hybridfree/eevblog-posts huggingface dataset:
Finding a part help - Page 1
Forum section: electronics / beginners

author: pinkystu
author_rank: Newbie
timestamp: October 14, 2025, 02:38:15 pm
content: Hi First timer posting,I have a small pcb that controls the osd on my monitor and the thumbwheel part has broken off, ive been struggling to find what the part is called to be able to order another.So far i have tried searching with the terms smd thumbwheel jog wheel dial push button 4 pin in various combinations i did find a few pages but when i click on them they dont exist such as this one on amazonhttps://www.amazon.com/1000Pcs-Tripod-Thumbwheel-Toggle-Switch/dp/B0BRG19MB4Ive also tried reverse image searching and i have been unable to find anythingIve included a pic of the switch.The wheel controls 3 inputs up down and enter .Cheers

author: jpanhalt
author_rank: Super Contributor
timestamp: October 14, 2025, 04:14:28 pm
content: Search on SP3T thumbwheel switch. Here's something similar from DigiKey, but it's a Hall switch.https://www.digikey.com/en/products/detail/alps-alpine/SLLB510100/19529346?gclsrc=aw.ds&gad_source=1&gad_campaignid=20243136172&gbraid=0AAAAADrbLliLMAsVuGJ24ENkQ3XZk6-pG&gclid=EAIaIQobChMIscmE84mkkAMVdI4iBR2MbDfuEAQYAiABEgJtrvD_BwE

author: gamalot
author_rank: Super Contributor
timestamp: October 14, 2025, 04:19:53 pm
content: Something like this?https://tech.alpsalpine.com/e/products/detail/SLLB510100/

author: pinkystu
author_rank: Newbie
timestamp: October 14, 2025, 04:51:51 pm
content: Hi Thanks for the replies,I think youve found it gamalot it seems the term is "Lever and Push Operation Type" if anyone else is trying to find one of these, now just to try and find someone who sells them in small quantities or bodge up a few buttons on a perf board >(Cheers

author: gamalot
author_rank: Super Contributor
timestamp: October 14, 2025, 06:26:20 pm
content: Quote from: pinkystu on October 14, 2025, 04:51:51 pmDo you know LCSC:https://www.lcsc.com/product-detail/C125039.html
Finding a replacement for an outdated obsolete component - Page 1
Forum section: electronics / beginners

author: miker7940
author_rank: Contributor
timestamp: April 01, 2016, 12:44:26 pm
content: Hi everyoneWondering what people do to replace an obsolete component from old schematicsthe component in question is a AM29F016D / AM29F032D FLASH 16/32 Mbit SMD SO44If anyone knows a more up to date version of this component, please say

author: daqq
author_rank: Super Contributor
timestamp: April 01, 2016, 12:51:39 pm
content: The SO44 package is a problem, otherwise it should be a generic 29F016/032, such ashttp://sk.farnell.com/micron/m29w320dt70n6e/flash-top-block-32mb-smd-29w320/dp/1099698?ost=29f032&selectedCategoryId=&isexcsku=false&categoryName=V%C5%A1etky+kateg%C3%B3rie&categoryNameResp=V%25C5%25A1etky%2Bkateg%25C3%25B3rie&rpsku=M29F032D70N6E.

author: miker7940
author_rank: Contributor
timestamp: April 01, 2016, 12:54:27 pm
content: Quote from: daqq on April 01, 2016, 12:51:39 pmI can change the package - just as long as they have the same pins (different places is fine though) Thanks for the link. I'll take a look now,Okay, I have had a look and as I expected they have many different pins. And the schematic uses almost all of them on the existing chip.If you've got any suggestions I would be happy to hear them:)

author: daqq
author_rank: Super Contributor
timestamp: April 01, 2016, 06:34:40 pm
content: Also, be wary of the voltage levels. The part I linked is for 3.3V usage.

author: miker7940
author_rank: Contributor
timestamp: April 02, 2016, 12:41:42 am
content: Quote from: edavid on April 01, 2016, 04:09:59 pmI need about 100 of them. And they really aren't very common parts...

author: dacman
author_rank: Frequent Contributor
timestamp: April 02, 2016, 01:00:18 am
content: Although you're (apparently) not in the US, I'd suggest an obsolete parts source, such as 4starelectronics.com or americanmicrosemi.com. Just look for an obsolete semiconductor distributor or an obsolete electronic parts distributor.
Finding an off-the-shelf NFC module with FCC/IC/whatever approval - Page 1
Forum section: electronics / beginners

author: AndrewM
author_rank: Contributor
timestamp: January 20, 2021, 04:16:30 am
content: Hi,I'm building a thing that needs an NFC reader. It's easy enough to find NFC modules for $5 or whatever on aliexpress, but there's no way those will come with FCC paperwork.About the only one I can find from a reputable seller ishttps://www.adafruit.com/product/789which is much too large for how I want to use it.Does anyone here have suggestions or experience with how I could find an off-the-shelf NFC reader module that has already gone through the modular approval process? It's fairly low volume device, I'd probably be buying 200 of them.My other option is designing this thing from scratch, and going through the certification process with it, which I can do if I have to, but I'd rather avoid.

