hybridfree/eevblog-posts huggingface dataset:
Some questions about a PCB - Page 1
Forum section: electronics / beginners

author: dog80
author_rank: Regular Contributor
timestamp: January 08, 2013, 09:43:31 pm
content: I recently swapped my old Rokonet RP-808 alarm panel with a newer one because the old one didn't support ContactID.Anyway, I was examining the old alarm panel PCB and have some questions.Here is a pic of the back side at the bottom, where the zones connect1) The big copper traces are the ground plane. Why does it have this checkered pattern?2) Why the wiggly trace between positive and negative in the red circle?3) What's that in the blue circle? I measured it with a MM and looks like a resistor?4) What is the device in the yellow circle? I tested it and it looks like a diode, but it has 1K resistance when forward biased.Also what is this mystery device? I couldn't find a datasheet.The engraved circle at the center says "MEXICO AA"

author: SeanB
author_rank: Super Contributor
timestamp: January 08, 2013, 10:00:22 pm
content: Checkered pattern was common as there were worries with older soldermask about wrinkling with large copper areas, so the checkerboard pattern is common. The red circle adds a small amount of inductance, probably designed in to make a fusible track that will arc over to the ground if there are large surges like lightning. Blue is a spark gap to dissipate lightning voltages to the grounded chassis.Yellow circle is a diode in a MELF package, here used as a catch diode across the output.The transistor is a TIP110 darlington, nothing exotic.

author: AndyC_772
author_rank: Super Contributor
timestamp: January 08, 2013, 10:21:30 pm
content: Quote from: dog80 on January 08, 2013, 09:43:31 pmAt a guess, it's to reduce the percentage coverage of copper on the PCB so that the PCB plating becomes more even. It's helpful when fabricating a PCB to make the coverage as uniform as possible, otherwise the copper builds up in some areas more than others during the plating process.QuoteI've seen things like this on alarm boards before, and I'd argue that they serve no practical purpose whatsoever. Wiggles like that might have a practical effect at frequencies of 100's of MHz or above, but otherwise they achieve nothing. A bit of an alarm industry urban legend, perhaps?QuoteThere's no actual component there, so at a guess maybe it's a deliberate attempt to create a small creepage distance between the pin and ground. Such a small gap might act as a spark gap in the event of a high voltage transient on one of the alarm wires, though I don't see any supplementary protection.QuoteIt's a diode, the resistance you measure will depend on the meter's test current.QuoteTIP110, general purpose darlington NPN transistor:http://www.onsemi.com/pub_link/Collateral/TIP110-D.PDF
some questions about a phaser fx circuit - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: June 30, 2022, 03:40:42 am
content: [ Attachment Invalid Or Does Not Exist ]this is the phaser circuit from a musicman HD150 guitar amp.it's slightly unique in that the amp had a push-pull pot on the speed setting that you could pull for a manual phaser, it stops the oscillator and the output of the oscillator will be at +16V, so the depth control then controls the phaser manuallybut why the 25k pot+ 9.1k resistor going to that connection? since it connects within the feedback loop of the phase shifting circuit.the control is labeled "phaser"...
Some questions about Agilent handheld oscilloscope - Page 1
Forum section: electronics / beginners

author: kamcm
author_rank: Regular Contributor
timestamp: March 17, 2014, 12:27:29 am
content: Some question about Agilent handheld oscilloscopeQuestion 1My Agilent 1602B showing up extra horizontal red lines when using autoscale, Is this normal ? Please advice!http://youtu.be/ufOb8QbUkaMQuestion2My Agilent U1602B having BurnMark, is there anyway to mitigate the problem?More obvious in the startup screenQuestion3I received that U1602B from Agilent a few days ago.Is there anyway to confirmed whether it's a brand new replacement or refurbished replacement?Please help,Thanks

author: Rigby
author_rank: Super Contributor
timestamp: March 17, 2014, 12:33:21 am
content: LCDs don't get burn-in, they get bias, which goes away with time. My experience with LCD bias, it takes hundreds of hours to get bias, and just a few hours to get rid of it.I don't know about the red line. Looked like you had CH2 on or something and it showed a flat line at 0. And, it didn't look red, so I'm not sure I'm looking at the right thing.

author: kamcm
author_rank: Regular Contributor
timestamp: March 17, 2014, 12:57:39 am
content: Quote from: Rigby on March 17, 2014, 12:33:21 amThanksI tried to mitigate the problem by keep it on with meter interface for more than 4 hours.However, the LCD bias / burn-mark of scope interface still there.Btw, I realized the red line is related to trigger mode, but I am not sure if that horizontal lines are "designed to be visible"http://youtu.be/ufOb8QbUkaM
Some RFID questions (or possibly NFC) - Page 1
Forum section: electronics / beginners

