hybridfree/eevblog-posts huggingface dataset:
Sourcing tactile domes - Page 1
Forum section: electronics / projects

author: Digibin
author_rank: Regular Contributor
timestamp: May 04, 2015, 07:11:33 pm
content: I'm interested in using tactile domes in my project as front panel user interface buttons. Trouble is I can't seem to find anywhere that I can just buy a load from. A Google search of 'tactile domes' brings up loads of manufacturers websites, but they don't sell directly so I was hoping RS/Farnell/Mouser/Digikey would supply them, but they don't appear to sell them.I'm in the UK - does anyone know where I can buy these from? I've tried eBay, no joy.Anything similar to this really:http://www.clik-domes.com/wp-content/uploads/2013/10/S-Range2.pdf

author: Thor-Arne
author_rank: Unknown
timestamp: May 04, 2015, 07:20:39 pm
content: Something likethis, if you don't mind the long delivery time.

author: CrashO
author_rank: Unknown
timestamp: May 04, 2015, 07:23:29 pm
content: A similar question was askedhereabout a month agoYou could try mailing Snaptron, they pretty much discourage resellers so you could probably buy some from them. But it would depend on the amount. (at for example 50pcs, I would understand them not wanting to sell). Seeing as these things are sold in pretty large quantities.*edit*Fixed the link

author: Digibin
author_rank: Regular Contributor
timestamp: May 04, 2015, 09:01:59 pm
content: Thanks for the link. I did try searching the forums but that thread didn't show up.I may actually just go with theultra low profile switchlinked to in that thread. May be easier in the long run.

author: mariush
author_rank: Super Contributor
timestamp: May 04, 2015, 09:17:33 pm
content: Farnell has a bunch of these, but they're mixed with the more regular button switches .. filter by "switch terminals: solder" and you should find a bunch (oh, and double check the datasheets, pictures sometimes don't match the exact item):http://uk.farnell.com/panasonic-electronic-components/evqplma15/switch-tact-4-9mm-smd-2-6n/dp/2079484http://uk.farnell.com/e-switch/tl3315nf160q/switch-tactile-spst-0-05a-smd/dp/2103642http://uk.farnell.com/alps/skrbage010/switch-1-1n-4-8x4-8mm-low-profile/dp/2056852http://uk.farnell.com/panasonic-electronic-components/evqq2w02w/switch-smd-6-5x6x2-5mm-2-6n/dp/1821256http://uk.farnell.com/alps/skqgaee010/switch-0-98n-5-2x5-2mm-no-actuator/dp/2056842http://uk.farnell.com/multicomp/mcm2a-l/tactile-switch-double-action-smd/dp/1522043

author: aargee
author_rank: Frequent Contributor
timestamp: May 05, 2015, 06:43:05 am
content: Where are you?Make sure the PCB is flashed with a high wearing conductive coating otherwise you'll be replacing/cleaning them every time the weather changes.I can throw some in an envelope for you from my bits and pieces collection if you ultimately can't source any.
Sourcing thermal conductive sheets for transistor heatsinks? - Page 1
Forum section: electronics / projects

author: amaschas
author_rank: Regular Contributor
timestamp: October 02, 2025, 05:04:21 am
content: Hey all, I'm trying to source a replacement for this ripped sheet of material that lines this large heatsink. I'm guessing it's the same stuff that you can get cut down to size for individual transistors. It's very thin, thermally conductive (I assume) and doesn't appear to be adhesive. Does anyone know where I can source this stuff in sheets like this?

author: gamalot
author_rank: Super Contributor
timestamp: October 02, 2025, 05:23:17 am
content: They’re super easy to find on AliExpress.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 02, 2025, 05:29:16 am
content: The one in the picture can be reused, doesn't have to be in one piece. It's role is to be electrically isolator while being a thermal conductor between the transistors and the heatsink.

author: Benta
author_rank: Super Contributor
timestamp: October 02, 2025, 11:29:56 am
content: 3M/Scotch make them:https://eu.mouser.com/ProductDetail/3M-Electronic-Specialty/5519-0.5?qs=B2toaPEvOxGGSU06l%252B3SwQ%3D%3D

author: edpalmer42
author_rank: Super Contributor
timestamp: October 02, 2025, 07:16:03 pm
content: The most common brand name for these things is "Sil Pad". It's available as sheets, strips, pre-cut for various shapes, etc.

author: Smokey
author_rank: Super Contributor
timestamp: October 02, 2025, 09:22:17 pm
content: Digikey:Product Index->Fans, Blowers, Thermal Management->Thermal->Pads, Sheets, Bridgeshttps://www.digikey.com/en/products/filter/thermal/pads-sheets-bridges/218

author: voltsandjolts
author_rank: Unknown
timestamp: October 03, 2025, 07:42:42 am
content: Quote from: RoGeorge on October 02, 2025, 05:29:16 amIf has been torn during disassembly, yes, ok to reuse as long as the tear is not under a device.If the material is disintegrating due to age, then no. New cracks could appear under a device and thus significantly reduce creepage and clearance distance of the electrical isolation.
SP-PW1-10 (Metcal SP200 power supply) schematic and BOM - Page 1
Forum section: electronics / projects

author: t0m
author_rank: Regular Contributor
timestamp: February 26, 2021, 10:38:20 pm
content: I found this schematic floating about on the web, and decided to compare it against the PCB of my recent fleabay purchase.I verified that pin 4 of the UC3823N is not connected to ground, as notedhere.On my PCB, capacitor C5 was omitted and the integrator C3 had a slightly different value.The schematic omitted the EMI filter. It also omitted the green LED that illuminates when the unit is switched on, the anode of which connects to U2 pin 12 via a 330 Ohm resistor.

