxe = 50mAh LSS271120P

author: amyk
author_rank: Super Contributor
timestamp: May 30, 2024, 01:33:20 am
content: Something like an LIR2050? Your application is not particularly demanding, and NMC is probably the most common and cheapest these days.

author: Wilson__
author_rank: Frequent Contributor
timestamp: May 30, 2024, 10:06:45 am
content: Many thanks. From web info, seem leading energy density per kg or volume are:LCO is 200Wh/kg. LMO 150LCO is 400Wh/litre, LMO 350Need to be compatiable with standard charging controller IC.
What low Iq LDO do you use? - Page 1
Forum section: electronics / projects

author: Mad ID
author_rank: Regular Contributor
timestamp: September 10, 2015, 12:53:35 pm
content: Hi,for my battery powered designs I usually use NCP4587 LDO from ON Semiconductor. It's a great LDO because it's quiescent current is only 1uA when the CPU is sleeping but can deliver great transient performance by adjusting it's ground current quickly.The problem is that it is very small and it's not suitable for some boards (SOT-23 version not easily available).Can you recommend a LDO which has very little ground current when the output current is low (<100uA) but can provide very good load transient on higher currents. In other words, the LDO should increase it's internal current on higher loads to provide performance and be ready for load steps.I find it difficult to find a LDO similar to NCP but in bigger package.Thanks

author: rvalente
author_rank: Frequent Contributor
timestamp: September 10, 2015, 01:41:30 pm
content: MCP1711 is available in SOT-223 as well, active current of 600nA...http://ww1.microchip.com/downloads/en/DeviceDoc/20005415A.pdfMC1700 you can get even in TO-92, SOT-89 and SOT-223 (or even DFN), the acitve current is bigger, 1.6uA.http://ww1.microchip.com/downloads/en/DeviceDoc/20001826C.pdfHave you check TI's parts?Sometimes I find myself in similar situations, I was looking for a boost buck converter, which would take one LiPo and output 3V3, lots and lots of parts available from all vendors, but they're all tiny tiny, probable smartphone market oriented.

author: Mad ID
author_rank: Regular Contributor
timestamp: September 10, 2015, 03:34:39 pm
content: Quote from: rvalente on September 10, 2015, 01:41:30 pmHeh, these regulators are very very slow. If I have any device which can draw 50mA in transient output voltage would drop which can reset the CPU and cause all kind of problems. That's why this is hardI want to avoid using two LDO, one for sleep and other during operation..

author: rvalente
author_rank: Frequent Contributor
timestamp: September 10, 2015, 03:41:41 pm
content: Hum, can't you fit one or two tantalum capacitor?

author: Mad ID
author_rank: Regular Contributor
timestamp: September 10, 2015, 03:45:51 pm
content: Quote from: rvalente on September 10, 2015, 03:41:41 pmIn a lot of cases no, that is why I'm searching for a good LDO.10uF should be enough to provide me with good transient response from 5 -> 50mA.

author: mikerj
author_rank: Super Contributor
timestamp: September 10, 2015, 03:50:06 pm
content: LP2981-N maybe?

author: Mad ID
author_rank: Regular Contributor
timestamp: September 10, 2015, 03:52:10 pm
content: Quote from: mikerj on September 10, 2015, 03:50:06 pm65uA Iq..not good

author: ralphd
author_rank: Frequent Contributor
timestamp: September 10, 2015, 07:46:37 pm
content: I have recently been looking for something similar. The xc6206(662k) is one I'm thinking of buying. Ive seen them even cheaper than the ams1117.http://www.torex-europe.com/products/range/120
What magnetics do I need connecting a SBC Ephy to local switch IC? - Page 1
Forum section: electronics / projects

author: Skavin
author_rank: Newbie
timestamp: June 08, 2023, 06:54:12 am
content: I would like to design a carrier board for a bunch of SBC's (NanoPi Duo2) and have them connect to a switch IC on the carrier board and have it present a single RJ45 on that so I can connect them all to my lab LAN at once.I am not hard set on a switch IC but but something like a RTL8305NB IC with 5 10/100 PHY ports.What magnetics do I need on the board between the NanoPi and the switch IC's inputs?If they were totally separate device's connected by cat5e there would be:Ephy <-> Transformer <-> common mode choke <-> auto transformer <-> RJ45 <-> cat5e <-> RJ45 <-> auto transformer <-> common mode choke <-> Transformer <-> Switch ICI assume that I can remove the cat5e and RJ45 connectors but how far can I go?Can they just be connected together as the grounds and so voltages should all be the same?Thank you in advance for any suggestions or pointers to more reading.

