hybridfree/eevblog-posts huggingface dataset:
desoldering gun with 3d printer nozzle - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: April 26, 2014, 11:50:55 pm
content: Convinced not to spend 100$ or more for a vacuum-desoldering tool. Bought this 12V/1A sparcfun vacuum engine. Though I find the end price bit expensive, sparkfun is among few US and A companies that deliver to Bel and gium for a fair 8$! Bought the Aoyoua C005A heater with nozzle, apply temperature controlled 24V and booom... stuff should work... Well still some design detail how to attach the nozzle to the heater, but should not be so difficult. The problem would be to attach the sucker pipe to the heater due to thermal problems, but this teflon pipe/tubing should help. Besides that the pump is always available on the desk for other purposes. (like inflating balloons if once every 10 years I would be in the mood, or inflating the bicycle tires)in my solution for vacuum desoldering the big question was to combine a ceramic heater with nozzle that is attached through a pipe to a vacuum pump. I find certain devices or solutions ridiculously expensive. This is kind of lego for 12 years old child brain capacity to combain a heat source with ah vacuum source and apply to a fix point to suck fluid solder.What i wonder however if all this aoyoua heater and nozzle could not be replaced with the so available 3d printer nozzle/head etc storry, like in the link above: Well 20$ is alreado toooo much for it... individual parts could cost max 12$.Anybody already used this head/block/ceramic heater combination?http://www.ebay.com/itm/Heater-Block-Nozzle-throat-Extruder-Nozzle-Heater-Thermistor-3D-Printer-DIY-Kit-/171126555685

author: MacAttak
author_rank: Unknown
timestamp: April 27, 2014, 02:19:50 am
content: 3d printer heads like the one you link to typically have a thermistor that is only rated to slightly above 300C. You would need to find a higher temp thermistor or use a thermocouple.The nozzle opening (typically 0.4mm or so) is probably much too narrow and you'd want to find a nozzle with a larger opening. Or perhaps drill out the 0.4mm hole to something larger.Extrusion heads like that are designed to maximize heat in the central block - not at the nozzle tip. So you'll actually need to run it slightly hotter than a soldering iron would be.You will have a difficult time seeing the workpiece behind the heating block / cartridge heater. Also, the thick heater wires typically protrude from the side, making it even more difficult to see around.Lastly, the nozzle will come up to working temperature FAR more slowly than a real soldering iron would. A soldering iron will only take a few seconds to reach reflow temp. An extrusion nozzle will take a few minutes unless you power it VERY aggressively, which will make it very hard to control the overshoot.
Desoldering pump - Page 1
Forum section: electronics / beginners

author: LagStorm
author_rank: Newbie
timestamp: September 11, 2022, 05:56:21 pm
content: Hello,I would like a desoldering pump, I found the ZD915 and the Pro's kit SS-331H, which one do you recommend?Thanks

author: --Oz--
author_rank: Regular Contributor
timestamp: September 11, 2022, 06:27:43 pm
content: You should give links to the equipment and the application use.I personally hate these pumps, seems every time you go to use them they require maintenance (maybe because multiple people use them).I use the AS196 SILVERSTAT SOLDAPULLT.

author: rooppoorali
author_rank: Regular Contributor
timestamp: September 14, 2022, 02:53:55 pm
content: This review may interest you.https://www.galvinpower.org/best-solder-suckers/

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 14, 2022, 03:32:09 pm
content: about 8 years back i bought this and still working amazing, its very cheap electric pump very easy to use and way more efficienthttps://www.aliexpress.com/item/4000473959990.html
Desoldering SlimStack - 0.4 picth - Page 1
Forum section: electronics / beginners

author: poz1
author_rank: Newbie
timestamp: April 01, 2019, 02:51:59 pm
content: Hello everyone!I am working on my first custom board and being a Software Engineer does not help muchMy first obstacle is that I need to connect to another board using a FlexCable with a Molex SlimStack plug on it.I was able to find the part number of the receptacle (500024-5009) but it is discontinued and hard to find.I am still working on the prototype so I would need only a few of them (that doesn't help).So my options are:1) change the plug on the flex (is it even possible without destroying everything?)2) desolder the connector from the old board and reuse itWhat do you think about these options? Are they feasible? And waht would be the best approach? Hot air or iron?Thank youIn attachment pics of the connectors
Desoldering station - Page 1
Forum section: electronics / beginners

author: jheatac
author_rank: Regular Contributor
timestamp: September 22, 2024, 10:30:30 pm
content: I have used a Hakko FR301 for a few years.I don't really have any issue with it. I was just curious if there is much of a difference between that and a bench top version such as the FM-204
Desoldering station & rework station - Page 1
Forum section: electronics / beginners

author: coolyota
author_rank: Contributor
timestamp: December 07, 2019, 11:35:17 am
content: Hello,I am currently studying electronics, would like to purchase desoldering station and a rework station. My budget is small. My search has narrowed to:Rework station:https://core-electronics.com.au/hot-air-rework-300w.htmlDesoldering station:https://www.altronics.com.au/p/t2065-micron-90w-vacuum-desoldering-station/Would both of these suit me? I don't have much experience using either of them, keen to learn SMD soldering and a desoldering station for those times I need to desolder through-hole.Thank you.

author: Saskia
author_rank: Super Contributor
timestamp: December 07, 2019, 11:47:26 am
content: get a decent hot air station, it is easy to desolder through hole components using hot air and a decent manual desoldering pump. it is also faster and if done correctly does not damage the traces.