author: XOIIO
author_rank: Super Contributor
timestamp: March 15, 2016, 09:02:40 pm
content: Figured this was a bit better suited to this forum, I'm thinking of getting a cheap usb RFID reader/writer off of ebay as well as some of the business card style RFID cards.I am not sure how they go about programming with these, or if you can even program them the way I am thinking, but I am wondering if you can actually write some text data to RFID cards/tags, I don't know how many characters you could get it, it is only 264 bits available in some of the ones I found, but being able to fit a few bits of info, or even a few sentences, would be pretty cool, if it would just spit it out as plain text when hooked up to similar readers. (could even encode it somehow as well)Anyways, I figure there should be some people here who have messed around with this, and maybe even done the same thing, and might be able to point me towards the type of reader/writer I would need, and give a bit of insight as to how you program them on a PC. (can't see any software mentioned, and hell, half the cards that say "writer" in the title then say it's a reader only)I had thought about doing the same with magstripe cards since those are cheap, but the writers are ridiculously expensive, and when you compare them to RFID they are insane. Tried to find why they haven't come down and all I found was a post I made ages ago in general chat with no replies.edit: seems like I would need to go for 13.56 mhz cards to be able to write to them, and this seems like it might be a decent little kit to start playing with them.http://www.ebay.ca/itm/New-13-56MHz-Separated-USB-Contactless-Smart-IC-Card-Reader-Writer-RFID-/400903763813?hash=item5d57b9f765:g:CsAAAOSwFnFV~2Gnedit 2: it seems NFC would be a good possibility as well, the cards are much, much cheaper, the readers are less common, but they can also be read/written to using android devices (don't have one right now so I would need a usb writer) but it seems they might not be able to store as much data.

author: Divvi
author_rank: Contributor
timestamp: March 15, 2016, 09:29:49 pm
content: You can use this to read/write to RFID cards or tags:http://www.ebay.com/itm/Mifare-RC522-Card-Read-Antenna-RF-Module-RFID-Reader-IC-Card-Proximity-Module-/311563538690?hash=item488aa25102There is an arduino library which should get you started:http://playground.arduino.cc/Learning/MFRC522
someone LIPOs expert there??? - Page 1
Forum section: electronics / beginners

author: dramoto
author_rank: Contributor
timestamp: July 22, 2016, 04:21:01 pm
content: Hi...Just trying to look at the doors of the knowledge of batteries. I began to use "logview studio" to check what is happend during the charge of my RC lipo´s. And I notice that the voltage current make a strange change in the curve from 4.05V to 4.1V cell voltage, during the constant current charging fase. Looking the curve it´s like inside the cell they are two batteries in serie (like two different chemistry), and from 3.70V to 4.10v is charging the first one, and at 4.10 begin the another one.Someone can explain for a dummy what is the reason for this? if they are one...It´s normal on all Lipo´s or maybe only in the brand that I have?ThanksFrom the attached graph, it´s the charge of a 3S Lipo. The upper blue line is the total battery voltage. Red line is the current. Next green line is the capacity.And at the bottom, three lines together of the voltage of each individual cell. Interesting too the peak in the voltage at 3.85V. Like it´s a point with more activity. I see interesting beacouse 3.85 it´s the recomended value for "storage" a LIPO.

author: Kilrah
author_rank: Unknown
timestamp: July 22, 2016, 04:45:12 pm
content: Not sure what you mean. The last graph clearly shows your 3 cells are well matched.

author: dramoto
author_rank: Contributor
timestamp: July 22, 2016, 05:07:25 pm
content: Sorry for my poor capacity of explain me in English.The information of the curve is great.I´m speaking about the "non-lineality" of the cell voltaje between the chart points 16:45 to 16:55. The "hump" that the cell voltage does from 4.05V to 4.10V.I suppose that it has a chemistry reason. I didn´t see until now jump´s or hump´s in the charging curves of NIMH or NICDAbout the little peak that is in the blue line at the chart point 16:20. I find it curious that it coincide with the recommended "voltage storage".

author: Kilrah
author_rank: Unknown
timestamp: July 22, 2016, 07:07:11 pm
content: Could be temperature, could be the quality of the contact in the charging wires, could be chemistry...The jump at 16:20 is very typical of a change in contact resistance in the charging cable, e.g. by just moving the battery or cables/plugs given that the cell voltage doesn't have the same jump.
Someone nice enough to check my board design? - Page 1
Forum section: electronics / beginners

author: Jac0bas
author_rank: Newbie
timestamp: August 26, 2017, 06:52:02 pm
content: Hi, I'm very new to electronics design and currently trying to finish up my first real thingy. I've got a working prototype and a board made in Eagle. Could someone more experienced please take a look at my board and tell me where I've screwed up?I want to get the board made by a chinese PCB house. Is this design ready for manufacture or am I missing something?Thank you in advance.

author: Jac0bas
author_rank: Newbie
timestamp: August 26, 2017, 07:12:34 pm
content: PDF looks pretty bad IMO, but there you go

author: daddylonglegs
author_rank: Contributor
timestamp: August 30, 2017, 09:45:29 am
content: Jac0bas,You could post:A pdf of the schematic.A pdf of the board, with one layer per page (this is probably what cleaningOut intended) or...The zip file you will send to your board house - including the gerbers.The raw schematic and board files can be helpful.The gerbers are probably the best files for checking, things can go wrong between the board file and the gerbers.You can check your footprints by printing the board layout on a 1:1 scale and physically placing your components on the printout. We don't have your BOM and, frankly, I'm not going to check each and every footprint on some random internet project. My regrets.Looking at your board two things stick out:The module you're using has an antenna drawn on it. This almost certainly requires the space around it to be free of conductors and so I think your copper fills (and possibly your connector labelled SERIAL and your LCD module) will interfere with the antenna. Check the datasheet for the module.You almost bisect your ground fill with tracks running along the bottom layer. The clock and data lines for your LCD running across this gap could give you EMI and signal integrity problems.