author: ajb
author_rank: Super Contributor
timestamp: June 08, 2023, 02:46:42 pm
content: Quote from: Skavin on June 08, 2023, 06:54:12 amWell, you'd really only have one transformer module with built-in chokes, generally, or a magjack, not three separate magnetic components for each PHY.It's possible to capacitively couple two PHYs instead of magnetically couple them. Note that this is not generally a great idea for ports that connect to the outside world. There are several appnotes on the idea, here's one:http://ww1.microchip.com/downloads/en/AppNotes/Capacitive%20Coupling%20Ethernet%20Transceivers%20without%20Using%20Transformers.pdf

author: Skavin
author_rank: Newbie
timestamp: June 09, 2023, 01:03:15 am
content: QuoteYes the transformer module has all 3 parts. My thought process was that 2 transformer modules back to back would be silly so what is inside them that is not needed and find surface mount devices that would do the job of what is needed. this path was bolstered by looking at the "HORACO 4 Port Gigabit POE Extender" from Aliexpress that I AssUMe works for some definition of works. It seems to just use a discreet center tapped transformer per pair for its PoE. attached is a board pic stolen from the the listings comments.QuoteThank you this is the information I was after. Documentation of how it should be done is much better than taking direction from a random piece of hardware from the internet. It has pointed me down a whole new line of investigation and reading. Who knows this old coder might make some hardware that works in his spare time
What might be the values of these heatsinks? - Page 1
Forum section: electronics / projects

author: nikkoderic
author_rank: Contributor
timestamp: May 15, 2016, 05:59:22 am
content: Hello community!I just want to ask what might be the thermal resistances of these old heatsinks. Doesn't have to be precise. I just want to know the ballpark values of these things. It would be very convenient to have an idea of what might be the thermal resistances of heatsinks with similar sizes without actually measuring them.The dimensions are as follows:Heatsink A: 25mm x 22mm x 15mm, AluminiumHeatsink B: 35mm x 15mm x 10mm, AluminiumHeatsink C: 30mm x 15mm x 8mm, I think it's copper.Thanks for your help! =D

author: danadak
author_rank: Super Contributor
timestamp: May 15, 2016, 09:45:12 am
content: Google this "heatsink size vs thermal resistance calculator",should help you estimate their performance.Regards, Dana.
What model of crystal - Page 1
Forum section: electronics / projects

author: Crystal-JU-206
author_rank: Newbie
timestamp: October 24, 2016, 03:57:28 am
content: Dear All,May I ask who knows what model of crystal generally used in bluetooth products, such as bluetooth USB adaptor, bluetoooth speaker, or bluetooth headphones ?TKS in advance!

author: Crystal-JU-206
author_rank: Newbie
timestamp: October 24, 2016, 06:28:06 am
content: Thank you so much

author: Crystal-JU-206
author_rank: Newbie
timestamp: October 28, 2016, 03:30:17 am
content: where can I find Crystal Resonator SMD3225?Do you know
What mosfet is this? - Page 1
Forum section: electronics / projects

author: Teza
author_rank: Contributor
timestamp: March 09, 2017, 05:12:53 pm
content: Have a mosfet, but are not sure about the correct manufacturer, so having problem to know what datasheet to read.It is labeled: IRF520 Y22W AH.Guess someone know the logo in the bottom left corner?

author: daveshah
author_rank: Unknown
timestamp: March 09, 2017, 05:16:58 pm
content: Pretty sure it's Siliconix - now Vishayhttp://www.vishay.com/docs/91017/91017.pdf

author: Teza
author_rank: Contributor
timestamp: March 09, 2017, 05:29:25 pm
content: Had some notes that said, VISHAY FORMERLY I.R. - IRF520PBF - MOSFET, N, 100V, 9.2A, TO-220, but did not know if this was for this mosfet.Then I know this is correct, thank you!
[Solved] What multimedia player for RTP protocol with manual SDP insertion? - Page 1
Forum section: electronics / projects

author: Yansi
author_rank: Super Contributor
timestamp: August 13, 2019, 08:18:57 pm
content: Hello,do you know of any multimedia player application (for Windows, preferably), that could play an RTP stream, but manually inserting the SDP data (stream parameters)?I thought of a well known VLC media player, the famous traffic cone, but it seams, that it is lost without RTSP. I do not want RTSP. For testing purposes, it'd be handy to have a player capable of receiving RTP data, while being able manually set the stream parameter (enter SDP descriptor) - i.e. entering the number of channels, sample rate, etc.The "payload type" field on its own in the RTP packet is not explicit enough for the RTP stream to be interpreted and played.Thank you for any hints & tips, how to debug a RTP streaming device.Y.

author: Marco
author_rank: Super Contributor
timestamp: August 13, 2019, 09:40:31 pm
content: Are you quite sure VLC can't simply open SDP extension files to load RTP streams?

author: Yansi
author_rank: Super Contributor
timestamp: August 13, 2019, 09:58:44 pm
content: Not sure at all. How would you open an "extension SDP file"?Imagine, I have a device producing (only) an RTP stream, with no other protocol containing the required SDP. So I need to constraint the stream manually, to be able to play it correctly (at all).//EDIT: Well, wait a moment: Will VLC eat a *.sdp text file from a local disk directly? That would probably help a lot too!