author: interoth
author_rank: Contributor
timestamp: December 07, 2019, 03:39:47 pm
content: Following on from saskia, for hobbyist/student level I would recommend this or something equivalent. Expected something naff but it's turned out to be a real workhorse.https://www.ebay.co.uk/itm/2in1-SMD-Soldering-Iron-Station-Hot-Air-Gun-Rework-Welder-Desoldering-Tool-862D/153646417412

author: Jwillis
author_rank: Super Contributor
timestamp: December 07, 2019, 11:38:21 pm
content: Vacuum desoldering stations are more for high volume production lines and not really necessary for the budgeted hobbyist. You have to ask yourself if it's really worth the money or can you do with a 20 dollar manual pump.

author: coolyota
author_rank: Contributor
timestamp: December 08, 2019, 12:44:47 am
content: Quote from: interoth on December 07, 2019, 03:39:47 pmThanks Saskia/interoth. I'll look into the Yihua 862D.Quote from: Jwillis on December 07, 2019, 11:38:21 pmTrue, good question to answer. I'll stick with a manual solder pump then and buy a hot air rework station instead.
Desperate - identifying smt component - please help. - Page 1
Forum section: electronics / beginners

author: honasvocas
author_rank: Newbie
timestamp: October 14, 2021, 07:36:47 am
content: Hello,Ive been trying to identify a smd component in friend´s shaver that Im repairing.It seems to be a voltage regulator in SOT89 (according to measurements). As it has burnt I cant really read all of the markings on the component.It seems it begins with 2 0 X "delta marking" 6. (x represents the one I can not read, there may be 2 markings as well).Shaver is a Braun Syncpro 7785, of which I have not found a service manual online. Shaver has 12V 400mA charger and two internal 1.2V NiMh batteries.Any advice is highly appreciated.I include a photo.

author: honasvocas
author_rank: Newbie
timestamp: October 16, 2021, 04:41:25 pm
content: bump

author: Manul
author_rank: Super Contributor
timestamp: October 16, 2021, 06:05:09 pm
content: If you are desperate, post:1. Picture where components are visible good2. Pictures of both sides of PCB where tracks are visible good (try light from behind)3. Mark battery, motor and any other connectionsIt is likely easier to understand what it does and replace with generic part then to find this exact one.

author: Gyro
author_rank: Super Contributor
timestamp: October 16, 2021, 07:07:44 pm
content: Hint: Friends don't offer to repair friends' shavers (particularly*) - they are rarely grateful enough to justify the time (and time constraint), organic debris, and hassle.Edit:*This probably applies to all 'personal care' items.

author: Johnny10
author_rank: Frequent Contributor
timestamp: October 16, 2021, 07:37:40 pm
content: If it is a good friend why not save yourself the trouble and buy them a new one?For 25-30 dollars it is hardly worth the trouble.

author: Terry Bites
author_rank: Super Contributor
timestamp: October 17, 2021, 10:36:25 am
content: What ouput do you expect from the regulator, Volts, Amps? Find a replacement, job done.https://www.mouser.co.uk/c/semiconductors/power-management-ics/voltage-regulators-voltage-controllers/ldo-voltage-regulators/?package%20%2F%20case=SOT-89-5
Destination initiated handshaking vs source initiated handshaking.... - Page 1
Forum section: electronics / beginners

author: shivajikobardan
author_rank: Contributor
timestamp: October 22, 2021, 06:27:33 am
content: In destination initiated handshaking-:1) Disable ready for data2) Disable data validThat means first destination says "I received data totally". Then source stops sending data.In source initiated handshaking-:1) Disable data valid2) Disable data accepted.That means first source stops sending data, then destination says "I have received data totally"Source-:https://cvbl.iiita.ac.in/sks/coa-files/lectures/Lec_11_IO.pdfWhy are these 2 different order from each other?

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: October 23, 2021, 05:57:19 am
content: Think about what would happen if you changed the order.E.g. in destination-initiated, wrong order: data valid could be deasserted before the receiver has signalled that it has received it (by deasserting ready for data).In practice, this kind of asynchronous system with multiple signal lines is rarely used today. The closest analogy is "clock stretching" in I2C. In most protocols commonly used in electronics, such as SPI, UART, and the various parallel systems (RAM, displays, etc.), the designer makes sure that the clock speed is suitable for both master and slave.Does that answer your question?

author: shivajikobardan
author_rank: Contributor
timestamp: October 23, 2021, 04:21:22 pm
content: I played a little with data and these 2 signals, and now I clearly get the flow. Thanks for your reply. It help me click the answer.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: October 23, 2021, 11:00:32 pm
content: Great!Sometimes you just have to learn stuff for the exam, and then you never use it again. But the principles can be important to understand. Another example of this isthe OSI model... nobody actually uses OSI, but we do use the model to describe networks.If you really want to get an advantage in the hiring process, and learn about real-world protocols, you can make your own devices with open source code and put your projects up on Github. That's how I got started. Just had a few Arduino clones, some peripherals, Dupont cables, breadboard, anda $10 24 MHz logic analyser.Good luck!
Detect the right LCD - Page 1
Forum section: electronics / beginners