author: t0m
author_rank: Regular Contributor
timestamp: March 16, 2021, 05:53:39 am
content: I'm pretty sure the big chokes are wound on T106-2 cores.Brian Doreyhas the power FET as IRF840.More picshereandhereandhere.

author: quadtech
author_rank: Regular Contributor
timestamp: March 16, 2021, 06:52:57 am
content: Quote from: t0m on March 16, 2021, 05:53:39 amAnd I thought "Magic Smoke" was copyrighted by a certain Dr Price.

author: t0m
author_rank: Regular Contributor
timestamp: March 16, 2021, 09:17:13 pm
content: I am confused by the top rail being +50V. As I understand it, the transformer is rated 115VAC 36VCT meaning that it outputs 36VAC between the end terminals. After full wave rectification with a bridge diode and smoothing, I would expect a maximum potential of 36VDC minus 2 diode drops.

author: oPossum
author_rank: Super Contributor
timestamp: March 17, 2021, 04:20:43 am
content: 36 volts RMS has a peak of 50.9 volts.

author: oPossum
author_rank: Super Contributor
timestamp: March 17, 2021, 05:38:02 am
content: So you get 50 VDC from 36 VAC.

author: t0m
author_rank: Regular Contributor
timestamp: March 17, 2021, 05:48:46 am
content: Do you though? With a nonzero load?

author: oPossum
author_rank: Super Contributor
timestamp: March 17, 2021, 05:50:21 am
content: With no load it will probably be a bit higher.

author: t0m
author_rank: Regular Contributor
timestamp: March 17, 2021, 06:33:53 am
content: OK thanks, I learned something.

author: mwb928
author_rank: Newbie
timestamp: December 27, 2021, 07:06:57 am
content: Hi,I would like to have the procedure to adjust the "current adjust" and the specified value.Thanks a lot.
SP300 Programmer Reverse engineering - Page 1
Forum section: electronics / projects

author: Palmitoxico
author_rank: Regular Contributor
timestamp: May 29, 2016, 01:57:46 pm
content: So, I've acquired an chinese SP300 programmer in 2013 for programming some classic Atmel 8051 microcontrollers. It worked great for that purpose, but the manufacturer dropped support for this programmer on the last versions of their software, so I've decided to try to reverse engineering the hardware and possibly the software to add some EEPROMs and FLASH memories that I have lay around here on the list of supported devices.I also pretend to write some replacement for their software that runs on Linux/*BSD.This programmer uses and PL2303HX chip (fake) as an Serial to USB interface that connects to an unknown microcontroller (they scratched the numbers as always). The microcontroller uses a 48 pin LQFP package.For while I've mapped these pins of the microcontroller (I'll update this list as I discover more):Code:Pin numberFunction123456RX78TX9101112131415XTAL116XTAL217GND181920212223242526272829303132333435363738394041VCC42434445464748Please let me know if you have a guess for the microcontroller tha this thing uses.I've attached some photos of the programmer.

author: amyk
author_rank: Super Contributor
timestamp: May 29, 2016, 04:14:01 pm
content: STC12C5A60S2

author: Palmitoxico
author_rank: Regular Contributor
timestamp: May 29, 2016, 04:21:47 pm
content: Quote from: amyk on May 29, 2016, 04:14:01 pmOw, I can't thank you enough!I'll update this thread as I progress.
Space Blaster MP - power consumption calculations - Page 1
Forum section: electronics / projects

author: Youkai
author_rank: Regular Contributor
timestamp: April 10, 2023, 01:30:57 am
content: I have the schematic for my project locked down now (I think). Time to start figuring out power consumption. This isn't something I've done before and I'm having trouble getting some of the numbers. Also I don't know what to do with the numbers once I have them. Please review below and provide any assistance you can. Thank you!HS-55 x5:2000mA- 5.5mA idle, 150mA no load, 450mA stall, using 400 x 5 as the valueHS-311:600mA- 7.7mA idle, 180mA no load, 800mA stallDF Player Mini:30mA- 30mA this doesn't seem right based on things I read about this using a lot of powerDotStar x10:600mA- 60mA. Assuming full white of 10 active LED as the average.Speaker: ?? - No idea. 8ohm 1wattXL4015 Buck x2: ?? - No idea. 95% conversion efficiencySwitches: ?? - close enough to 0 that I can round to that?Capacitors: ?? - close enough to 0 that I can round to that?Once I get current draw for the remaining items what do I do with the numbers? Do i just sum them up and multiply by my desired run time then find a batter with that many amp-hours? E.g. if the total was 5000mA, and I wanted it to run for 2 hours I'd get a 10 amp-hour battery?I'm hoping I can find a USB power bank that's small enough, and meets the power needs. If I find one, I should be able to strip one end of a USB cable and use that to power the circuit: correct?