author: Yansi
author_rank: Super Contributor
timestamp: August 15, 2019, 06:52:39 pm
content: Ok! I have verified, VLC can eat and play a stream constrained using SDP file.I have put just this into a text file with SDP extension:Code:v=0c=IN IP4 239.0.0.1m=audio 5004 RTP/AVP 10This works great, however what doesn't is the VLC streaming function itself. When testing an RTP audio stream (payload type 10, the "L16 Stereo 44100Hz" using the VLC's "Audio-CD" streaming profile), VLC produces a stream with a LOT OF missing packets.The resulting audio (when received) was sounding very choppy with occasional longer pauses (hundreds of ms of data missing). Investigation with Wireshark shows a lot of packets missing. When following the RTP stream "sequence number", on about every tenth number there is a missing packet. And it is not a network problem, it does it even when streaming unicast between two computers on a straight piece of cable, or even when streaming from localhost to localhost. I get missing packets.Now I am quite confused, as if there is a problem with my computer, or if the current version of VLC is so uselessly buggy (I found other issues within minutes).Any ideas? Shall I report this as a bug? What other can be tested? (apart from trying a different computer to stream from)

author: Yansi
author_rank: Super Contributor
timestamp: August 18, 2019, 10:28:59 am
content: Well, not a bug in VLC, a feature of Windows instead.I have summarized the solution here:https://superuser.com/questions/1472275/rtp-streaming-using-vlc-getting-huge-transmit-udp-packet-loss-on-my-pc-why/1472521
What old 74xx and similar usually fail? - Page 1
Forum section: electronics / projects

author: ddavidebor
author_rank: Super Contributor
timestamp: June 29, 2013, 08:54:27 pm
content: Hi.In repair instrument i usually found various 74xx, flip flop, shift register ecc eccWhat of this old chips is likely failed more probably?

author: Unknown
author_rank: Unknown
timestamp: June 29, 2013, 09:08:09 pm
content: I think in general, the more complex the chip and more dense the die, the more likely it is to fail. HCMOS is more likely to fail than TTL, for example, because the FETs are more fragile.On the other hand, as a whole, the discrete components surrounding the chips are much, MUCH more likely to fail than the logic chips, which by all regards are usually rock solid.

author: free_electron
author_rank: Super Contributor
timestamp: June 29, 2013, 09:15:19 pm
content: Hcmos is not more prone to failure than anything else.There are a few notorious problematic parts. Like the old grey ic packaging. Those were catastrophic. They let moisture in leading to purple plague... This was solved after passivation became the norm.

author: Unknown
author_rank: Unknown
timestamp: June 29, 2013, 09:17:57 pm
content: I disagree, because HCMOS is more sensitive to external static. Given a well designed circuit, I generally agree, but given a poorly designed circuit, the same chip with the same static charge may fail more as an HCMOS than a TTL.I'm certainly willing to listen to counter arguments. I've been wrong before.

author: nctnico
author_rank: Super Contributor
timestamp: June 29, 2013, 09:29:20 pm
content: Quote from: ddavidebor on June 29, 2013, 08:54:27 pmIn my experience it can be any chip. I've seen simple AND gates fail. Measuring to find the problem is the only way. Poor logic levels (half way) or chips with nothing at their outputs are suspicious.

author: digsys
author_rank: Unknown
timestamp: June 30, 2013, 12:16:11 am
content: Except for a few known "bad" parts - in general, if they've lasted this long, they live forever. The bad? parts were things like 4013, 4017 etcThey always had noise / glitch issues. Usually the ones that fail are where they wire up directly to a connector, usually Inputs, and thatconnector starts to fail. Many designs never bothered with noise filtering at connectors.
What on earth happened: 8052 serial - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: November 19, 2015, 12:17:47 am
content: Hello all!I'm going to have to call on your minds again! Just got a 1988 8052 BASIC development board. quite nice, looks almost brand new. Had serial and some 8255s for I/O.Now, To do a quick "hello world" and see if it was any good (sold as is), I removed the 1488 and 1489 RS232 drivers, found the serial RX/TX and ground point, and hooked it up to an arduino via the 1488/89 sockets.After fiddling with the baud rate, It was fairly high: 115200bd - it worked great. Got the prompt and could write commands to it etc.Then after ca. 10 mins, it just turned to writing gibberish back at me. As if it was at a wrong baud rate.It still returns strings when you send characters, but only random characters.I tried to switch PSU's, tried with a laptop instead of std. pc. Could be a noise /skew thing, since it's really just long loose jumper leads to an arduino, but it just seems drastical to stop so sudden. Did the 8052 die/get damaged? Would it still function enough to send serial gibberish?`I hope someone has some experience with similar problems.Thanks in advance,Christoffer

author: free_electron
author_rank: Super Contributor
timestamp: November 19, 2015, 02:12:18 am
content: the 8052 ah basic autodetects baudrate at powerup.to do this , the FIRST character received after power up must be <SPACE>. so most likely what happened is that you cycled power , the 8052 went into autodetect and you sent something else than a space character. this throws off the baud detection routine.The autobaud detector works by measuring the time between edges of bits. they check the edge of the start bit and the first bit that is high in the space character ( space is ascii 32 so bits 7 6 5 are low , but 4 is the first one that is logic high. by measuring this time they figure out the baudrate.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: November 19, 2015, 11:48:20 am
content: Thank you! That's the info I was missing!Guess I should have read the 8052 BASIC datasheet..--Christoffer