author: mauros
author_rank: Regular Contributor
timestamp: December 19, 2017, 11:02:23 pm
content: Hi everybody,I must find a compatible LCD of thishttp://it.tinypic.com/view.php?pic=313ot3s&s=9#.WjmU0mvr11sThe parent company does not release spare parts !! Can you tell me how I can find a compatible one? In the original the abbreviation is SMMC12864 EA-00-SPChttp://www.datasheet4u.com/datasheet-pdf/ETC/SMMC12864/pdf.php?id=934845This is a graphical LCD Chip on Glass (COG), controller ST7565R,serial interface (SPI) and 128 x64 FSTN, but mine has 28 pins anduseful dimensions of mine are 50 mm x 35 mm x 4 mm.If someone can help me, I thank you in advance.Cheers !
detect whith pulse - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: April 24, 2018, 04:06:57 pm
content: In a Rigo ds1054z oscilloscope, as I use the shot option to detect the width of a given pulse value, the option pulse does not have the option is equal to a certain time <=> as if it had the 1052 rigol.
Detecting which component failed in laptop power circuit - Page 1
Forum section: electronics / beginners

author: Korime
author_rank: Newbie
timestamp: August 02, 2015, 09:34:33 pm
content: Laptop powers up from the battery but it does not from the charger and it doesn't charge the battery either.I have measured voltages on power circuit components (see in the attached image).http://postimg.org/image/wnd643gnb/Or for better resolution, download pdf schematic file (page 6).https://www.scribd.com/doc/273197386/Toshiba-Satellite-C650-655-Motherboard-Inventec-SchematicIn "blue" are voltages measured when only charger is attached. In "green" are voltages measured when only battery is attached. In "italic" are voltages that prevail when both charger and battery are attached."6-7V" means that multi-meter is reading unstable voltage which goes from around 6 to around 7 volts up and down. Does this indicate malfunction and of "Q6003"?If not, which component/s are not working properly and need replacing?Update: I have replaced Q6003 and everything stayed the same, so it's not that component.

author: CaptainObvious
author_rank: Contributor
timestamp: August 03, 2015, 12:58:25 am
content: Maybe I skipped over it while I was reading, but I didn't see where you've tested the laptop charger? (unless this is what you mean by circuit components)More often than not the charger will die before your charging circuit, 7/10 times I get a laptop that won't charge in my shop it's due to a faulty laptop charger. (2.99/10 would be for the DC Jack replacements, don't think I've come across a faulty charge circuit yet)
Determine Diode or Zener without destroying diodes? - Page 1
Forum section: electronics / beginners

author: AlfBaz
author_rank: Super Contributor
timestamp: March 09, 2015, 01:14:49 am
content: I have a board with a heap of old style colour banded diodes. Unfortunately none of the colour codes I have found on the net seem to line up with the ones I have.Tracing the circuit out, some of these diodes have to be zener's for the circuit to make any sense or maybe I've just traced it out wrong.Are there any tests that can be carried out to tell them apart without destroying the ones that are diodes?

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 09, 2015, 01:37:02 am
content: It actually won't hurt a regular diode to cause it to break down in the reverse direction as long as you restrict the current to something reasonable. A 100K resistor in series with your power supply, assuming it's somewhere below 100v, should do nicely for sorting which are zeners and which are regular diodes.

author: Ian.M
author_rank: Super Contributor
timestamp: March 09, 2015, 01:50:44 am
content: Additionally, Zeners over 50V are fairly rare and most non-exotic silicon diodes are likely to be able to stand 50V so if you limit the supply feeding the series 100K resistor and diode under test to 50V you further reduce the risk of damage without loosing much information.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 09, 2015, 03:06:00 am
content: Yeah, just reverse bias it with some current (such as through a nice large resistor) and see what it clamps at.Note that zeners typically take a fairly generous current (mA+) to reach rated voltage, so you can easily misidentify a 4.7V part as 3.9V or something.Diodes not intended for zener duty typically break down in the 40V+ range (schottky being on the low side, PNs being on the higher side usually -- e.g. 1N4148 ~100V, etc.). They also may be sensitive to breakdown (i.e., causing... problems).RF diodes may have very small junctions (< 2pF CJO -- needless to say, not intended to handle much reverse bias current) and low breakdown voltages, so be careful if you suspect these.Tim

author: AlfBaz
author_rank: Super Contributor
timestamp: March 09, 2015, 01:50:55 pm
content: Thanks for all the info gentlemenThe board in question is an old MV105N "Precision DC Millivolt Standard", so rather than run the risk of "causing problems" I might just reassemble the unit and simply measure voltages across the "diodes" which, in conjunction with the schematic I've traced have so far, should give me the info I need.I have sent Krohn-Hite 2 emails asking for a quote for any info or documentation on the unit and they have not replied. It appears you have to be a youtube star to get a reply from these people

author: Electro Fan
author_rank: Super Contributor
timestamp: March 09, 2015, 04:05:56 pm
content: You can call Krohn-Hite and ask to speak with someone who is familiar with the specific product (old or new) that you are inquiring about. The tel # is on their web site. They are knowledgeable, helpful, and friendly.
Determine LCD Pinout - Page 1
Forum section: electronics / beginners