author: orb
author_rank: Regular Contributor
timestamp: December 03, 2023, 01:55:16 pm
content: Quote from: Youkai on April 10, 2023, 01:30:57 amI know, it's an old thread. It looks good in the data sheet, but it is not exactly 95% for each in-out V. For example (XL4015E1 @ 1A load):12V -> 3.3V = ~71%12V -> 5V = ~74,8%20,3V -> 3.3V = ~61%20,3V -> 5V = ~68,2%

author: Youkai
author_rank: Regular Contributor
timestamp: December 03, 2023, 09:02:51 pm
content: Hey thanks for the reply. I ended up using an old USB phone charger that I had in a drawer. The whole thing seemed to work fine off of a 5v USB plug. Yay for that.
Spark Analyzer | IoT-enabled USB-C Adjustable PSU (WiFi + BLE) - Page 1
Forum section: electronics / projects

author: elektroThing
author_rank: Newbie
timestamp: December 11, 2023, 08:00:57 am
content: Hey EEV community,I'm here to introduce an exciting project that I've been working on: the Spark Analyzer. This isn't just another power supply unit; it's an IoT-enabled device that's hopefuly going to change how we interact with USB-C power sources. It's also on CrowdSupplyhttps://www.crowdsupply.com/elektrothing/spark-analyzerWhat's the Spark Analyzer All About?The Spark Analyzer is an ESP32-powered, Internet of Things (IoT) enabled USB Type-C adjustable power supply unit (PSU). This compact, versatile device allows you to power and monitor USB-C devices with ease, making it simple yet useful tool for developers, makers, and electronics hobbyists. You can check out my Instagram for more posts related to the testing - e.g. the App control, driving a 100W load, etc.https://www.instagram.com/elektrothing/Key Features:IoT Connectivity: With its IoT capabilities, the Spark Analyzer can be controlled remotely, offering you unparalleled convenience in managing your power needs.Adjustable Power Supply: It enables precise control over voltage and setting current limits, ensuring that your USB-C devices receive the exact power they require.Ease of Use: Designed with simplicity in mind, the Spark Analyzer is perfect for both beginners and seasoned professionals. With App support for iOS and Android as well as full support with the ESP SDK and Arduino.Excited to hear your thoughts and get any feedback.

author: bookaboo
author_rank: Frequent Contributor
timestamp: December 11, 2023, 08:30:42 am
content: Could be interesting,-Is the code open source?Edit - I just read the link more carefully and can see that it is.- Can it monitor and log current? If so at what resolution, accuracy and sample rate?- ESP-IDF or just arduino?- Can other voltages than 5V, 9V, 15V, and 20V be set?

author: elektroThing
author_rank: Newbie
timestamp: December 11, 2023, 08:40:38 am
content: Yes, it can monitor and log current. At the moment I have tested it to 50mA resolution and a sample rate of around 1kHz.It is compatible with both. Left a little tag-connect in there too.Sorry it also does 12V! There is a typo on my campaign page - will get that fixed.Awesome questions, thanks.

author: bookaboo
author_rank: Frequent Contributor
timestamp: December 11, 2023, 09:58:34 am
content: Could it be set to 3.8V or 3.3V ? Or is that a limitation of Type-C?

author: elektroThing
author_rank: Newbie
timestamp: December 11, 2023, 10:15:55 am
content: That's provided by the switch mode power supply actually. It steps down the USB-C voltage (5-20V) to a stable 3.3V for the MCU's power domain.
Spark Eroder - Page 1
Forum section: electronics / projects

author: icon
author_rank: Regular Contributor
timestamp: November 26, 2012, 09:02:56 pm
content: HiI have an inclination to build a simple spark eroder. I've seen this one:http://www.stockportsme.co.uk/Membersprojects/img/spark_eroder/Spark%20Eroder.pdf. Does anyone have any comments on this design, or information about alternatives?CheersJohn
Spark-Gap Tesla Transformer - Page 1
Forum section: electronics / projects

author: 4beowulf7
author_rank: Newbie
timestamp: July 31, 2015, 07:52:31 am
content: Hi guys!I like to share my design experience on Spark-Gap Tesla Transformer with you. I love Tesla Transformers and Tesla is my favorite scientist of all times!https://tr.scribd.com/doc/272587562/Spark-Gap-Tesla-TransformerGreetings

author: BThunderW
author_rank: Regular Contributor
timestamp: July 31, 2015, 02:38:08 pm
content: Very cool. Reminds me of my first coil I built when I was a kid. I used beer bottle capacitors with a couple 15Kv NSTs. Very messy cause the voltage would occasionally cause the bottles to crack and spill the salt water / oil solution everywhere.I remember reading somewhere that flat primary coil was a lot better solution than the "spring coil" winding. I've always used flat primaries in my builds.
Spark gaps in power supplies - Page 1
Forum section: electronics / projects

author: ivonenand
author_rank: Contributor
timestamp: November 10, 2014, 06:27:48 pm
content: Hi guys!I've seen quite many pictures of power supplies which have spark gaps on PCBs. A few of them have spark gaps placed between the primary and the ground/casing. Some of them have spark gaps placed between the terminals of the input common mode choke. These two locations make sense for me.What I have not yet seen is a power supply with a spark gap placed between the primary and secondary of the main transformer and the primary and secondary side of the feedback optocoupler. Surely these two components have an insulation rating and if exceeded, they will fail. Anyways, I guess my question is, does it make sense to put a spark gap between the primary and secondary side of the transformer? Or is there any specific reason why this is not a good idea?Ivo

author: DanielS
author_rank: Frequent Contributor
timestamp: November 10, 2014, 07:11:17 pm
content: The whole point of ISOLATED output power supplies is to be ISOLATED from mains power. If you put spark gaps from outputs to live mains, that would be a major safety hazard. Unless you want to potentially get sued for wrongful death, don't do that.If you want to prevent your outputs from floating to high voltages, you would either tie your output neutral to ground if you do not need ground/neutral isolation or use a MOV/TVS/GDT/spark-gap from outputs to ground.

author: belasajgo
author_rank: Contributor
timestamp: November 10, 2014, 09:12:16 pm
content: Think about what would happen if you had a spark gap between the primary and the secondary of the mains transformer, and voltage spikes would appear caused by lightning.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 11, 2014, 03:52:37 am
content: The isolation barrier is designed to ride out surges (2.5kV) and shunt ESD (8kV). Shunting is by way of sufficient isolation barrier plus Y1 type capacitors in parallel: the cap stores the ESD charge and keeps the voltage tolerable.A design intended for "minimal capacitance" might require a spark gap to survive ESD, but these are usually medical grade devices with enhanced isolation, to the point where this again is not needed.Tim

author: macboy
author_rank: Super Contributor
timestamp: November 11, 2014, 02:47:27 pm
content: Is the OP perhaps confusing "spark gap" for "isolation slot" ?