author: free_electron
author_rank: Super Contributor
timestamp: November 19, 2015, 03:05:36 pm
content: you're welcome.i loved that cpu. if you type <CTRL>W <CTRL>C you will get the easter-eggi once had the rom loaded into an optimised 8052 (oregano systems) i instantiated in an FPGA.clock the thing at 150MHz on a 4 cycle machine and watch it fly !
what on earth is this thing for - Page 1
Forum section: electronics / projects

author: silly sausage
author_rank: Regular Contributor
timestamp: January 21, 2025, 08:01:07 am
content: can anyone explaine this thing on aliexpress? lol.https://www.aliexpress.com/item/1005005816897290.html?spm=a2g0o.detail.pcDetailBottomMoreOtherSeller.5.5ca0YalsYalsYH&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.14452.396806.0&scm_id=1007.14452.396806.0&scm-url=1007.14452.396806.0&pvid=151cdc56-9ed6-4ed2-bb11-a530fa7618ec&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.14452.396806.0,pvid:151cdc56-9ed6-4ed2-bb11-a530fa7618ec,tpp_buckets:668%232846%238108%231977&pdp_npi=4%40dis%21GBP%2158.74%2146.99%21%21%2170.03%2156.02%21%40211b61d017374461988778938e99f0%2112000034453203516%21rec%21UK%212308464272%21X&utparam-url=scene%3ApcDetailBottomMoreOtherSeller%7Cquery_from%3A&search_p4p_id=20250120235638916304621941989190631_0

author: shabaz
author_rank: Frequent Contributor
timestamp: January 21, 2025, 09:46:55 am
content: (Made the subject title more relevant)

author: ledtester
author_rank: Super Contributor
timestamp: January 21, 2025, 09:56:02 am
content: It's a "grounding box":https://en.xangsanecn.com/products_detail/c-_detailId%3D1189936184663347200.htmlThis page talks more about why you really need to get one for your hi-fi system:https://quartzacoustic.com/audio-ground-box-the-whys-and-the-hows/

author: moffy
author_rank: Super Contributor
timestamp: January 21, 2025, 10:18:44 am
content: Ah, an "Audio Electron Black Hole".P.S. What happens when it eats all of the "Audio Electrons" will everything become positive?

author: coppercone2
author_rank: Super Contributor
timestamp: January 21, 2025, 10:22:54 am
content: i wonder if you can get a connector on a black hole would it be a good ground, to put one near a planet and run a orbital litz tether to a black holeperhaps a neutron star is more practical for now because the connector is easier
What other 4 Channel Scopes are there? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: November 28, 2013, 03:56:32 pm
content: Hi Everyone,I've got a DS2072 which I love, but the one thing it doesn't have is 4 channels and I sometimes could really use 4 channels.I tried a DS1074Z, hoping it would be a nice compliment to my DS2072 for when I needed 4 channels, but it just isn't working out for me. I don't want to knock it for others who love their Z series, but for me it is such a departure from my DS2072 in terms of user interface and feel. The final straw for me was the counter. I don't see why they wasted screen real estate on the square wave signal icon before it, but moving the trigger threshold up or down on the signal will result in a stable waveform display as you would expect, but the counter going down significantly towards the top or bottom of the wave.So, back to the question at hand. I was thinking about upgrading to a DS4014, but I mostly use it in a sensitive noise environment and it sounds like the fan is bit a noisy and I don't really want to break it open to replace the fan, and it is a lot of $$$. I'd sell my DS2072 if I moved to a DS4014.So now my question is - are there any other 4 channel scopes I should consider? I love Rigol products, but I don't know of anything else that they have besides the DS4014 or DS1074Z. I sure wish they would come out with a DS2074!What else should I look at?Maybe I should just stick with 2 channels and get a LogicPort...

author: george graves
author_rank: Super Contributor
timestamp: November 28, 2013, 04:46:05 pm
content: If you don't need 4 channels all the time, why not get a older analog 4-ch scope to compliment your DSO? Just a thought.

author: AndersAnd
author_rank: Frequent Contributor
timestamp: November 28, 2013, 05:21:29 pm
content: Four 2000 class (2GSa/s Real-time Sampling Rate) alternatives available with both 2 and 4 channels and optional MSO:Siglent SDS2000 Serieshttp://www.siglent.com/en/product/detail.aspx?id=100000008529687&nodecode=119008001GW Instek GDS-2000A serieshttp://www.gwinstek.com/en/product/productdetail.aspx?pid=3&mid=7&id=1349Hameg HMO Compact Serieshttp://www.hameg.com/720.0.htmlAgilent InfiniiVision 2000 X-Serieshttp://www.home.agilent.com/en/pc-1940892/infiniivision-2000-x-series-oscilloscope