author: SVFeingold
author_rank: Frequent Contributor
timestamp: January 20, 2021, 05:32:21 am
content: Here are a fewfrom Digikey.And afew more.Slim pickings. Considering the size of NFC antennas compared to 2.4GHz protocols that can use chip antennas, I'm guessing that you're generally expected to create your own antenna layout and just use an off the shelf controller instead of relying on a pre-made module which may not be the form factor desired.Found theseready-made moduleson DigiKey. Not cheap but still cheaper than FCC certification.I don't think you need FCC certification if it's a "passive" device that only responds to an active NFC transmitter. But you did say "reader" so I'm assuming that's not the case.

author: AndrewM
author_rank: Contributor
timestamp: January 20, 2021, 10:40:23 pm
content: Yes, it's not a passive device, it reads passive NFC tags.Thanks for the help. I searched digikey earlier and didn't find those modules.I can find plenty of documentation and examples and application notes on how to make your own antenna layout and such (eg:NXP AN1445andNXP AN11535). It's more about avoiding the cost of doing FCC certifcation when I only need ~200 or so units (well, not just FCC, other countries too, it also needs to be able to be used in Canada and much of Europe).200 ofthese thingslooks like it will cost me $5400 USD, which probably ends up cheaper than doing it myself considering FCC costs + my time cost + the cost of whatever I end up designing.Edit: Oh nevermind. I read the datasheet for that thing, and it acts as an NFC tag, not an NFC reader. That doesn't help me at all.
Finding correct volume Potentiometer - Page 1
Forum section: electronics / beginners

author: SquareOne
author_rank: Newbie
timestamp: December 28, 2020, 07:04:40 pm
content: HelloComplete beginner here, that can just about do basic soldering of replacing like for like parts.I am trying to find a B50k Potentiometer that will work in a volume control for an old Creative speaker system.I can't see any markings on it apart from the B50kDone a few measurements on the pins and found the bottom 3 to be variable as it turns.Can't find anything that looks remotely like this, any tips to find something that will work?Cheers

author: TimFox
author_rank: Super Contributor
timestamp: December 28, 2020, 07:10:38 pm
content: The 3 closely spaced pins are the “normal” ones: CW, wiper, and CCW. The other ones connect to the case, for shielding and mechanical support. You could use a “normal” pot with pins to match the three holes, and solder wires from the metal case to the other holes. You probably want log/audio taper unit, resistance 50 k.

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2020, 07:25:55 pm
content: B50K is almost certainly alinearpot. My hunch, given that it's not a stereo pot, is that it's not used to attenuate the signal, but to control a voltage-controlled amplifier.

author: Benta
author_rank: Super Contributor
timestamp: December 28, 2020, 07:28:22 pm
content: Actually, it seems that the "B" would imply linear taper.https://eepower.com/resistor-guide/resistor-types/potentiometer-taper/#I would also have expected a log taper for this application.EDIT: tooki beat me to it. His explanation sounds probable.

author: floobydust
author_rank: Super Contributor
timestamp: December 28, 2020, 07:38:04 pm
content: The middle (wiper) solder joint looks fractured, first try resolder it and use a pot cleaner/lube with PPE if it is noisy, crackly.Common problems are bad solder joints at connectors and mechanical (controls) in Logitech and Creative etc. speaker systems.That potentiometer is not common - it has an on/off switch and right-angle PCB leads. The 50k linear taper is common though. You can find them for sale on Aliexpress.
Finding DC shorts - Page 1
Forum section: electronics / beginners

author: darinsquared
author_rank: Contributor
timestamp: November 19, 2016, 09:27:45 pm
content: I read a post/article on diagnosing short circuits. I thought it might have been in this forum just recently (this week) but I cannot find the post.I am trying to find a short in a long wire run so a conductivity test will not work. One method was using a infrared thermometer or camera. I have access to a thermometer but I do not know how precise it is but I do not have a camera. I thought there was another method but I cannot recall the methodology. Any help would be appreciated. I do not know if this matters but there are multiple wires in a plastic loom. I assume the most likely spot will me a "joint" or where the wires bend.

author: darinsquared
author_rank: Contributor
timestamp: November 20, 2016, 01:27:46 pm
content: Thanks for the reply. I do not have the equipment you mention, I am just a hobbyist interested in electronics. the wiring issue is on large farm equipment. Your second method may work however the wiring harness with the short is in a group of about 10 wires so there would be a lot of trial and error with that amount of combinations.