author: DanielS
author_rank: Frequent Contributor
timestamp: November 11, 2014, 05:44:37 pm
content: Quote from: macboy on November 11, 2014, 02:47:27 pmThe vast majority of power supplies I have opened have isolation slots under optocouplers so I would be inclined to believe OP really meant spark gap or equivalent device.

author: Marco
author_rank: Super Contributor
timestamp: November 11, 2014, 06:28:09 pm
content: A spark gap is a crowbar device ... so you're essentially putting unimpeded high voltage on the devices/humans on the secondary side, to save a transformer/optocoupler. That's almost never a good trade off.
Sparkfun MiniGen Voltage Offset - Page 1
Forum section: electronics / projects

author: aw_rw1
author_rank: Contributor
timestamp: February 27, 2023, 08:03:44 pm
content: The MiniGen breakouts a AD9837 DDS function generator but uses a VCC/2 offset. I am not sure if the offset is necessary. Has anyone used the MiniGen? Could you bypass the offset?Here is the schematic of the MiniGen from Sparkfun:https://cdn.sparkfun.com/datasheets/BreakoutBoards/MiniGen.pdf

author: mikerj
author_rank: Super Contributor
timestamp: February 27, 2023, 08:56:20 pm
content: It's has no negative supply rail so the offset is required, without the offset half the waveform would be missing. You can remove the offset at the output by connecting a suitable value capacitor in series with your load to block the DC component. The value of the capacitor will depend on the impedance of your load and the lowest frequency you want to operate at, but AC coupling is not very practical for very low frequencies combined with low impedance loads.

author: aw_rw1
author_rank: Contributor
timestamp: February 27, 2023, 09:26:07 pm
content: That makes sense that there is an offset coming out of the AD9837 output. However, there are two voltage dividers R6/R7 and R9/R10. Why are they in the circuit? Are they to increase the offset out of C4?

author: Buriedcode
author_rank: Super Contributor
timestamp: February 28, 2023, 05:25:05 am
content: The AD9837 datasheet (page 3) indicates the output is between 37mV (0.037V) and 645mV (0.645V). In order to filter and amplify this using single supply opamps, it must be biased around VCC/2 to give maximum headroom above and below this point. C4 blocks DC/gets rid of the DC offset, so now the signal is centred on 0V.But the opamps are single supply, so it must be biased around VCC/2, so R6/R7 adds this DC bias back, and R9/R10 keeps the second opamp (as a filter) biased around VCC/2.
Spartan 3AN - based DIY scope - Page 1
Forum section: electronics / projects

author: wolf32d
author_rank: Contributor
timestamp: March 17, 2016, 04:23:55 pm
content: Here's my basic DIY digital oscilloscope. It's based on the (quite old) Spartan 3AN starter kit. I spent the best part of 3 weeks developing this thing for my electronics exam (I'm a physics student).Specs:- mind-blowing 1MHz sampling rate- 14 bit resolution (I'm using the on-board LTC1407A-1 A/D converter)github repo:https://github.com/wolf32d/fpga_scope

author: Kilrah
author_rank: Unknown
timestamp: March 19, 2016, 10:46:39 am
content: Pretty cool, might be good training to try to port that to my spartan-3e board

author: Thomas
author_rank: Regular Contributor
timestamp: March 19, 2016, 12:42:46 pm
content: Nice project.Should be interesting for anyone working on an oscilloscope (been there, not done that).

author: wolf32d
author_rank: Contributor
timestamp: March 19, 2016, 01:46:23 pm
content: Quote from: Kilrah on March 19, 2016, 10:46:39 amIs it this onehttp://www.xilinx.com/products/boards-and-kits/hw-spar3e-sk-us-g.html?If so, it should be straightforward since it has the same analog capture circuit.

author: Kilrah
author_rank: Unknown
timestamp: March 19, 2016, 04:46:30 pm
content: Yep! That's why it's probably a good choice to get back to it. Should work pretty easily so until it does it's for sure me screwing up

author: wolf32d
author_rank: Contributor
timestamp: March 19, 2016, 05:28:58 pm
content: Quote from: Kilrah on March 19, 2016, 04:46:30 pmLet me know if it works! (the gain control for the Linear Technology preamplifier is still a bit faulty)
Spartan 3E Max DDR transfer rate - Page 1
Forum section: electronics / projects

author: cksa
author_rank: Regular Contributor
timestamp: December 04, 2011, 05:03:47 pm
content: Reading the datasheet for the Spartan 3E family, it says DDR can operate up to 166Mhz, with a max data rate transfer of 333Mbps. Does it mean 333Mbps per bit-width of the DDR interface?e.g. if i interface to a 16-bit wide DDR memory chip, and I can operate it at 166Mhz...shouldn't my data rate be 16 * 166 * 2? (5312Mbps)Also, what would be the maximum width DDR interface the Spartan 3E family can support?

author: Simon
author_rank: Unknown
timestamp: December 04, 2011, 05:18:10 pm
content: as far as i know all dimms are 64 bits data bus so 8 bytes x your bus frequency x your DDR factor (x2 for DDR, x4 for DDRII, x8 for DDRIII), to be honest the higher level in DDR you go the less efficient the bus speed is. I've seen DDR at 80-90% and DDR2 at 60-70%, i hate to think of the real speed of DDR3

author: cksa
author_rank: Regular Contributor
timestamp: December 04, 2011, 05:56:44 pm
content: Dimm's may well be 64 bits.But individual ddr chips you get from, say micron, usually are 16-bit wide.