author: w2aew
author_rank: Super Contributor
timestamp: November 29, 2013, 05:09:24 pm
content: I'm kind of partial to the Tektronix MSO2000 and 3000 series...http://www.tek.com/oscilloscope#cat_mixed_signal
What pad size is needed for this BGA chip? - Page 1
Forum section: electronics / projects

author: jacksexton
author_rank: Newbie
timestamp: July 16, 2016, 06:41:31 pm
content: I'm trying to figure out the pad size to use for my footprint according to this datasheet. The last page in the datasheet has the package dimensions.http://linux-sunxi.org/images/4/4b/Allwinner_H3_Datasheet_V1.2.pdf. I've also posted the relevant information in a picture below.The bottom right has the dimension for the pad size but I cant figure out the actual measurement from the table it provides. I'm confused by the labeling, do I use eee or fff? and what is the purpose of C A B symbols next to eee and C next to fff.

author: kony
author_rank: Regular Contributor
timestamp: July 17, 2016, 10:01:25 am
content: Package ball diameter is valueb, values eee and fff are positional tollerances of pad location (as said by the first symbol of cicle with cross). Both says nothing about how exactly shall PCB pad look alike.Symbols C, A and B are references for the given tollerance field (circular, as makred by the symbol of diameter before numerical value (variable)).Get technology specifications from your PCB fabhouse and work out from there if SMD or NSMD pads, and how big they can be - so you can fit vias where needed without violating design rules.EDIT:Fotgot to add - M in circle means "maximum material condition" - which translates that given tollerances of pad location and size shall be achieved with maximum of material preserved in there. I can only assume that in case of BGA it means "maximum amount of solder applieable".

author: jacksexton
author_rank: Newbie
timestamp: July 17, 2016, 02:22:26 pm
content: thank you for that, the diagram was confusing.
What part number is this IR photodiode (square, side looking) - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: September 08, 2021, 09:36:46 am
content: I'd like to source an IR photodiode similar to the image, because it seems to work nicely.The unit shown is used in a commercial smoke detector. So far I have found a PD638B as somewhat similar looking. Not sure if the metal shield in the photo is part of the diode or added on.

author: mjs
author_rank: Regular Contributor
timestamp: September 08, 2021, 11:37:14 am
content: I better picture would be helpful.

author: 741
author_rank: Frequent Contributor
timestamp: September 09, 2021, 07:18:48 am
content: Apologies for the photo quality - these were sent to me by someone else.Still not very clear, but it actually seems more rectangular than square, and there appears to be a curvature on the face.

author: mjs
author_rank: Regular Contributor
timestamp: September 09, 2021, 11:13:56 am
content: Shield is probably added on later - I've seen only some remote control receivers with metal shield.Check out QSE773, BPW83, BPW41N.It might also be a phototransistor, but those typically have a lens and rather small chip.
What parts do i need for a cable finder ? - Page 1
Forum section: electronics / projects

author: JanJansen
author_rank: Frequent Contributor
timestamp: August 18, 2017, 01:49:34 pm
content: Hi, i wanto drill some holes in the wall, Bosch has this nice thing for finding cables :https://www.powertoolshop.nl/product/217135/bosch-pmd-10.html?ref=370682&label=22715-AGI-42486036956-ASI-338901960870-217135&gclid=EAIaIQobChMIrNaW4fTg1QIVEBMbCh193QY0EAQYASABEgI_fPD_BwEIn no 80 years i,m gonna spend 80 euro for finding a cable, so maybe you has some clues about how to build this very easy ?thanks in advanceoh : any teardowns on this one ?thanks

author: DmitryL
author_rank: Regular Contributor
timestamp: August 18, 2017, 02:33:14 pm
content: Everything depends on what you want: find a cable or have a fun building your own cable finder.I have built my own. I uses a very small transformer from old radio (approx 1.5x1.5x1cm) as a sensor (pick up coil). It picks up magnetic filed from the current flowing throug the cable.I have disassembled the transfomer and removed some I-type plates to have an open core from one side. it looks like: "I_I_I" with the original winding on a bobbing on the central pole.It is connected to the amplifier with K~=400 (a couple of op.amps), everything is powered from a couple of AAA batteries. Then headphones socket.How to operate:The best result is achieved when an evergy-saving bulb is connected to the socket nearby - they inject a LOT of harmonics into the mains. So, just move a pick-up coil and listen either for 50Hz hum or buzz from noisy load.This allows me to locate mains cable with about 1cm precision inside the wall about 1-5 cm deep.The cost was nearly zero. And of cause, it doesn't detect cable without AC current

author: cdev
author_rank: Super Contributor
timestamp: August 18, 2017, 02:34:47 pm
content: Buy one online for only a few bucks. They generate a warbling audio square wave. The probe is some wire wrapped around a ferrite rod, so use that with an audio amp. Or use a tape player playback head.A playback head lets you use it with PCBs Very useful.
What performance factors matter for an electronic load? - Page 1
Forum section: electronics / projects