author: stmdude
author_rank: Frequent Contributor
timestamp: August 30, 2017, 11:07:03 am
content: After a (very) cursory look, it's not bad for your first attempt. We will be able to give you more detailed comments if you post the information the other people requested.The one thing that sticks out to me is the mounting-holes. There's not a lot of material left around the hole, so the corners might break off quite easily (or, even before you get the boards). I'd move them in a little bit if your case allows for it.
something strange?? or just needs a little explination - Page 1
Forum section: electronics / beginners

author: dmkmedia
author_rank: Contributor
timestamp: January 24, 2017, 05:50:49 pm
content: https://goo.gl/photos/WvLmUkrv45Jz3nyw6above is a video of something i was playing with a led matrix and one of the led's didnt work when testing so i went to de-solder it and put in a new oneand to my shock i found that when my soldering iron touched the LED leg the led lit up.as the soldering iron was not connected to the led's in any way apart the power supply for the led's and the soldering iron was pluged in to my home mains.how did it happen

author: mmagin
author_rank: Frequent Contributor
timestamp: January 24, 2017, 05:56:52 pm
content: Is your iron tip connected to the ground pin of the power plug?Is either the positive or negative of the power supply output connected to its ground pin?Are your outlets actually grounded? If not, the shared ground conductor (and as a result the iron tip, perhaps) can get quite a bit of AC voltage on it through Y capacitors.Just some things to think about. When my 'ground' was ungrounded, I was able to light an led between my fingers and 'ground'

author: dmkmedia
author_rank: Contributor
timestamp: January 24, 2017, 07:56:41 pm
content: i am in the uk and everything i plug in has a ground wire on the plug. everything is sharing a single power stack to protect against power surges. could this cause it some how?

author: mmagin
author_rank: Frequent Contributor
timestamp: January 24, 2017, 08:12:56 pm
content: I would certainly start by unplugging the soldering iron and the power supply and use a DMM to verify what, if anything, is earthed.

author: sleemanj
author_rank: Super Contributor
timestamp: January 24, 2017, 08:57:28 pm
content: It is pretty common. A modern led will emit visible light with *incredibly* little current, normal earth leakage and capacitive coupling more than sufficient. It's not uncommon in fact to have led light bulbs that glow when the switch is off, indeed many designs include measures to prevent it (because people prefer that a light switched off, is off :-)Personally, I wouldn't worry about it too much.
Sonoff POW ground questions - Page 1
Forum section: electronics / beginners

author: aandras
author_rank: Newbie
timestamp: September 10, 2021, 12:28:14 pm
content: Hi,i have problems understanding certain issues with my Sonoff POW. I have one that has a fault in the power supply part.It is not working with mains connected but working with usb serial connection and also if i feed directly 9V DC at the output of D3.Working means wifi connection and relay switching functions.I tried to measeure it and i find it strange that its ground (with the triangular shape) is connected to mains phase. I checked its schematic (https://wiki.iteadstudio.com/File:Sonoff_POW_Schematic.pdf)and it seems that that is by design like this (via R10 - 0.001 ohm and R25 - zero ohm). Is that common for devices with switching PSU-s? Can anyone help me to understand this?thank you,András

author: viperidae
author_rank: Frequent Contributor
timestamp: September 11, 2021, 07:16:24 am
content: Yes it is designed with mains reference and yes it is commonIt's much cheaper and easier to measure voltage and current with resistors.
Sony backlight inverter , transformer help - Page 1
Forum section: electronics / beginners

author: Seaofdep
author_rank: Regular Contributor
timestamp: September 26, 2017, 06:42:35 am
content: I have a Sony tv that would power on to the Sony logo then picture would disappear. I opened up the tv and powered it on ( safety first ) first thought was the backlight inverter. And tested voltage with dmm . And found indeed it was one of the transformers on the inverter. This is where I need help, can I repair the transformer and if not does anyone know where I can order one from? Any information helpsThank youPicture bellow , side marked with black is the faultSent from my iPhone using Tapatalk

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 04, 2017, 12:11:53 pm
content: I don't seem to be getting any help with my post anymore, am I posting on wrong page or am I missing something, please let me know if I am doing something wrong ..... update : I wasn't sure how to go about fixing inverter and didn't want to just buy one and swap it out when I see this as a learning experience. So what I ended up doing is completely removing ccfls and adding a led strip, I tested using external power supply and it is working very well. I would Like to wire led strip directly to tv power supply to avoid having two switches one for tv and other for led . I'm not sure if this is possible ?Sent from my iPhone using Tapatalk

author: Zero999
author_rank: Super Contributor
timestamp: October 04, 2017, 12:50:23 pm
content: That work but you'll probably find the LED strip doesn't give as good colour rendering at the CCFLs.Is there a relay which turns on, when the TV is powered up? Perhaps you could use that to power the LED strip power supply.

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 04, 2017, 01:00:29 pm
content: Oh, I didn't really check for color rendering, just a basic scan of channels, hmm well that's fine I going to use it as a monitor for my security system.Yeah there is a relay that turns on but there really isn't any room to add the led strip power supply unless mounted on the outside someway ,Thanks a lot for your response. I'm still learning and taking it a step at a time and any help is greatly appreciatedSent from my iPhone using Tapatalk
Sony CXA1145 only outputting black and white composite? - Page 1
Forum section: electronics / beginners

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: February 07, 2015, 10:49:59 am
content: So, I've been modifying a Sega Master System II today.Adding a composite and audio rca sockets, as well as an svideo socket, and 9 pin RGB socket.RGB looked good...svideo was decent, buy a little more blurry...composite was kinda over exposed, too much brightness or something.... and then, it turned black and white...Did I break the 1145 IC?I may have at one point had all three outputs connected to the one TV, but as they're separate outputs, I assume nothing could have been overloaded?Original:Modified: (edit: the sync pin is actually connected via the same 75r/220u circuit as everything else, its not directly connected like the diagram shows)All unlabelled resistors are 75ohm, capacitors are 220u.The 1145 is technically meant to have an amplifier on one of the svideo outputs... is it possible I broke that by overloading the chip?Any help would be excellent! (going to go test svideo and rgb again)

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: February 07, 2015, 11:05:28 am
content: I can confirm, svideo and rgb are still in colour.I'd tested the composite video mod before I did anything else, and it worked fine, but now I've done the other mods...