author: Simon
author_rank: Unknown
timestamp: December 04, 2011, 05:57:55 pm
content: oh you mean your talking about individual chips not modules ?

author: cksa
author_rank: Regular Contributor
timestamp: December 04, 2011, 05:58:52 pm
content: yeh, trying to work out what speeds i can get from interfacing individual chips to an FPGA.

author: Simon
author_rank: Unknown
timestamp: December 04, 2011, 05:59:42 pm
content: well same formula should apply but if the chip's bus is 16 bits wide then that is 2 bytes

author: joelby
author_rank: Frequent Contributor
timestamp: December 05, 2011, 01:54:05 am
content: Quote from: cksa on December 04, 2011, 05:03:47 pmYes, that's right.QuoteIf you mean 'DDR memory interface' and use the MIG, the maximum supported width depends on the device - see table 8.23 inUG086.For DDR I/O in general, you can use all I/O pins with DDR registers simultaneously if you want to.
Sparton 5348CC Tube Radio Help - Page 1
Forum section: electronics / projects

author: The Senate
author_rank: Newbie
timestamp: November 22, 2018, 05:27:20 pm
content: Hi, first time EEVblog poster.I recently acquired a Sparton 5348CC tube radio from the 40's. I am looking to "enhance" it with bluetooth, but preserve as much of it as possible, so I'd rather not rip it apart to add an aux input. I'm planning on replacing all the wax caps and resistors. From what I've read, the Mica caps should still be fine so I'll test them and replace them if needed. The radio has an RCA phono input jack, so I was thinking that I could get a bluetooth receiver to RCA output adapter. However, according to the schematics (which I've included) the RCA signal return line is connected to the hot chassis. I assume that this would interfere with the adapter, if not destroy it. Does anyone have any ideas on how I could go about doing this?

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 22, 2018, 07:35:15 pm
content: It's got a proper mains transformer (T4) so the chassis is not hot.
SPDT Analog switch introduction - Page 1
Forum section: electronics / projects

author: VanitarNordic
author_rank: Frequent Contributor
timestamp: May 31, 2018, 07:20:57 pm
content: Hi,I am looking for an easy to find and cheap SPDT analog switch, the same thing like SPST 4066, but SPDT.Operation frequency is low.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 31, 2018, 09:18:58 pm
content: The direct counterpart is 4053: 3 x SPDT. Depending on the supply 74HC4053 might be better performance (lower R_on, faster, but only +-5 V).There are some single channel ones, but these are not so easy to get and may not be cheaper.
S/PDIF Chip - Page 1
Forum section: electronics / projects

author: rolheiser
author_rank: Newbie
timestamp: April 21, 2015, 05:29:05 pm
content: Hi,I am looking for some direction in choosing an S/PDIF to I2S chip. I need a chip that is quite basic, only looking for something that has non-PCM detect functionality and reset/power down. I have seen some from AKM and Wolfson and was wondering if anyone has some experience in using these chips and can suggest one that works well.Thank you

author: dom0
author_rank: Super Contributor
timestamp: April 21, 2015, 05:57:46 pm
content: dir9001

author: bktemp
author_rank: Super Contributor
timestamp: April 21, 2015, 06:33:16 pm
content: CS841xThey can be used stand alone or connected to a microcontroller.

author: linux-works
author_rank: Super Contributor
timestamp: April 22, 2015, 03:15:29 am
content: I've done a lot of spdif and audio stuff.wolfson 8804 and 8805 are nice receiver/transmitter chips. a bit strange in software mode but easy to use in hw based mode. uses a FIFO inside to lower jitter (or, raise it, if you happen to be below the chip's jitter level).the 8416 is high jitter on input, but it has some nice points (select of 4 inputs even in hw mode).AK has very nice chips (I have yet to use them but I have samples waiting to be explored).my current project, in fact, is an spdif switch using the wm8804 (for repeating/shaping) and something else as a front end to it, for input selection (the 'switch' part). output is spdif but there's also i2s if you need that.you can buy a demo 2in 2out wm8804 board from ebay for about $20 and you can try it out easily and cheaply.here's mine decoding an 88.2 sacd audio file:I'm sending wordclock into the freq counter (part of my project is to send WC into the arduino and have it display the samplerate on the selected input. in fact, that part is done and working:button selects input, led display shows the input 'name' and the number on the far right is the freq-counted samplerate, all done on the arduino nano (on breadboard). even has IR remote for display dimming/blanking and input select.no software to the chip, though; its in pure hw mode and is simply just giving me wordclock, plus I'm doing input selection via a temporary hack. its just an early proto, afterallI like the wolfson chips, overall. this one can receive, transmit and give i2s out all at the same time. the output spdif is FIFO'd and so has lower jitter (likely) than the input signal.

author: SteveyG
author_rank: Unknown
timestamp: April 22, 2015, 12:16:45 pm
content: Seconded on the Wolfson chips, I used them in my (ongoing) audio DAC project.

author: linux-works
author_rank: Super Contributor
timestamp: April 23, 2015, 07:25:46 am
content: fwiw, my completed spdif switchsomeday, I'll have better switch 'fabric' but this eval board gets the job done in the meantime.
SPDIF / TOSLINK Output from CSRA64215 - Page 1
Forum section: electronics / projects

author: Ale2.0
author_rank: Contributor
timestamp: August 09, 2020, 09:58:45 am
content: Hello dear communityI am using a CSRA64215 to receive Bluetooth audio and to control the bluetooth-host. Now my Father wants a similar thing but without a DAC and just with an optical output.I have read in the datasheet of the CSRA, it should be able to output the needed datastream. Or so.Thats where I am stuck. I don't really know what I need to input into the optic out. Can I just use a red Led with the connector and output the pcm stream of the CSRA? I sadly just am able to find user grade information about using optical output. If you have information so please feel free to suggest me some links!Thanks for any help and enjoy summer!