author: codingwithethanol
author_rank: Regular Contributor
timestamp: July 30, 2019, 11:16:45 am
content: Hey, I recently disassembled a clock radio that i don't need, and salvaged the LCD from it. I've gotten pretty far in figuring out how to drive it, but i'm at a loss as to what to try next.I connected each pin to an Arduino and sent an alternating pattern of high and low with the pin to test inverted, per this suggestion:https://electronics.stackexchange.com/a/56987Basically if you want to see which segments are connected to pin 5, you put pin 5 high and the rest low, then pin 5 low and the rest high, over and over.Here is the video showing the output cycling through test pins:Here is a gallery with easier on the eyes images of screen states 2-17:https://imgur.com/gallery/OwMvT1tState 1 is literally nothing. Also as you can see in the video, the cluster of icons at the bottom is on in every state, so I removed the cluster from every photo except the last one.I noticed that the "B" only appears in states 2 and 17, obviously pins 2 and 17 drive that segment but how do I handle this so that none of the other segments light?
Determine maximum current for a Class-D amplifier? - Page 1
Forum section: electronics / beginners

author: Faranight
author_rank: Unknown
timestamp: August 02, 2023, 05:32:46 am
content: Hello. I've never done audio before, so I am a bit puzzled by this one. I'm trying to dimension a power-limited DC-DC boost PSU on a DIY board for amono Class-D speaker amplifier. The audio IC will be powered by 12VDC and use an 8-Ohm 12W speaker. Assuming the volume is set to max, how does one determine the highest current that this IC can draw on its PVdd under worst operating conditions (i.e. max bass)? Is there a good way to estimate this parameter or is geting an eval board and measuring it the only way? The datasheet says that the IC has an internal current limit of 2A. However, using the Ohm's law on the supply voltage vs speaker resistance only results in 12 V / 8 Ohm = 1.5 A. The datasheet further states that this IC is a 10W amplifier, which means that it should draw a maximum of about 700 mA at its highest supply voltage of 14V (power = voltage * current).Excerpt from first page of datasheet:QuoteSo, am I correct to assume that a boost converter with a maximum output current of 1A at its worst operating conditions will be sufficient to power this audio IC at its peak current draw?The final board will be powered frombatteriessupercapacitors, so I have to determine the minimumbatteryvoltage where the boost converter can still deliver sufficient current.

author: tooki
author_rank: Super Contributor
timestamp: August 02, 2023, 02:31:19 pm
content: The explanation is that the ohms value of a speaker is itsimpedance, not itsresistance. The resistance (DC) is lower than the impedance (AC), so the maximum instantaneous current can be higher.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 02, 2023, 03:03:39 pm
content: Great article for you.www.edn.com/understanding-class-d-amplifier-power-supply-requirements
Determine output impedance using LTSpice - Page 1
Forum section: electronics / beginners

author: Aeternam
author_rank: Unknown
timestamp: November 21, 2016, 08:48:03 pm
content: I was clicking around LTSpice while reading up on Thevenin equivalent circuits and was wondering if it was feasable to determine Vthevenin and Rthevenin (read, output impedance) using the simulator. Turns out it's pretty straightforward:1. Determination of Vthevenin is easy. Capture the circuit with no load attached, then run an operating point analysis. Take note of Vout, this is Vthevenin (here: 15V)2. Determination of Rthevenin is not very complicated either. We know that, if we add a load equal to our circuit's output impedance, its output will drop exactly by half. So let's add a load to the circuit, make its resistance a variable, and probe Vout. The screenshots below show the result (plus the syntax for the parameter sweep). All you have to do now is find Vthev/2 (7.5V) on the chart and read off the corresponding Rthev (5k). Easy

author: Ian.M
author_rank: Super Contributor
timestamp: November 21, 2016, 10:45:36 pm
content: Simpler to short the output through a 0V voltage source to ground, do another .op and divide Vthevenin by the current through the short. (Its quite common to add a 0V source when you need to measure the current in a wire and there's no convenient single component to measure the current through.)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2016, 12:15:24 am
content: Two calculation methods:http://seventransistorlabs.com/Calc/Thevenin.htmlTim

author: Cerebus
author_rank: Super Contributor
timestamp: November 22, 2016, 01:39:35 am
content: Or you could use the ".tf V(Vout) Vin" spice directive which will directly tell you the output impedance.

author: danadak
author_rank: Super Contributor
timestamp: November 22, 2016, 01:42:36 am
content: Maybe I am missing something (usually am), just stim theoutput with a current source, plot V and V/Istim vs F, youwill have your Zout.Regards, Dana.
Determine read cycle speed of eeprom - Page 1
Forum section: electronics / beginners

author: Supreme
author_rank: Newbie
timestamp: November 29, 2016, 09:05:05 pm
content: Hi, I have this chip:https://4donline.ihs.com/images/VipMasterIC/IC/TOSC/TOSCS25929/TOSCS25929-1.pdf?hkey=EF798316E3902B6ED9A73243A3159BB0I want to dump its memory using programmer also i want to analyze it using oscilloscope/logic analyzer , what is the cycle speed Mhz/Sample rate of the devices in order them to work with this chip?If it is possible, please explain how you calculated the result.Thanks.

author: amyk
author_rank: Super Contributor
timestamp: November 30, 2016, 03:43:53 am
content: Look at page 5. This is a NAND flash, read and write cycles are internally timed and may vary in length depending on the age/wear on the blocks.

author: Supreme
author_rank: Newbie
timestamp: November 30, 2016, 06:07:28 pm
content: Which device can dump the contents of the NAND chip? and what its specifications should be?