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: February 07, 2015, 11:49:52 am
content: Ok, its all sorted, I had tied something to ground on the motherboard that shouldn't have been.. my bad!
sony hd projector - Page 1
Forum section: electronics / beginners

author: kevin1
author_rank: Newbie
timestamp: July 27, 2014, 05:19:48 pm
content: HiI have a problem with my sony hd projector, there seems to be a green pixilated blob forming at the side of the image. Ive done some research and think it could be the lcd unit beginning to fail the blob started about 5 pixels wide but it is gradually getting bigger. Any info on cause and how to get it repaired would be appreciated.

author: German_EE
author_rank: Super Contributor
timestamp: July 27, 2014, 05:28:29 pm
content: Sorry to be the bearer of bad news but yes, you have an LCD failure. The straight line at the top of your blob is a crack in the LCD.

author: kevin1
author_rank: Newbie
timestamp: July 27, 2014, 05:40:25 pm
content: Thanks for your reply, do you have an idea what it would cost to repair this?
Sony IC RS-70-TU part replacement? Drop-in component? - Page 1
Forum section: electronics / beginners

author: Sirgeorge
author_rank: Contributor
timestamp: September 24, 2020, 05:43:56 am
content: Hey, just curious if there is a drop in replacement for this. I'm not entirely sure if this is a bog standard IR sensor or if there is some specific factor I need to take into consideration for it. Any specsheets for it? Anything specific I should keep in mind when looking for a drop-in replacement?

author: Sirgeorge
author_rank: Contributor
timestamp: September 25, 2020, 06:19:16 am
content: Are these sensors ultimately interchangeable with anything? I need it to be surface mounted and compatible.
SONY IMX307 Video Microscope !Any Help Would Be Great! - Page 1
Forum section: electronics / beginners

author: TecnoPlay
author_rank: Newbie
timestamp: July 15, 2023, 08:33:35 am
content: Good day to all..Am having problem with my Microscope that I just Purchase,, first day worked perfect had no problems at all.. little ajustment that allsecond day worked purfect all good was using the mouse to ajust little focus end brightness on the screen out of the blue menu started to froze upMicroscope was showing on screen only menu option were kinda froze so I unplug the power cord, plug it back in end Microscope never out put againno video only get a red light never goes from red to blue , but now its red no displayWas purchase on alliexpress it worked really great the first time i had no problemMenu froze end that was it,, never worked againany tips or tricks on what can be the problem tested on diferent monitor nothing change power cord nothing new hdmi cable nothing am kind out of optionis there a way to do a hard reset !!!Pm tips would be great.. thanks

author: LinuxHata
author_rank: Frequent Contributor
timestamp: July 15, 2023, 09:44:55 am
content: It looks like a power supply issue. Have you tried to swap your AC adapter?

author: TecnoPlay
author_rank: Newbie
timestamp: July 15, 2023, 11:56:39 am
content: yes i did, also has a Type C port were i can use alternative power source.. same as always,,,

author: perdrix
author_rank: Frequent Contributor
timestamp: July 15, 2023, 12:04:23 pm
content: Return to vendor as faulty
Sony TA-FB930R: Bias current can't be set high enough(?) on one channel - Page 1
Forum section: electronics / beginners

author: klausman
author_rank: Regular Contributor
timestamp: March 29, 2025, 07:38:34 pm
content: So I have a Sony TA-FB930R that I replaced one output MOSFET on. The manual says that the test point for both channels (warmed up, no signal, no load) should be ±10mv. On the left channel, I can do that just fine. But even riding the amp hard for 10m (50% load through power resistors), I can't get the reading to go higher than 6.5mV or thereabouts. I figure "can't set it high enough" is better than the opposite, but....Now the question is whether a) that's a problem that needs solving and b) if so, how to solve it. I haven't done THD measurement since I don't own that kinda gear.My good Mexican friend Service Manuel is attached.

author: TimFox
author_rank: Super Contributor
timestamp: March 29, 2025, 07:46:14 pm
content: What audio gear do you have?Perhaps a DSO with FFT?

author: klausman
author_rank: Regular Contributor
timestamp: March 29, 2025, 07:51:11 pm
content: Quote from: TimFox on March 29, 2025, 07:46:14 pmI have a Rigol MSO5xxx (with all the bits), but I am not sure it would be up to snuff for this kinda stuff. The FFT functionality seems woefully coarse-grained if I only sweep 10Hz-20kHz. (Or I am using it wrong).