author: Bassman59
author_rank: Super Contributor
timestamp: August 09, 2020, 07:10:21 pm
content: The data sheet indicates I2S port outputs. So you need to add an S/PDIF transmitter like TI's DIT4192 or DIT4096, which takes I2S in and outputs AES3.

author: Ale2.0
author_rank: Contributor
timestamp: August 09, 2020, 07:12:00 pm
content: Hey thereYes I have now seen that it's just spdif in and no out!Thank you very much for the chip recommendation, seems like the best option to go for!
SPDT directs minus terminal battery either to charger or the device it powers - Page 1
Forum section: electronics / projects

author: buck converter
author_rank: Regular Contributor
timestamp: July 30, 2017, 10:07:28 pm
content: Is it a good idea?

author: Circlotron
author_rank: Super Contributor
timestamp: July 30, 2017, 10:22:32 pm
content: It is normal practice to put the switch on the positive side. The circuit as drawn will still work okay with the switch in the negative side, but if you have your circuit connect to other equipment and the earths of the two are joined, operating the switch may cause unexpected results when it partially disconnects the earth.

author: buck converter
author_rank: Regular Contributor
timestamp: July 30, 2017, 10:24:46 pm
content: Thank You!
Speaker Inductor direction ? - Page 1
Forum section: electronics / projects

author: picandmix
author_rank: Frequent Contributor
timestamp: May 25, 2018, 11:43:10 am
content: Hi,Recently rebuilt some speaker crossovers, renewing the capacitors and rewiring the rest of the components.There is now a speaker imbalance so will be checking everything out, but wondered if the direction of the two inductors in each speaker are wired would make any audible difference , one is ferrite one in air cored.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 25, 2018, 11:51:55 am
content: For the inductors shown there can be inductive coupling to neighboring parts -especially inductors. As an example if you take 2 of those in series, the inductance could vary from maybe 1.8 time to maybe 3 times to inductance of 1 part.The inductor with ferrite core might show some nonlinear effects too. It depends on the ferrite material used - so a core can be OK but can also be bad.

author: JohnG
author_rank: Frequent Contributor
timestamp: May 25, 2018, 12:07:42 pm
content: The inductors should be mounted such that the winding axes are perpendicular, that the two axes are in different parallel planes separated by 2-3 times the largest inductors maximum dimension. These inductors should also be mounted away from other conductive materials like speaker driver frames or terminal plates, especially if they are steel. Finally, the ferrite core inductor should be far from the driver magnet.John
Speaker magnet direction? - Page 1
Forum section: electronics / projects

author: Roberts_Curiosity
author_rank: Contributor
timestamp: December 10, 2022, 03:47:02 am
content: So, is there some standard for the direction of speaker magnets ?I.E. North facing out of the front of the speaker, or South facing out?I've been digging through datasheets, and can't find any that specify the direction.I promise this is not an audiophool question. There's a serious manufacturing line involved.I can't give details here ... NDA's and all that.Thanks in advance for any thoughts!A few datasheet examples...https://www.digikey.com/en/products/detail/ole-wolff-electronics-inc/OWS-1330TA-8/16735157https://www.digikey.com/en/products/detail/pui-audio-inc/AS09208AR-R/6173655

author: bdunham7
author_rank: Super Contributor
timestamp: December 10, 2022, 04:11:05 am
content: I don't know, but I cannot see any reason to have such a standard. Whichever way the magnet is, you can reverse the speaker's polarity just by how you mark the terminals. The speaker should move outwards when positive voltage is applied to the positive terminal, that is a standard AFAIK.

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: December 10, 2022, 04:31:28 am
content: The polarity is fixed by the magnetizer machine to have the south pole at the back plate.
Speaker & MEMs Microphone design considerations wearable device - Page 1
Forum section: electronics / projects

author: waymond91
author_rank: Regular Contributor
timestamp: January 07, 2022, 07:36:56 pm
content: Hello again!As some may know, I’m laying out a wearable GPS tracker to use while I’m snorkeling/spearfishing/freediving. A feature I’m working on adding in is a simple ‘walkie talkie’ so that dive partners can easily communicate while on the surface (even being 10 meters away from your partner is enough to drown them out - the ocean is loud, your ears are often a little wonky from the diving, and often times people have a hood on).To make matters more complicated, the enclosure has to be totally water tight, so there is no great way for sound to enter and exit the design.I like to think of myself as pretty handy doing embedded DSP stuff, so I though it might be possible to kind just brute force the signal through the wall of enclosure.So far I've selected a ICS-43434 for a microphone (although I'm not particulalrly attached to it, there was just availability for it last time I checked) and I’m using a MAX98357 (a la adafruit) to drive the little speaker. I am in the process of selecting a speaker. Right now I’m just looking at parts from Soberton Inc because digikey found them for me and their data sheets are pretty XDMy main concern is that the speaker will simply be too quiet. My board is getting quite cramped, so I’m hoping to keep the speaker under 20x20 mm (if not 15x15mm) and board mounted.I was wondering if anybody had any thoughts on the matter? Are there particular speaker technologies I should look at? How big a role does mounting play in the quality? Its frustrating looking at a frequency response curve of the speakers, when surely an audio clip from the test data would be better.One specific question I have is if I can meaningful improvements by boosting the low-frequencies in the signal digitally? For example, from what I’ve read the “core frequency” (but also the lower end) of the human voice is centered between 120-200 Hz for adults. However, most of these little speakers really drop off when lower than 1Khz.Would digitally amplifying the low frequencies be damaging to the speaker? Would it make a noticeable difference?Sorry to keep spamming this forum, however I’ve been getting such good feedback its starting to get addicting. I haven’t had these kind of online interactions since I was in university on DIY Drones back in 2012-2013. Now the site is mostly a market place…