author: amyk
author_rank: Super Contributor
timestamp: December 01, 2016, 03:33:45 am
content: Anything with enough I/Os... and is fast enough that you won't be annoyed waiting for it to finish reading. Even an Arduino will do it if you don't have anything else.http://hardcoreforensics.com/blog/2012/01/02/arduino-mega-direct-reading-of-a-nand-flash-memory-chip/
Determine smd 0805 capacitor value - Page 1
Forum section: electronics / beginners

author: ntec
author_rank: Newbie
timestamp: November 30, 2021, 08:37:18 am
content: I am trying to replace a shorted 0805 capacitor on my router that i tested with my fluke but how do i determine the value of it since there is no schematic. The capacitor is right beside the dc input jack of the router. I attached and circled in red the black capacitor on the board and also a pic of the cap removed. Don't know if it matters but the power info on the router label is 19v 1.75a

author: wraper
author_rank: Unknown
timestamp: November 30, 2021, 08:55:52 am
content: It's not a capacitor but ferrite bead an must have low resistance by design. So solder it back.

author: ntec
author_rank: Newbie
timestamp: November 30, 2021, 03:58:22 pm
content: Thanks, i'll solder it back.
Determining ability of MSP430FR6989 GPIO to source/sink current - Page 1
Forum section: electronics / beginners

author: Mattjd
author_rank: Regular Contributor
timestamp: October 16, 2017, 05:53:43 pm
content: Hey, I am using the MSP430FR6989 to control the duty cycle of an RGB led. I have the RGB cathodes connected to GPIO with the CCRx registers of Timer B multiplexed to those pins. I am connecting the common anode to the 3.3 supply of the GPIO. I am trying to figure out how to determine the typical current sink/source of the GPIO to determine the resistors that should be used between the cathodes and GPIO. The forward voltages of the RGB are respectively 1.8,2.8, and 2.8. I've been looking through this data sheet for a while now and am not finding what I am looking for.http://www.ti.com/lit/ug/slau627a/slau627a.pdf

author: ebclr
author_rank: Super Contributor
timestamp: October 16, 2017, 06:05:47 pm
content: This information is available on the datasheet, if you don't need a very bright rgb, This is a very low power cpu, target to be used with LCD, Datasheet says 2 ma MAX, If you want more use a transistorhttp://www.ti.com/lit/ds/symlink/msp430fr6989.pdf

author: Mattjd
author_rank: Regular Contributor
timestamp: October 16, 2017, 06:23:07 pm
content: What table did you view to find this on the datasheet?

author: viperidae
author_rank: Frequent Contributor
timestamp: October 18, 2017, 09:36:33 am
content: Look at page 48 and 49. By the looks of the graphs, output impedance is 15 to 20 ohms.3v in, 20mA out gives you about 1.75v on the output pin
Determining amplifier output power for different impedance loads - Page 1
Forum section: electronics / beginners

author: Robert.Adams
author_rank: Contributor
timestamp: June 25, 2014, 11:02:16 pm
content: Hello all,I'm looking into enhancing my music listening at work by incorporating a pre-amp and my Sennheiser HD580s into my cube life. The headphones are 300? with a maximum power rating of 80mW (Reference:http://headwize.com/?page_id=550).The source of the audio would be my Samsung S3 which uses a Wolfson WM1811 DAC to drive the headphones. This IC specifies maximum of 30 mW into 16? and 25mW into 32? (Datasheet page 127). If I solve these for power equations and assume it's voltage-output, I get different results for the two loads (692mV into 16? & 900mV into 32?). Why is this? I imagine it might have something to do with the output resistance of the amplifier but I'm not sure. Is there any rule of thumb I could use to determine the maximum power to a 300? load?(WM1811 Datasheet can be found here:http://www.datasheetlib.com/datasheet/1377286/wm1811gecs-r_wolfson-microelectronics.html)EDIT: The forum appears to have replaced all of my omega symbols with ?.

author: Fank1
author_rank: Regular Contributor
timestamp: June 26, 2014, 02:19:10 am
content: It probably has to do with the internal resistance plus current limiting.As it is powered form a 1.8 volt source my best guess would be about 1.6 V peak to peak.
Determining C value - Page 1
Forum section: electronics / beginners

author: stoica adrian
author_rank: Contributor
timestamp: August 07, 2016, 12:48:48 pm
content: Hello, i study the art of electronics + learning the art of electronics.I reach at 2 labs part - capacitor. @ 2L1 they ask to find the value of an R and C value of a low pas filter. I introduce an R=10K and a C=,01uF.Using an osciloscope and function/arbutrary waveform generator i descover how to find the value of an unknown resistor (10K) using an Rtest resistor. Now, i try to find the value of an unknow capacitor ( ,01uF). But i don't know where to start. In the lab course they offer a hint how to descover R value, but not how the descover the C value.Ideeas? Sorry for my english

author: Andy Watson
author_rank: Super Contributor
timestamp: August 07, 2016, 01:32:33 pm
content: I do not have a copy of Learning the art of Electronics - so I will have to guess the method.How did you determine the value of the unknown resistor?Do the same for the capacitor to determine its impedance (reactance) Xc. Then make use of the formula \$X_c = \frac{1}{2 \pi \; f \; c}\$. For best results select \$f\$ to return similar values of \$X_c\$ and Rtest.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 07, 2016, 02:02:44 pm
content: http://www.tek.com/document/application-note/capacitance-and-inductance-measurements-using-oscilloscope-and-function-ge

author: Andy Watson
author_rank: Super Contributor
timestamp: August 07, 2016, 02:05:38 pm
content: I am not sure that I undersatnd your diagram, could you post the description from Learning AoE that you are following.
Determining Error in Voltage and Phase of AD9106 DAC - Page 1
Forum section: electronics / beginners