author: jbb
author_rank: Super Contributor
timestamp: May 23, 2018, 06:32:06 am
content: So I am thinking about developing a high performance electronic load, but I am not sure what performance factors really matter.My experience with purchase electronic loads (admittedly they weren't high quality ones) includes a few pitfalls:Often they are oversized (well, that's our fault for buying an oversized one :-))Their minimum operating voltage (a.k.a. compliance voltage) can be higher than I'd likeTheir ramp up from 0 mA to some mA can have big ugly transientsLimited dynamic range. A lot of modern electronics can have uA sleep currents and >1A peak currents to run radios etc.If the input voltage is zero and the load is therefore lower than the setting, the internal control loops wind up. When the input voltage comes back, the electronic load then sucks down a huge inrush of powerTendency to oscillate and/or limited bandwidthTendency to have current spikes and dips when input voltage changes suddenly[\li]In addition to this, a lot of hobbyist designs seem to have pitfalls:No reverse polarity protectionNo overload protectionChoice of parts which have widely varying offsets etc.Inability to go down to zero current in all conditions (e.g. depends on your luck with opamp offset voltage)I want to focus on making a really good core current sink by addressing these problems (and not spending huge piles of money either). But these may not be the only problems - what have I missed?------I'm thinking about a small load to reflect what I would like: say 0-2A, 0-15V, 10W maximum. As an extra credit undertaking, I'm also thinking about ways to get a dual range in there, e.g. 0-20mA and 0-2A, with seamless switchover.

author: larsdenmark
author_rank: Regular Contributor
timestamp: May 23, 2018, 08:40:29 am
content: If you haven't already watched Scullcom's electronic load project now is the right time:The series is long, but covers most of the things one would consider relevant.More things to consider on top of your list:Constant current, constant resistance and constant power should be supportedShould external control be supported for setting the parameters?For testing batteries a logging feature is necessary. People seems to want this on an SD-card.What happens if you connect 100 V to the unit when it is not powered?How large/fast changes do you expect the source will vary? How fast must your load respond to that?What accuracy do you need?

author: nctnico
author_rank: Super Contributor
timestamp: May 23, 2018, 04:10:12 pm
content: Sounds more like a source measuring unit with current sinking abilities.
What plug to use? - Page 1
Forum section: electronics / projects

author: mkiijam
author_rank: Regular Contributor
timestamp: May 30, 2025, 05:01:14 am
content: I'm trying to change over a plug on an amp that I want to make sure no one ever accidentally puts it into 240I want 120VAC at 30 amp

author: pqass
author_rank: Super Contributor
timestamp: May 30, 2025, 05:28:18 am
content: NEMA 5-30P, or14-30P (dryer) or 14-50P (stove) but only use neutral and one line (leave other line unconnected).Seeherefor the NEMA chart.
What power supply to use for project? - Page 1
Forum section: electronics / projects

author: Finndersen
author_rank: Newbie
timestamp: February 23, 2015, 01:41:27 am
content: Hello,I'm planning a project which will include the following components:Circle of LEDs - there are 6 in series at about 3v each so requires 18v to turn them all on.. could possibly re-wire it to have two sets of 3 in parallel at 9v? - apparently 150mAhttp://www.ebay.com.au/itm/50-60LM-3W-10LEDs-5730-SMD-White-32mm-Circle-Aluminum-Base-PCB-Plate-4pcs-/301427050916?pt=LH_DefaultDomain_15&hash=item462e73c9a4Three more single LEDs at around 3v each12V DC motor which will draw about 350mA maxMini brushless motor driven by 6A ESC, ESC is designed to be powered by 2S Li-po battery which is 7.2V? Not sure what acceptable voltage input range of ESC is.http://www.ebay.com.au/itm/Brushless-Outrunner-Motor-4000-3500-KV-6A-ESC-High-Quality-New-/151415070145?pt=AU_Toys_Hobbies_Educational_Toys&var=&hash=item23410a9dc1http://www.ebay.com.au/itm/Emax-6A-Speed-Controller-ESC-SimonK-Firmware-Multirotor-6amp-/301341054118?pt=LH_DefaultDomain_0&hash=item46295394a6Arduino - could be powered off 5V output from above ESCSo I've got some high voltage requirements (12V motor and LED circle) and high current requirements (brushless motor). I will probably never need to run the brushless motor close to max speed so maybe only 2A or so required for that? Otherwise if absolutely necessary I could try find another motor solution.I was looking at power supplies along the lines of something like this.http://www.ebay.com.au/itm/DC12V-24V-60W-400W-Universal-LED-Light-Strip-Regulated-Switching-Power-Supply-AU-/171357393625?pt=LH_DefaultDomain_15&var=&hash=item27e5b252d9Would this be appropriate in combination with some regulators? I'd prefer something smaller and lighter though..Thanks for any help!
What programmer can work with TC58DVM92A5TA10 - Page 1
Forum section: electronics / projects