author: TimFox
author_rank: Super Contributor
timestamp: March 29, 2025, 07:56:25 pm
content: Quote from: klausman on March 29, 2025, 07:51:11 pmAs a quick check, if you have a decent generator for 1 kHz, you could scan from 500 to 5000 Hz and see the fundamental and at least the 2nd and 3rd harmonics.First check the generator itself, then the amplifier output.Obviously, one could get better results with a dedicated distortion analyzer.The old rule of thumb for an oscilloscope measurement was that 5% THD was visible on the trace itself.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 30, 2025, 04:38:18 pm
content: Dc measurements between channels, offsets to uV, assuming replacement part was a match to its counterpart.If not, both should have been replaced.Jeff
Sop to Dip adapter sockets minimum universal set - Page 1
Forum section: electronics / beginners

author: VSV_electron
author_rank: Regular Contributor
timestamp: February 28, 2023, 05:00:38 pm
content: Hello, I would like to get a minimal set of SOP to DIP adapter sockets that would cover most common SOP packages (serial flash etc.).I'm talking about these:https://aliexpress.com/item/32811287323.htmlFor instance, for 1.27mm leads pitch can I get an adapter for SOP24 that will cover smaller lead count ICs? That is SOP16/14/8 ?I know the packages differ in width but I wouldn't like to get too deep into investigation of various options at this point (I sort of want to get a few adapter sockets for a quick start).I'm planning to use the adapter(s) for testing ICs and programming.I consider the following scenario:I've got a bunch of SOP24 MAX7221EWG (7.6 mm package width) and also serial flash SOP8 W25Q32BV (5.2 mm package width)...... and as I'm writing this I see where I could probably go wrong with my uneducated assumptions...It looks like the SOP packages get progressively larger in width with the increase of the leads count and it apparently means that one cannot get away with some sort of the universal adapter socket.Am I correct on this?

author: Benta
author_rank: Super Contributor
timestamp: February 28, 2023, 09:48:11 pm
content: If it's standard 1.27 mm pitch SO types, you'll just need two:SO-16 (will cover SO-8, SO-14 and SO-16)SO-28 (will cover SO-16W, SO-18, SO-20, SO-24 and SO-28)Cheers.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 01, 2023, 12:01:45 am
content: Here's a link to the 3M Textool sockets. Scroll down to the SOIC sockets (p. 24). 3M offers 2 widths: 0.150" and 0300" width. There are inexpensive Asian copies that seem to copy that trademark. The pinout is a little different from standard DIP, so you may want/need an adapter board. Easy to make.https://multimedia.3m.com/mws/media/351660O/3mtm-textooltm-test-and-burn-in-socket-catalog.pdfI have the 8-pin, 3M version, my first. It is soldered to a DIP conversion board. Useful and works well. I also have a couple of the Asian knockoffs of the DIP ZIF sockets that also work.
Sorry, but another neophyte bench power supply question - Page 1
Forum section: electronics / beginners

author: Jimmy the Squid
author_rank: Regular Contributor
timestamp: September 14, 2012, 12:34:02 am
content: So, I have decided to purchase a new bench power supply to complement my existing finely handcrafted model (cheap Elenco kit). I'm looking for a digital one with some bells and whistles, but I have a question since I am fairly new to this sort of thing. Don't worry though - the question isn't "what should I buy?" Hopefully, it isn't a dumb question.My question is: on the power supplies with separate controls and displays for voltage and current, is it safe to assume that the current display will show the current being drawn, or is that a feature on only high end models? If it is the latter, what key words should I look for in product descriptions that would indicate the presence of an ammeter function?Essentially, I'm thinking that feature is so useful, I would pay a premium for it, and conversely, I would be sad of what I bought did not have it.Thanks!

author: TriodeTiger
author_rank: Regular Contributor
timestamp: September 14, 2012, 01:16:18 am
content: You'd usually set the current limit and the display will change from x to y. After a small timeout current monitoring will again be displayed, as the limit is useless information to persist (unless you're forgetful, YMMV).QuoteThis is easy to implement on a cheapie micro, and would otherwise make the second display a pointless added cost.Alexander.

author: robrenz
author_rank: Super Contributor
timestamp: September 14, 2012, 12:32:50 pm
content: IMO if it has separate dedicated displays for both current and voltage they will show the voltage and current being supplied. If you are in current limit or voltage limit it does not matter it will show what is actually being supplied.Whatever you do make sure both voltage and current have either ten turn pots or coarse and fine adjustments.

author: Jimmy the Squid
author_rank: Regular Contributor
timestamp: September 14, 2012, 05:43:10 pm
content: Thanks for the input. I did think that it would seem pretty silly to have a panel meter for amps, and then only have it be used for setting the current limit. But I read the August 9 review for the Mastech 3005f-3 on amazon that made me wonder. (This isn't what i am buying, but it is what sparked the question).http://www.amazon.com/Mastech-TRIPLE-LINEAR-SUPPLY-HY3005F-3/product-reviews/B004ISD7T6/ref=dp_top_cm_cr_acr_txt?ie=UTF8&colid=2IBBR556BZ67P&coliid=I2NR7NRO2LZ7FM&showViewpoints=1Thanks for helping me clear it up!

author: T4P
author_rank: Super Contributor
timestamp: September 14, 2012, 10:48:22 pm
content: Quote from: Jimmy the Squid on September 14, 2012, 05:43:10 pmUnless you wanted to be a smartass and rig a DMM up ...
SOT-23-8 for Eagle - Page 1
Forum section: electronics / beginners

author: ARGLaser
author_rank: Contributor
timestamp: December 06, 2012, 04:36:43 am
content: Hey everyone,I'm using Eagle to make a PCB and I have an ADC in a SOT-23-8 package. I can't find anything with the included eagle librarys, and I can't find anything from searching on Google. Can someone point me to a library with a SOT-23-8 device so I can use it in my circuit?Thanks-ARG

author: ju1ce
author_rank: Regular Contributor
timestamp: December 06, 2012, 10:35:18 am
content: You might as well make the footprint yourself. Sooner or later you need to make another one and it doesn't take very long if you already know how to do it.