author: homelykoala
author_rank: Newbie
timestamp: April 02, 2025, 01:51:39 am
content: I'm working with an AD9106 12-bit DAC (https://www.analog.com/media/en/technical-documentation/data-sheets/ad9106.pdf) using its EVAL-board (https://www.analog.com/en/resources/evaluation-hardware-and-software/evaluation-boards-kits/eval-ad9106.html#eb-overview) and have it up and running with an Arduino UNO R3 (schematics attached) to produce 4 sinusoidal signals with independent control of their amplitude and phase over a bandwidth of 9Hz-2Mhz. I'm looking to determine the uncertainty in the amplitude and phase of each channel and was wondering if the following estimates are valid.For amplitude uncertainty, I read that the main contributions are Offset Error, Gain Error, Nonlinearity Errors (DNL and INL) and Quantization error. We correct for offset and gain errors in code, so I consider those negligible. DNL and INL seem to be correlated so I only consider the INL of 0.5LSB as the larger of the two listed in the AD9106 datasheet 3.3V DC specifications (based on the schematics from the eval board). I also read that quantization error takes the form 1/sqrt(12)LSB based on this TI Application Report (https://www.ti.com/lit/an/slaa013/slaa013.pdf). Despite this, the report seems to imply in Figure 7 that quantization error is included in total ADC accuracy but not DAC. I'm not sure why this would be the case though.If quantization error is included, would we estimate the amplitude uncertainty as the root mean square of INL and Quantization?Verr = sqrt((0.5LSB)^2 + LSB/12) = Vfs/1023 * sqrt(0.5^2 + 1/12) ~ 0.26mVWhere Vfs is the full scale voltage (~460mV for Channel 1) and 1023 = 2^{10} - 1 (the dac voltage control is effectively 10 bit).As for phase, we have 16bit control to give worst case error of 0.006deg. I saw in Analog Devices AN-1067 Equation 21 that jitter, j, from the clock source could contribute to the phase error, Perr, through j = Perr/(2*pi*f), where f is the output frequency. The EVAL board seems to be clocked by an AX3DCF1 156.25MHz crystal oscillator what has j = 115fs, so we expect something like Perr = 0.00004deg at 1Mhz so that quantization error dominates.I asked Analog Devices about these, and they mentioned that I don't account for frequency variation as shown in Figures 13-17 of the AD9106 datasheet. We are sticking to the 9Hz-2Mhz frequency range and the AD9106 is suitable for Mhz application so I was thinking our frequency response would be flat enough to ignore.Are there other factors I should consider to calculate these uncertainties? Also, are there any standard tests I should be doing to evaluate the noise in the system.Thanks
Determining maximum/nominal pole current in a servo motor - Page 1
Forum section: electronics / beginners

author: Mr.B
author_rank: Unknown
timestamp: June 16, 2024, 01:55:48 am
content: Hi all,I am looking for some hints on how to determine the pole current for a couple of servo motors scrapped out of a Logitech Rally Camera.They are both two pole servo motors (4 wire).The pan motor is about 3 times the physical size of the tilt motor.The pan motor is 39.2mm X 39.2mm X 24.8mm (1.54in X 1.54in X 0.98in) - Slightly smaller than NEMA 17.The camera was:Logitech Rally CameraUSB 3.0 powered.One pan servo.One tilt servo.Multiple miniature 'servo like' motors in the zoom and focus mechanism.The optional plug pack is rated 5V, 15w. Theoretically the device draws less than this. (i.e. < 3Amps )Google has not been able to reveal any information based on the servo markings:Larger one:STEPPING MOTOR39H023HM-0404-01S/N: 200812090564Smaller one:STEPPING MOTOR36H012HM-0504A-006S/N: 200610030251(I am a little surprised that such seemingly insignificant parts have individual serial numbers.)Coil resistance of the larger servo is 27.28 ohms.Coil resistance of the smaller servo is 16.8 ohms.If the nominal supply voltage is assumed to be 5V...This implies that the larger servo is ~183mA per pole and the smaller one is ~297mA per pole.I must be making an incorrect assumption here, as I would have thought the larger servo would have a higher current requirement, or that this is not the correct method of calculation.They will be driven by a cheap little A4988 driver in my project.I have a little project that I can hopefully use these in.Otherwise I will just buy a couple of NEMA 17 servos and get on with the job.Any assistance on working this out is much appreciated.

author: Mr.B
author_rank: Unknown
timestamp: June 18, 2024, 05:57:39 am
content: No gems of advice from the community?

author: aliarifat794
author_rank: Regular Contributor
timestamp: June 18, 2024, 07:19:11 am
content: Larger motors typically handle higher currents, but if the tilt motor has a lower resistance, it can indeed draw more current for the same voltage. Using an A4988 driver will help you manage this by controlling the current directly.