author: stojke
author_rank: Regular Contributor
timestamp: January 22, 2018, 04:12:49 pm
content: Hi. I have two devices that use an TC58DVM92A5TA10 E2PROM memory. One of them is having memory corruption problems in the said chip and the other works perfectly well. I want to read the good one and write it into , or replace , the problematic one.My current Kung-Fu programmer, the RT809F with PEB-1, claims it is capable of working with various NAND memory VIA of AUTO NAND algorithm and even mentions AUTO NAND function in its RT809F manual.It does not have AUTO NAND function in its software.Can any one suggest a good quality programmer that is able to work with Toshiba TC58DVM92A5TA10 and is easy to maintain (Sockets) while able to last a couple of years? (Ive seen some good into on an so called TNM 5000 , but unsure will it work with the chip im having problems with)

author: amyk
author_rank: Super Contributor
timestamp: January 23, 2018, 02:50:19 am
content: Are you sure you don't mean TC58DVM92A5TAI0? Because according tothe datasheetthat's a pretty standard small-block NAND which I'd guess basically any programmer would be able to work with.

author: stojke
author_rank: Regular Contributor
timestamp: January 23, 2018, 09:30:48 am
content: Should work, but does not.RT809F has no ability to detect or be configured to use that NAND chip (At least I guess, it is all in Chinese). When selecting an similar one, Samsung K9F1208U0 it does nothing, reads only 00, and AUTO NAND is only selectable in the RT809H software set (Which is RT809F with PEB-1) and said software wont work with an RT809F.What is getting on my nerves is that in the RT809F manual they mention AUTO NAND algorithm and there is none of that, and to make it even worse RT809H comes with a lot of algorithm files that are not usable by RT809F software (As it is software locked).
What PSU for "1000 W ZVS induction heater" - Page 1
Forum section: electronics / projects

author: Martinn
author_rank: Frequent Contributor
timestamp: March 19, 2023, 12:59:52 pm
content: Hi all,I got hold of one of these chinese "1000 W induction heater" moduleshttps://www.aliexpress.com/item/1005004988301529.html.Currently I don't have a power supply for it and I am not sure what to buy. As specs are Chinese I would expect it not really does 1 kW or 48 V - maybe for a second or two and then transform itself in a cloud of smoke.Ali has supply modulehttps://www.aliexpress.com/item/1005002205612231.html- but 3 kW is a bit excessive. I checked ebay.de for server power supplies, but found only 12 V ones.Then there's also lab supplies like thishttps://www.aliexpress.com/item/32784933287.html32 V 32 A one. I don't really need a that beefy lab supply so I don't want to spend much more on an "official" high quality one.What it comes down to is: What are resonable figures (voltage, power) this module can be powered with without exploding within a few seconds? 36 V 500 W? What are your experiences?

author: wasedadoc
author_rank: Super Contributor
timestamp: March 19, 2023, 01:07:15 pm
content: You need to edit the first hyperlink and remove the trailing period.

author: Martinn
author_rank: Frequent Contributor
timestamp: March 19, 2023, 01:11:01 pm
content: fixed - thanks!
What RF connector is this? - Page 1
Forum section: electronics / projects

author: mojoe
author_rank: Frequent Contributor
timestamp: March 01, 2024, 10:05:07 pm
content: From the pictures, I thought it was an MCX, but when I got the boards, I find out it's something else.

author: David Hess
author_rank: Super Contributor
timestamp: March 01, 2024, 10:30:35 pm
content: That looks like SMB.

author: mojoe
author_rank: Frequent Contributor
timestamp: March 02, 2024, 12:34:35 am
content: Thanks. I thought it might be SMB, but wasn't sure, never having used SMB. I ordered some SMA adapters.

author: David Hess
author_rank: Super Contributor
timestamp: March 02, 2024, 01:30:18 am
content: SMB is useful where connections may be temporary, like test equipment, and to avoid connecting incompatible signals.
What should be the gain of buffered phase shift oscillator? - Page 1
Forum section: electronics / projects

author: hkBattousai
author_rank: Regular Contributor
timestamp: August 04, 2014, 06:24:09 am
content: I understand that gain of phase shift oscillator must be at least 27, and shouldn't be very high to preserve output sinusoidal waveform. I don't know how this magic number is derived, but it said so everywhere.(1.5M) / (55.2k) = 27.17What should be the gain when the oscillator is buffered at every stage?(1.5M) / (180k) = 8.33I readan online document (pg 278)about it. It doesn't mention this detail, but sets the gain as 8.33.What should be the gain for the buffered case? What is the rule for setting it?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 04, 2014, 07:10:12 am
content: Minimum gain should be around 8, because the phase shift is 60 degrees each, and an attenuation of 0.5 each. 1 / (0.5)^3 = 8. This is very easy to illustrate with phasors. You want it a little bit more than that, of course.Also works nearly as well if the chain of RC-RC-RC is made with increasing resistances and decreasing capcaitances, so the R*C product of each pair is the same, but the resistance goes up by, say, 10x each stage. So you have 10k + 0.1u, 100k + 10n, 1M + 1n. The actual gain of this network will be slightly less than 1/8th (and thus the amplifier must have somewhat more than 8 gain), because of the loading effects of each RC on the previous pair, but not as bad as in the equal-value case that needs 27x gain.Tim