author: themadhippy
author_rank: Super Contributor
timestamp: January 07, 2022, 07:48:52 pm
content: How about a bone speaker instead of a normal driver.
Speaker recommendation for use with DFPlayer Module - Page 1
Forum section: electronics / projects

author: Youkai
author_rank: Regular Contributor
timestamp: May 20, 2020, 12:26:11 am
content: I'm working on a project that is going to use a DFPlayer module with Arduino to play some audio clips. I ordered the speakers linked below because they were small and quite cheap. They are functional but the audio quality is bad and I'm sure at least some of that is due to the speakers.Anybody have recommendations of speakers they have used in the past that they would recommend? Something in the neighborhood of 1 - 2 inches in diameter and as thin as is reasonable.https://www.amazon.com/gp/product/B07FMR5JGX/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1
Speccing resistor fault/surge power dissipation for mains in LISN? - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: April 04, 2018, 02:23:34 am
content: So I am building a LISN (more details in RF forum) but the question comes up, of how to rate the power of the resistors used to detune the coil.There is a heavy gauge inductor with 80 miliohms of resistance in front of the inductor that has the parallel resistors, which have a total value of 2000 ohms, the inductor they are parallel with has a resistance of 80 miliohms also (it has solder joints in between its windings).I thought a good idea for a short circuit resistance to be 0.01 ohms,so the short circuit current comes out to be like 1.6kA. This means the resistors in the worst case, will dissipate like 1.8 watts each (4 resistors of 500 ohms).But, in normal operation ,say with the load drawing 30 amps, they will only dissipate 18 miliwatts!, meaning I can easily use 1/4 watt resistors.What kind of resistors power rating should be used in this situation? I figure the LISN will be outfitted with fuses for 20A slow blow, connected to a 20A outlet/breaker. I would not want them to get damaged by the load shorting out... but Do I really need to use like 3 watt resistors in this situation? Maybe I need to add another some miliohms for the wiring resistance in the wall.. this would lower the peak current a bit.Coils/internal wiring will be 2.65mm copper.What do the voltage/current parameters (with duration) look like for a mains short in a typical home outlet? How do you rate a resistor to account for this shit due to the time scales?In this situation the inductor has 4 taps, and the four resistors are between the taps, if it matters.

author: CopperCone
author_rank: Super Contributor
timestamp: April 04, 2018, 06:47:48 pm
content: i am just gonna short it out with a current probe on the shunt resistors and see what happens during this design phase
Special arrangement of Kelvin connections - Page 1
Forum section: electronics / projects

author: Jajaho
author_rank: Contributor
timestamp: January 07, 2019, 06:39:07 pm
content: Hello, I'm Jakob,I found a layout recommendation on Kelvin connections in this datasheet from Isabellenhütte.https://www.isabellenhuette.de/fileadmin/user_upload/VMS.PDFIt can be found on the third page and I am referring to the "Layout 2".In this layout, they propose traces with different lengths attached to the pads at precise positions.Can anyone tell me what is going on, please?Thank you very much in advance.

author: timgiles
author_rank: Regular Contributor
timestamp: January 07, 2019, 07:28:25 pm
content: I assume they are trying to reduce the stress caused during the reflow soldering.
Special Stripboard/perfboard for connectors - Page 1
Forum section: electronics / projects

author: conducteur
author_rank: Regular Contributor
timestamp: November 14, 2014, 06:30:08 pm
content: Simple question, does this exist, perfboard/stripboard where you can mount rj12/rj45/db25 and similar connectors on? (connectors with 2 rows of pins, 0,1" spacing, but the other row shifted 0,05" to left/right?)It's for really simple applications.... To simple to design special pcb's for this. It's for the Loconet model train bus.(ie from RJ12 to screw terminals, from RJ12 to ULN2803 and then to screw terminals, very simple things...)

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 14, 2014, 06:40:59 pm
content: Many more on Google image search for: rj45 breakout board

author: conducteur
author_rank: Regular Contributor
timestamp: November 14, 2014, 06:43:48 pm
content: thanks a lot!

author: German_EE
author_rank: Super Contributor
timestamp: November 14, 2014, 08:31:19 pm
content: I use Proto Advantage, no connection, just a happy customer.http://www.proto-advantage.com/store/The bits you want are athttp://www.proto-advantage.com/store/index.php?cPath=2800

author: conducteur
author_rank: Regular Contributor
timestamp: November 14, 2014, 10:18:23 pm
content: Quote from: German_EE on November 14, 2014, 08:31:19 pmNo RJ12 connector board, that's the most important one... The loconet bus makes is an american standard that uses american telephone cable with 6 wires and rj 12 connectors.
Specialized ebike charging cable identification - Page 1
Forum section: electronics / projects

author: pebcac
author_rank: Contributor
timestamp: April 14, 2022, 06:05:35 am
content: I have a Specialized ebike that I'm interested in tinkering with. Is this a proprietary connector or can I get a compatible one on Digokey?

author: thm_w
author_rank: Super Contributor
timestamp: April 14, 2022, 10:08:56 pm
content: Search for HiGo connectors and you'll find similar looking ones, but nothing exactly like that.