author: LEECH666
author_rank: Frequent Contributor
timestamp: December 06, 2012, 10:53:36 am
content: Quick google search revealed the following:maxim.lbr (Device MAX4337.DEV / SOT23-8L.PAC)Result was in German tho.Hope that helps.Cheers,Florian

author: ARGLaser
author_rank: Contributor
timestamp: December 06, 2012, 06:04:27 pm
content: Quote from: ju1ce on December 06, 2012, 10:35:18 amIdeally I would like to be able to do this but I haven't been able to find a good tutorial on how to do it.Quote from: LEECH666 on December 06, 2012, 10:53:36 amI found that German result as well, but there was no download link so far as I could see.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: December 06, 2012, 08:48:34 pm
content: Check out my tutorialslinked here.Creating parts is actually pretty simple once you have the process down - way faster than searching for a footprint.One hint: Be sure to use whatever units (imperial or metric) the part was designed in when creating footprints. Rounding errors add up fast! The attachment shows pads that should be on the same pitch; notice how quickly the error adds up when using converted measurements.

author: IceKiller
author_rank: Newbie
timestamp: December 06, 2012, 08:48:55 pm
content: try this onehttp://domos2010.googlecode.com/svn-history/r8/trunk/maxim.lbrprobably the right one..

author: hlavac
author_rank: Frequent Contributor
timestamp: December 06, 2012, 08:54:21 pm
content: It is really easy to make footprints in Eagle once you find out what all the different layers are for.You will want to make your own anyway, many of the supplied footprints don't even pass the DRC because of solder mask overlapping pads etc.

author: ARGLaser
author_rank: Contributor
timestamp: December 06, 2012, 10:13:39 pm
content: Quote from: IceKiller on December 06, 2012, 08:48:55 pmThat's it, thanks!Quote from: Jon Chandler on December 06, 2012, 08:48:34 pmI'll check that out in the future, I am likely to need this again
sot23-3 identification needed. AZ9V - Page 1
Forum section: electronics / beginners

author: whitevamp
author_rank: Regular Contributor
timestamp: May 31, 2017, 06:23:07 pm
content: I am trying to identify this transistor and I am having no luck finding it.the AZ9V 14 part (Q5)

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 31, 2017, 06:28:09 pm
content: A9ZV, not AZ9Vhttp://www.vishay.com/docs/70835/si2309ds.pdf

author: whitevamp
author_rank: Regular Contributor
timestamp: May 31, 2017, 06:36:20 pm
content: yeah trans posed those 2 numbers there.and thankx.
sot23-6 power management CHIP identification - Page 1
Forum section: electronics / beginners

author: NickGreece2025
author_rank: Newbie
timestamp: April 27, 2025, 11:43:05 am
content: Hello EEVbloggers,I am going through a repair of a portable 2-cell device (2x3.2V LiFePO) and I am having deficulty in identifying a sot23-6 chip in the power management of the cells. I am actually trying to understand the principle of operation, as regards this section.I attached a schematic and a photo of the board.I would appreciate it if anyone could give me some direction about the chip model/number since i didn't manage to find anything similar around.Thank you all in advance for your help.Be well.

author: Fraser
author_rank: Super Contributor
timestamp: April 27, 2025, 01:50:24 pm
content: It is marked “Q10” so you are looking at a transistor rather than an integrated circuit.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: April 27, 2025, 02:01:42 pm
content: The BQ29209 IC datasheet helps to identify what this component is.https://www.ti.com/lit/ds/symlink/bq29209.pdf?ts=1745762235736&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ29209It appears to be a dual MOSFET. See figure 11 on the datasheet. (Screen capture attached)Fraser

author: wraper
author_rank: Unknown
timestamp: April 27, 2025, 02:06:38 pm
content: PCB layout suggests dual mosfet.

author: Fraser
author_rank: Super Contributor
timestamp: April 27, 2025, 02:15:09 pm
content: A well lit and focussed image of the MOSFET markings may assist in identifying it. I know you have provided the characters already but an image can sometimes tell us more.Fraser

author: NickGreece2025
author_rank: Newbie
timestamp: April 27, 2025, 02:51:54 pm
content: Dear Fraser and Wraper,you are correct. Actually on the schematic i drew, the 47Ω must be RCB_EXT and the 4.7ΚΩ the RCLAMP resistors respectively, on the BQ29209 schematic. So yes, actually I should look for a dual mosfet (N+P) sot23.I will give it a try, thank you a lot indeed for your guidance.
Sound Data Transmit from Arduino to PC - Page 1
Forum section: electronics / beginners

author: pinkybri
author_rank: Newbie
timestamp: May 17, 2021, 10:14:04 am
content: Hello everyone, I'm a total newbie and I need help with my project. I'm trying to build an Arduino-based digital stethoscope and it has to be wireless. I'm using MAX4466 and thinking to use ESP8266 for wifi communication. As far as I've done, MAX4466 is working and I can see data on serial port but by a cable input to PC. However, I cannot figure out how to use ESP8266 for transmitting sound data, that have taken from MAX4466, to PC. What can I do about it? Since I'm pretty unfamiliar with those kinds of electronics topics, your suggestions are very important for me, thanks in advance.Or if you have any other suggestions for transmitting data (it can be bluetooth maybe other than wifi), I would like to get any help.