author: Mr.B
author_rank: Unknown
timestamp: June 18, 2024, 08:36:34 pm
content: The real issue here is determining what current I should set on the A4988 driver.Too little and I will not achieve much torque.Too much and I will damage the servo motor.Goldilocks needs the porridge to be just right...
Determining motor voltage - Page 1
Forum section: electronics / beginners

author: THATguy
author_rank: Regular Contributor
timestamp: April 21, 2017, 04:15:53 am
content: I have two motors from a CD-ROM drive. One has 4 wires, the other 11 wires.Are these motors DC?I can put the drive back together to test if necessary, though I'll need some advice on which wires to test.I wish to make X & Y drive rails for a mini CNC drill. So the first smaller motor can already do this job.The second motor I wish to use to get different rotation degrees. It does not need to be fast, I could easily replace this 11 wire motor with a simple DC fan motor if you think that would be less hassle?These motors do not appear to show any voltage ratings on them.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 21, 2017, 05:29:53 am
content: The motors that move the head in an optical (or floppy) drive are typically small stepper motors. There are hundreds of references how to drive small stepper motors by applying a voltage (typically 5V) to different windings in sequence.The spindle motors of floppy, optical, and hard drives are typically multi-pole "DC-brushless" motors. Again, they are actuated by applying power sequentially to the various windings. There are special chips designed specifically to drive those kinds of multi-pole motors. They typically don't work very well at low speeds. They are optimized for smooth operation at a few hundred RPM.

author: Zero999
author_rank: Super Contributor
timestamp: April 21, 2017, 12:07:14 pm
content: The first one looks like a stepper motor and the second, a brushless motor, as mentioned above. They both need different, driver circuitry and won't work directly of a DC supply.
determining THD for generator - Page 1
Forum section: electronics / beginners

author: littlebill
author_rank: Regular Contributor
timestamp: May 11, 2016, 02:32:47 pm
content: is there any way to figure out the THD value for my generator? or how its calculated?

author: Jeroen3
author_rank: Super Contributor
timestamp: May 11, 2016, 03:58:48 pm
content: You use a meter that can measure harmonic distortion. Such as an Fluke 435.

author: littlebill
author_rank: Regular Contributor
timestamp: May 11, 2016, 04:00:43 pm
content: so a normal oscilloscope can't do it?

author: Jeroen3
author_rank: Super Contributor
timestamp: May 11, 2016, 04:26:31 pm
content: I'd assume such thing is possible using FFT.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 11, 2016, 04:45:47 pm
content: Quote from: littlebill on May 11, 2016, 04:00:43 pmif you know what you are seeing and limitation of the entry level scope... analyzing in FFT domain may give you some clue. for example, usinghttp://www.soasystem.com/download/visadso/a file of pure sine signal in csv format, generated from a simple computer software, not from imperfect real world, is provided in sample directory. you may import the file in (a) raw data and then (b) byte data, with each type of data you may plot the FFT and look at the THD of both. with theoritical perfect sine captured as real data, the THD is 0%. but when downsampled to 8 bit data, the THD is 0.3205%, this is the best a dso can give you, assuming your generator is a perfect sine generator with 0% THD, and the dso has a perfect sampler system, for example sampling period dT(n) = dT(n+x) with x is positive integer, no variable offset in the ADC etc to not screw up the Nyquist sampling requirement... when you have a little bit idea about this, ie your scope limitation, and how it looks like for a perfect sine's FFT downsampled to 8 bit on the screen, then you may take necessary action to compensate or subtraction, when you do a real measurement with your scope and the VisaDSO or any other SW capable of doing large data set of FFT like matlab etc. some other people swore by the averaging function of the scope, but i'm not one of them at this particular application. i may use it, but in conjuction with non-averaged signal, just to check the validity or to get an idea how far i may be off. but then, this is a poorman method, the proper way is to use the dedicated instrumentations.

author: danadak
author_rank: Super Contributor
timestamp: May 12, 2016, 10:49:48 am
content: A couple of useful ap notes -http://www.analog.com/media/en/training-seminars/tutorials/MT-003.pdfhttp://www.tek.com/dl/55W_8815_2.pdfRegards, Dana.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 12, 2016, 11:09:28 am
content: Is the "generator" you want to look at a 3 phase 440V 40 KW diesel at 50Hz?I made a video showing my attempt to use a DSO to make some decent AC line measurements. Part of that was THD.
Determining the charge current of a 6cell li ion Battery Pack - Page 1
Forum section: electronics / beginners

author: 24602
author_rank: Contributor
timestamp: March 17, 2023, 03:33:31 am
content: Hey AllPurchased a 6 cell LI Ion Battery pack 12.5V 6000mah capacity. Tried to get more details from the seller but they couldn't help.Listing states using Samsung 21700 cells. (no exact model specified)The pack has a continuous output of 15AThinking the cells are 3000mah 3x in series then doubled to be parallel.The supplied charger is a generic 1A 12.6V li Ion charger/ PSU. Which is very slow to charge a pack of this size.Typical Li Ion cell charge rates are at 0.5-1C.When in a pack can a suitable charging current be (for this pack) 3-6A?

author: Psi
author_rank: Super Contributor
timestamp: March 17, 2023, 03:55:59 am
content: Hard to say since we don't know the specs of the battery.But 0.5C is probably safe. So 3A.6A might also work but without knowing the spec of the cell it's a bit risky and may cause damage if the cell isn't rated for it.Even cells that are rated for 1C charge are slowly damaged by it and last longer if you charge them slower.Are you sure it's using 2170 cells, 15A discharge seems odd for a 2170 cell and even more odd for 2 in parallel, sounds more like 18650 cells

author: shapirus
author_rank: Super Contributor
timestamp: March 17, 2023, 09:42:02 am
content: Quote from: 24602 on March 17, 2023, 03:33:31 amNormally cells are first parallelled, then these parallelled cells are connected in series. It usually makes no sense to do otherwise.Quote from: 24602 on March 17, 2023, 03:33:31 amThe best way to determine this is to measure the actual capacity of your battery (fully charge, then do a measuring discharge with an electronic load) and you'll know the C. Then, 0.5C for normal charge, 1C if you want quick charge.
Development board for a MP3/Media player project - Page 1
Forum section: electronics / beginners