author: pebcac
author_rank: Contributor
timestamp: April 16, 2022, 03:59:30 pm
content: Thanks, I think HiGo is indeed the manufacturer. They do have the same blue locking ring used in one of the bike's internal power cables, but with a different pin configuration.

author: m3vuv
author_rank: Super Contributor
timestamp: April 22, 2022, 07:30:12 pm
content: ive had issues like that,i just retrofit 3 pin xlr types,no reason its just what was im my junk box.
Specialized Power Supply - Ideas for Design - Page 1
Forum section: electronics / projects

author: LoveLaika
author_rank: Frequent Contributor
timestamp: April 29, 2020, 02:26:44 am
content: Hi, first post here. I saw EEVblog's forum, and I wanted to ask for some help. I'm trying to develop a specialized power supply with one output providing 5 volts and another output providing -9.5 V. Each voltage output should be able provide a maximum of 1 amp each, though the load for each output will most likely draw less than that. The input is a 15 volt source, and the output should have 100 mV ripple or less.When I first designed this, I was thinking of using the LM317 and LM337 for simplicity. However, it became very evident that the two modules wouldn't be able to handle the maximum current load, most likely overheating. After some research, I looked into using some buck-regulators to provide the voltages I need, specifically the LM2596. They seem pretty common, so I designed a schematic based around that, shown in the attachment, if I can get it to work.I took the base design and added a current limiting feature to the positive voltage. Using a sense resistor, I use some op-amps to read the current going to my load, and a comparator circuit adjusts the feedback pin of the LM2596, lowering the voltage in order to match the current limit given by a voltage source. I'm trying to do the same to the negative output voltage part, but I don't know where to start. Adding a sense resistor as small as 1 ohm causes the output voltage to not remain consistent.I'm not sure if this is the best design, but it's what I came up with so far. I'm open up to new ideas that would help in improving the design, but so far, this is what seems to work. As a new user, I was wondering if you guys had any suggestions or alternatives that could improve the design?

author: Etesla
author_rank: Regular Contributor
timestamp: April 29, 2020, 02:38:48 am
content: Getting .1mV of ripple at full load with a switching power supply in real life is pretty much impossible without extra filtering on the output, and even then that's a pretty crazy specification. Are you sure you need that little ripple?

author: LoveLaika
author_rank: Frequent Contributor
timestamp: April 29, 2020, 05:32:49 am
content: Quote from: Etesla on April 29, 2020, 02:38:48 amSorry, that was a typo. I meant 100 mV, or 0.1 V. I corrected it on the original post.
specially to David L Jones - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: January 11, 2015, 02:40:39 am
content: Hi sir,I am a big fan of yours since the starting of eevblog. I already posted this before but I need somebody to test it since I don't have any professional equipments except scope and multimeter.My question is whether in commercial instruments the set value is set value is based on the calculated value or feedback loop is used to set the DAC value. Why am I asking this because , in agilent E3631 power supply SINGLE DAC used to set 7 different values with a reference rate of 13ms , if feedback loop is used how it is possible to do refresh in 13ms.Why don't somebody test it please.
Specific 4pin ribbon cable - want pin pitch, need eagle part or breakpout board. - Page 1
Forum section: electronics / projects

author: makerimages
author_rank: Regular Contributor
timestamp: January 28, 2016, 06:04:26 pm
content: Hey, A really specific Laptop ribbon cable here..Code:hamburg w e235863 awm 20798 80c 60v vw 1ribbon cable, 4 pin. I'd like to know what it's pin pitch is and what markings on hamburg cables matter, and if you could point me to an Eagle part for the smd connector, or a ready-made breakout board to sth like 2.54 mm pitch, would then that would be cool too.

author: ajb
author_rank: Super Contributor
timestamp: January 28, 2016, 06:32:52 pm
content: "AWM 20798" is aUL "appliance wiring material" classification"80c" is the temperature rating"60v" is the voltage ratingThat leaves E235683, which if you look at Hamburg'swebsiteand squint at the blurry pictures, appears on different pitches of cable. It might be a material marking or refer to another standard, I don't know.So none of that helps you identify the cable's physical paramters, which means you're left to measure the dimensions yourself.Any particular reason you're trying to use this specific cable as opposed to selecting a new one?

author: makerimages
author_rank: Regular Contributor
timestamp: January 28, 2016, 06:35:43 pm
content: Yes I do have a specific reason, the other end of the cable goes to a sensor I want to try interfacing to.. HP's 3uat5fb0010 to be percise. Bloody Hamburg...
Solved, obsolete. - Page 1
Forum section: electronics / projects

author: evb149
author_rank: Regular Contributor
timestamp: April 21, 2016, 05:28:20 am
content: Solved, obsolete.

author: zlymex
author_rank: Frequent Contributor
timestamp: April 21, 2016, 06:30:18 am
content: I tore down this 5 inch hard drive in the similar hope but ended up in despair. The spinning motor is a dedicated one and the voice coil is not useful to me. There might be an encoder inside the motor but I cannot open it except to destroy it. Apart from these, I don't find other electro-mechanical parts. I had another 3.5 inch yet to be tear down.

author: albert22
author_rank: Regular Contributor
timestamp: April 21, 2016, 02:09:33 pm
content: I am pretty sure that getting specs for those electromechanical parts and motors would not be possible.You will have to experiment, perhaps burning one or two. Also in some units, specially old CD/DVD drives, you can identify the bldc motor driver IC and get its datasheetThere are several projects on the web to drive HD motors. Here is one:http://theamateurprogrammer.blogspot.com.ar/2014/02/revitalizing-old-hard-drive-motors.html