author: Zipdox
author_rank: Regular Contributor
timestamp: May 17, 2021, 06:56:16 pm
content: The ESP8622 ADC is only 10bit, and it has a limited sample rate. If you want to capture decent quality audio you'll want to use an I2S (not to be confused with I2C) ADC. A better solution would be to use an I2S microphone module directly, like the INMP441.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: May 18, 2021, 06:02:53 am
content: ESP32 has I2S. It also has Arduino library support.
Sound system - Page 1
Forum section: electronics / beginners

author: Megatech1966
author_rank: Newbie
timestamp: December 23, 2023, 11:54:02 am
content: Is 5 to 24 volts ac normal for a line input on a sound system?

author: Circlotron
author_rank: Super Contributor
timestamp: December 23, 2023, 12:16:57 pm
content: 1 volts RMS is more like it.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 23, 2023, 01:32:27 pm
content: it depends if it as an high voltage input, i did saw in the past some commercial stuff having high voltage signal inputBUTyour description is to vaguemodel, brand, what is driving the unit etc ... photos

author: themadhippy
author_rank: Super Contributor
timestamp: December 23, 2023, 01:36:56 pm
content: could be 100mV or it could be 10V,theres no official standard as far as i aware

author: CaptDon
author_rank: Super Contributor
timestamp: December 23, 2023, 01:58:45 pm
content: There is one specific case where this could be normal although it is very dated. Sunn in particular made 'booster amplifiers' where the speaker output voltage (28.5vrms @ 100w) from an instrument amplifier (guitar etc.) was daisy chained to the booster amp input which drove a speaker stack and this could continue to be multiplied down the line. The booster amp output voltage was the same as the input voltage although the current was boosted to drive the speaker stack. Other manufacturers copied this idea and there was also a similar amplifier offered by Seeburg for daisy chaining jukebox speakers in large clubs. The Sunn booster amps did have a gain control so you could go from 0 (no sound) to a slight gain over the input signal although 'unity gain' would be the normal setting. Almost as obsolete is the '25 volt line' which was largely replaced by the 70.7 volt distribution system.

author: donlisms
author_rank: Frequent Contributor
timestamp: December 25, 2023, 06:14:52 pm
content: Your question does not provide enough information to be able to answer it very well. Are you trying to find out if an existing system is working normally? Or if something will work if you try it? What devices are you trying to connect?When you say "line input", if you mean it in the technical sense, for example what would be in the specifications, then it will typically have a maximum of... perhaps +12 dBu (3 volts) to +20 dBu (7.75 volts).24 volts would be about +30dBu, which would definitely be way above normal, and no normal line input could handle it.Speaker outputs are commonly put through a properly-configured direct box, which will pad the signal down appropriately (often through a very simple resistive divider).
Soundcraft mixer power supply question - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: February 03, 2025, 07:12:20 pm
content: Hi,I'm trying to make a new power supply for a soundcraft console based on a schematic I found online.I made a PCB with the +-17v and +48v rails.The problem is that my PCB outputs +-10V on what should be +-17 and about 6.5V (??) volts on the +48V rail.My unregulated DC is about 24v instead of the 26V which is shown on the schematic.Could that be the problem?Can I modify the circuit somewhat to obtain +-17V if that's the case?For some reason I doubt that it's the unregulated DC that's at fault here but then again I have no idea how this circuit works.I triple checked the circuit but can't find anything wrong..I still need to check the +48V rail because that's way worse than the +-17V one..I attached the schematics and the pdf where I found it.

author: CaptDon
author_rank: Super Contributor
timestamp: February 03, 2025, 08:48:04 pm
content: What transformer are you using? Show the transformer wiring and voltages and your bridge rectifier circuit and filter capacitor network. If this is a correct Soundcraft schematic then it should work with no mods. What is the input supply voltage to your 48 volt circuit. It would have to be around 56 or so? We can't tell anything from the information you provided. If the schematic is accurate and everything not shown on the schematic is in proper order then it should all simply work. Why are you building a power supply? What happened to the original? What does your supply do with no load?I would have made real sure my power supply was right on the money before connecting it to a console and trashing a decent mixing desk. I think I recently saw a SoundCraft rack mounted console power supply for sale on Ebay.

author: belzrebuth
author_rank: Frequent Contributor
timestamp: February 03, 2025, 09:15:18 pm
content: Ι'm using a toroidal transformer that provides dual 18vac so I wired it as a center tap and I got 18-0-18 vac which gives me 24V unregulated DC after the bridge rectifier and capacitor network.The same transformer has a secondary winding for the phantom power which gives me 50Vac which translated to 67V unregulated DC.I didn't try the power supply in the console of course, I got the console without a power supply but I had a suitable transformer a rack enclosure and some time to roll my own PCB that's why I decided to do it.I attached my schematics as well which were not meant to be seen by anyone else so they're not that clear in a sense that some wires are labeled as "EEE" or "CCC" for lack of a better name.Hopefully they're clear enough to spot any errors..