author: LvW
author_rank: Frequent Contributor
timestamp: August 04, 2014, 10:59:15 am
content: Why do you intend to use three opamps for such a simple oscillator? This circuit makes sense only in case you need several signla at the same time which are phase shifted against each other.More than that, as shown in your circuit diagram, you are forced to use very large resistors for the inverter because of loading errors.Why not using a topology with only TWO uncoupled equal RC sections working directly upon an inverting integrator stage (classical inverting integrator)?The integrator provides +90 deg and both RC sections cause a phase shift of -90 deg at the desired frequency.Hence, the oscillation condition (unity loop gain for one single frequency) can be fulfilled.Here are the formulas:* Three equal resistors R, two equal capacitors C; Integrator capacitor Co=C/12* Oscillation frequency wo=SQRT(3)/RC.
What should the input for a subwoofer look like ? - Page 1
Forum section: electronics / projects

author: MathWizard
author_rank: Super Contributor
timestamp: March 08, 2021, 10:36:38 pm
content: I'm repairing/rebuilding a stereo, whose SMD PCB I messed up, and it's full of shorts now. So I'm re-making the pre-amp/op-amp section, with through-hole parts.The new op-amps, of the right type, didn't really work at DC, let alone AC, and I swear I damaged 1 already on this new circuit, and there's no external path to gnd.So I tried some other's like a jrc4565, and they seem just fine for a rear speaker once I stopped some oscillation. Sine wave in, sine wave out.But for the subwoofer section, I'm getting more U shapes, than a sinewave, especially at 50Hz-1kHz, but it never goes way. The voltage swing is well within the rails, this is just a pre-amp, so there's not much gain, just filtering, and this is unloaded testing, )Adding some capacitance to the I/P network, I can get sinewave in, pretty close to sine wave out again.But I've never seen what a subwoofer does, should I be trying to get a sinewave in. perfect sinewave out ?

author: Manul
author_rank: Super Contributor
timestamp: March 09, 2021, 12:39:16 am
content: I never looked subwoofer signals, nor I'm an audio guy, but I would expect nothing less then a perfect sine. I mean, why it should not be a sine at preamp stage? At power stage it is likely a class D stage, so some sort of PWM with filters which might be better or worse, but the input to that should be a clean sine. Distortions at low frequencies would be very annoying for the ears.
What should the vacuum pressure of a desoldering gun be  - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 04, 2020, 12:43:44 am
content: They really do call it a vacuum pressure. My old Hakko 707 is spec'd at 600mmHg of vacuum pressure, which means 23 inches of mercury below atmospheric of 30 inches, I guess. The newest Hakkos are rated the same. My 707 has a pump with a home-made diaphragm in there since the original part disintegrated.http://www.hakko.com/english/products/hakko_fm204_set.html#productNavThe 707 does work, but since I finally received my eBay vacuum gauge, I jammed the tip of the iron right into the port hole of the thing and pulled the trigger. I measure about 18 inches.Is the vacuum pressure rated right at the the pump or at the tip of the iron? And how much vacuum am I possibly losing in the tubing and the joints in general?It's nothing major, just curious.

author: Circlotron
author_rank: Super Contributor
timestamp: August 04, 2020, 01:00:14 am
content: If the flow has stopped and there are no leaks there will be no loss of vacuum regardless of any restrictions.
What size transformer do I need? - Page 1
Forum section: electronics / projects

author: iXod
author_rank: Frequent Contributor
timestamp: December 05, 2019, 05:15:08 pm
content: A 36vdc gear motor is PWM’d (using a MOSFET) to achieve variable speeds. The unregulated supply is full-wave rectified and filtered with a single 1000uF electrolytic cap.The original transformer secondary went open-circuit and a replacement is NLA.What secondary voltage should I use to achieve the 36vdc needed to drive the motor?Thanks.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2019, 05:23:37 pm
content: Around 28VAC, though you probably, unless that is a really tiny motor, will want a little more capacitance on the transformer. Current rating will also have to be around 1.5 times the full load current of the motor, unless you have some operating time limits that have the motor running at low power most of the time, and rare full power operation, though I suspect your transformer was undersized for that reason, so it was cooked nicely.

author: iXod
author_rank: Frequent Contributor
timestamp: December 05, 2019, 05:52:28 pm
content: Motor label says 36 vdc, 30 watts. No HP or amps rating.So 6.25A at 28 volts should be good? ::https://www.mouser.com/ProductDetail/Bel-Signal-Transformer/A41-175-28L?qs=sGAEpiMZZMvwUzoUXIIvyZ8riR3Pta28dcX6E4y%2F7GMRhEVEAcvW3w%3D%3DThanks.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2019, 08:01:13 pm
content: Should work well enough, and large enough that it will survive stalled operation for a while, at least longer than a fuse takes to blow. Bit overkill, you could get by with a 3A transformer and still work, but so long as the bigger one still fits in the same volume it will work. The A41-80-28L will also work with your motor load, as it draws only 1A roughly, with probably a 3A start up current, which the transformer will survive easily with little problems.