author: daniel5555
author_rank: Contributor
timestamp: June 18, 2013, 03:42:16 pm
content: Hello guys.I’m a computer science student (not specifically electronics-related), but I have a project which consists in implementing my own firmware for Mp3/media player.I wouldn’t need to touch the electronics part itself, so it’s not circuit-related. I would rather use some board with a bunch of components like a microcontroller, screen, etc, and program it to act like an MP3-player.Ideally this player should be able to navigate and select files from a SD-card, play them, have all the typical controls of an MP3-player (like change sound volume, scrolling, etc) and additionally have some other functions (like displaying JPEG photos). The more functions, the better. Ideally I want it to be as close as possible to the real commercial players. So you can guess that it also should have a good interface, ideally a touch screen interface with icons.This project seems to be pretty big and I’m not sure if it’s feasible to make it all alone (in 3-4 months or so starting from September), but I can reduce the requirements a bit later, since it’s my own project, even though I do it to get a degree from my University.So my question is what board would you recommend for this project? I had experience programming PICs with a small touch screen, but I wouldn’t mind to go to other architecture, particularly ARM.I myself am very interested in this Mikromedia Plus board:http://www.mikroe.com/mikromedia/plus/stm32/, because it looks like it has everything that I may need for my project and it gives me a lot of possibilities, but I don’t know if it’s a good choice for a beginner.I also would appreciate any advice on programming for ARM/your suggested architecture, like what manuals should I read to become familiar with it, what IDEs (preferably free) are the most appropriate for this task, etc.Another thing I need to mention is that I’m not particularly interested in implementing a decoding algorithm. I would rather focus on implementing a way to navigate files using MP3-tags and other functions, while the decoding/playing part would do a specialized circuit.Thank you!!
Device current measurement - Page 1
Forum section: electronics / beginners

author: Pinout1
author_rank: Newbie
timestamp: February 05, 2024, 04:35:23 pm
content: Hello everyone,Has anyone tried to measure current using one of the MCU GPIO with its on/off time measurement? I'm trying to figure out how I can measure the current of the device in this way, distinguishing the separate processes (functions) which are taking place. The problem is, that there are no running processes in the application with a clear sequence. I'm thinking what could be the principle of measurement when processes are not defined in time (interrupts, rtc events and so on...)? I cant use adc also for this research, only power measurement device and toggling some gpios, which works perfectly when the processes used in the software are consistent.Thanks for the answers.

author: bidrohini1
author_rank: Contributor
timestamp: February 05, 2024, 08:17:03 pm
content: If your processes are triggered by interrupts, log the timestamps of these interrupts. This way, you can map GPIO toggling to specific interrupt events.
Device Failing when Unplugged (PoE) - Page 1
Forum section: electronics / beginners

author: jayalt
author_rank: Contributor
timestamp: January 29, 2021, 04:27:42 am
content: Hi all. Looking for some help troubleshooting my PoE (power over ethernet design):My design appears to be working well, with sufficient power and ethernet connection. However, I began noticing occasional failures when I go to power cycle my devices from my PoE switch.I spent a ton of time running different scenarios, and finally narrowed it down to this: my PoE devices are failing when I UNPLUG the ethernet cable from the device. Sure enough, after a few power cycles, I was able to capture this massive current spike I've only seen at time of unplug. See image attached.Question is: why is this happening? Is my cable making weird contact / shorting when I go to unplug it? How do PoE designs prevent this?

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 30, 2021, 10:28:52 pm
content: It will probably be useful to show the diagram.When the PoE voltage is transmitted, it passes through the windings of the balanced transformer. Disconnecting the transformer, which is the inductance, causes an EMF that has reverse polarity and high potential.On which line did you detect a current surge? On the power supply or in the signal?
Device powering from USB type-C - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: March 15, 2025, 01:19:42 pm
content: So, I am planning to build a device that is going to take the input power and data from USB Type-C connector from a laptop.I need some suggestions on a couple of questions.I am planning the device to not take more than 2A overall.I am going to power the device from the USB Type-C connector. USB Type-C Default (Without PD negotiation): 5V @ 1.5A (7.5W) or 5V @ 3A (15W) depending on the host capability So, I don't think power is going to be an issue.Using the same Type-C USB connector, there will be some data that is going to be provided to my device. I was thinking of some 32-bit microcontroller, say SAMD21, but it doesn't support USB3.0Any suggestions on what some low cost microcontroller that will support USB3.0 with OTA?

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 15, 2025, 02:06:18 pm
content: Do you need usb 3.0?USB 3.0 sockets fully support USB 2.0 mode.
Device sheet symbol question - Page 1
Forum section: electronics / beginners

author: magnozo
author_rank: Newbie
timestamp: August 11, 2016, 07:45:42 am
content: Hello folks! I have a problem with using Device Sheet Symbols.When I use these symbols in a new project it works fine, I have 3 instances of a symbol and all of them are created on the Pcb (REF_A, REF_B, etc.).But when I use the same 3 instances on one of my existing projects, I have only one room created on the pcb.

author: magnozo
author_rank: Newbie
timestamp: August 11, 2016, 07:53:31 am
content: And one more thing, the existing project was improted from PCAD, maybe that causing the problem?