author: belzrebuth
author_rank: Frequent Contributor
timestamp: February 04, 2025, 08:35:32 am
content: I figured it out.The +48 rail had a dodgy 11V zener I replaced it and it came life.One the bipolar 17V rail I was an idiot and placed the BD135/BD136 backwardsso no wonder it would not work.Now I need to load test it..fingers crossed!
Source Code Analog Devices CN0359 - Page 1
Forum section: electronics / beginners

author: alnstn10
author_rank: Contributor
timestamp: July 05, 2022, 02:55:03 am
content: I've downloaded the source code for the analog device eval cn0359 eb1z, but I'm still confused about the location of the main program, because if you look at the folder there are lots of source code for each feature of the analog device eval cn0359 eb1z.do I have to compile all the source code? If so, how do you compile it?(source code in cpp format)source code links:https://wiki.analog.com/_media/resources/eval/user-guides/circuits-from-the-lab/cn0359/cn0359-sourcecode-reva.zip

author: ledtester
author_rank: Super Contributor
timestamp: July 05, 2022, 02:07:07 pm
content: In the Release directory there is a makefile. You'll also find a pre-compiled CN0359.bin file there.Flashing instructions may be found here:https://wiki.analog.com/resources/eval/user-guides/circuits-from-the-lab/cn0359#how_to_download_binary_firmware_to_the_cn0359As for the steps to recompile the firmware, the best I could find is:https://wiki.analog.com/resources/eval/user-guides/circuits-from-the-lab/cn0359#software_development_environmentwhich only lists the various toolchain components used. The files might already be organized as an Eclipse project and invoking the recompile action in Eclipse might just work.
SOURCE CODE of BSIDE01 : WHERE I CAN DOWNLOAD IT ? - Page 1
Forum section: electronics / beginners

author: simbeault
author_rank: Newbie
timestamp: April 26, 2024, 04:58:14 am
content: I would like to see if i can add him a function generator.Edit by gnif to remove the email address used in the last edit message.

author: pcprogrammer
author_rank: Super Contributor
timestamp: April 26, 2024, 05:19:23 am
content: I don't think you can find it unless it has been reverse engineered.Another bit of advice, ask a moderator to change your user name. Having it be your email address is not a very good idea. You can click the "Report to moderator" link in the lower right corner of your post.

author: gnif
author_rank: Unknown
timestamp: April 26, 2024, 07:59:21 am
content: I have done this anyway.
Source for cheap solenoids - Page 1
Forum section: electronics / beginners

author: jerzmacow
author_rank: Newbie
timestamp: June 16, 2012, 08:56:56 am
content: Hello!I'm building a player piano that will accept MIDI, among other things. Right now the hardest part has been sourcing the solenoids. Right now I'm looking at the ones Sparkfun has:http://www.sparkfun.com/products/11015Since I need about 90 of them, Sparkfun would not be cheap. I checked Jaycar, Digikey and Mouser to no avail.I'm hoping someone knows of a more OEM supplier that would be in the sub $3 range.Thank you!

author: amyk
author_rank: Super Contributor
timestamp: June 16, 2012, 12:17:06 pm
content: http://www.alibaba.com/product-free/127516786/Chinese_custom_boiler_or_toys_usage.htmlThis appears to be the same manufacturer with a slightly different (smaller) model.$0.45-0.60/piece, but you need to order 1000 of them...http://www.ec21.com/product-details/Linear-DC-Frame-Actuater-Solenoid--4591245.htmlThe exact same model, RMB 4.50 which still <$1. Also 1000 MOQ.
Source for heat sink extrusions - Page 1
Forum section: electronics / beginners

author: watchmaker
author_rank: Unknown
timestamp: February 29, 2024, 01:02:46 pm
content: Since I know how to cut and tap metal, I would prefer to buy the raw extrusions used for rear mounted heat sinks.Has anyone sourced these and is willing to share the vendors?Thank you.

author: ifonlyeverything
author_rank: Regular Contributor
timestamp: February 29, 2024, 01:35:44 pm
content: https://www.heatsinkusa.com/?

author: jonpaul
author_rank: Super Contributor
timestamp: February 29, 2024, 01:56:16 pm
content: thermalloy

author: CaptDon
author_rank: Super Contributor
timestamp: February 29, 2024, 01:57:13 pm
content: It's been too many years since I did B.O.M.'s but Avvid and Thermalloy come to mind?? I think we bought ours in 36" or 48" lengths and our machine shop did the rest. The 'Total Landed Cost' using union labor in the machine shop probably exceeded just having the heatsink extruding company do the work for us!! They will charge for the CNC setup, but if you are going to run 10,000 pieces it's worth the cost.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: February 29, 2024, 02:18:53 pm
content: Quote from: ifonlyeverything on February 29, 2024, 01:35:44 pmSeconded - they will also do the machining for you.

author: coppice
author_rank: Super Contributor
timestamp: February 29, 2024, 02:27:57 pm
content: If you need high performance, I'd recommend working with a supplier specifically in the heat sink market. I vaguely remember, from many years back, finding the thermal resistance of various alloys and extrusion methods has a wide spread, and you don't want to find you have the wrong one. Treating the surface where the heat source clamps on can also change performance a lot. You can get the oxide stripped, and a combination of platings applied to end up with a copper surface (you can't plate copper directly onto aluminium. I assume there are multiple layers in a CCA cable, too). Its takes only a surprisingly thin coating of copper to help spread the heat info the heat sink, and reduce hot spotting.

author: mag_therm
author_rank: Frequent Contributor
timestamp: February 29, 2024, 02:45:10 pm
content: If needing just a few for hobby, there are some $4 ones here:https://www.sphere.bc.ca/oldsite/test/stuffday.html#audioTo find on the long page: ctl >F "Blank Heatsinks"

author: jmelson
author_rank: Super Contributor
timestamp: February 29, 2024, 04:28:02 pm
content: I have bought bulk extrusions from Aavid in 6 foot lengths.Jon

author: CaptDon
author_rank: Super Contributor
timestamp: February 29, 2024, 06:47:31 pm
content: Jmelson, good catch on my spelling Avvid vs. Aavid!!! Cheers mates!!

author: watchmaker
author_rank: Unknown
timestamp: February 29, 2024, 11:04:12 pm
content: Thank you all! I may have follow up questions after I study the website. Kind of confusing.