author: 3roomlab
author_rank: Frequent Contributor
timestamp: November 20, 2016, 01:39:33 pm
content: Quote from: darinsquared on November 20, 2016, 01:27:46 pmwhat test gear do you have or can have access to? DMM ? a neon lamp test stick? cable tracers?

author: Fank1
author_rank: Regular Contributor
timestamp: November 20, 2016, 02:45:46 pm
content: Put a resistor in line at the source, battery, to limit the current to an amp or two and then follow the wire using a compass.The deflection will change when you pass the short.

author: German_EE
author_rank: Super Contributor
timestamp: November 20, 2016, 07:23:50 pm
content: Put a resistor in line at the source, battery, to limit the current to an amp or two and then follow the wire using a compass.The deflection will change when you pass the short.Somebody give this guy a prize, that's the most ingenious solution I have ever heard.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 20, 2016, 07:38:17 pm
content: Connect a low - impedance audible AC source ( e.g. audio amp speaker output) across the end of the cable.This will create a current loop from the end of the cable to the short.Then use a small handheld coil and audio amp to follow along the cable until the tome disappears, which will be near the short
Finding equivalent 4066 IC - Page 1
Forum section: electronics / beginners

author: Dr_Neoo
author_rank: Contributor
timestamp: January 09, 2016, 03:55:23 pm
content: Hello,I'm currently attempting to build the Bus Pirate v3.8 and have run into a part sourcing issue. The partslist (found at the bottom of this pagehttp://dangerousprototypes.com/docs/Bus_Pirate_v3.8) calls for the TC74HC4066AFTELM in a TSSOP14-package (link to datasheet:http://www.mouser.com/ds/2/408/DST_TC74HC4066AP-TDE_EN_365-479492.pdf) but it's not available for purchase from Mouser were I'll be sourcing the rest of my components. After a bit of searching i found the CD74HC4066PWR (link to datasheethttp://www.mouser.com/ds/2/405/cd74hc4066-534313.pdf) which seems to have the same pinout and package. Can anyone confirm if this chip is compatible, point me to one that is or show how to check this in the datasheet.Thanks in advance!

author: lapm
author_rank: Frequent Contributor
timestamp: January 09, 2016, 10:27:04 pm
content: Mouser has tons of tssop 14 pckaged 74hc4066... Are you sure you need exactly this type mentioned?

author: Kleinstein
author_rank: Super Contributor
timestamp: January 09, 2016, 10:35:55 pm
content: Usually the 74HC4066 are not really different from different manufacturers. At least the differences are usually within the tolerances of the specs. Especially if not used at exteme conditions (near maxium temperature or supply voltage) an excange should be ok.

author: Dr_Neoo
author_rank: Contributor
timestamp: January 10, 2016, 10:36:33 am
content: Quote from: Kleinstein on January 09, 2016, 10:35:55 pmThanks for the information, as they are quite cheap I'll try and order a few different ones and it should hopefully work

author: Ian.M
author_rank: Super Contributor
timestamp: January 10, 2016, 11:23:52 am
content: 74 series logic and 4000 series CMOS are generally regarded as genericly substitutable. If your design needs a specific manufacturer's chip that should be indicated on the schematic and BOM, with a note not to substitute.I assume you haven't found such a note in the Bus Pirate documentation so you shouldn't have any problems.

author: Zero999
author_rank: Super Contributor
timestamp: January 10, 2016, 11:28:21 am
content: I notice that the usual 74HC series is rated to a maximum Vdd of 6V, yet the 74HC4066 is rated to 10V.Does anyone know of any other 74HC devices which are rated to 10V? It would be good to have a faster substitute for the old CD4000 series which can work at higher voltages than 6V.

author: Ian.M
author_rank: Super Contributor
timestamp: January 10, 2016, 12:36:07 pm
content: That's specific to it being an analog switch. Finding high voltage tolerant logic is difficult.e.g. the 7407 Hex buffer with open collector outputs, although a 5V device had a Vce breakdown voltage of 30V so could easily be used as a level shifter to control 12V signals. Naively one might suppose that the CMOS functional equivalent would have similar ratings. However the 74HC07, although open drain has upper protection diodes to Vdd on its outputs so cannot be used with an output voltage greater than its supply.
Finding Equivalent P-Ch - Page 1
Forum section: electronics / beginners

author: SG-1
author_rank: Regular Contributor
timestamp: January 05, 2019, 06:00:30 am
content: How does one go about finding the evil twin, I mean the P-Channel equivalent of this NTE457 (JFET).I have looked at the NTE456 & NTE458, both are N-Ch.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 05, 2019, 07:12:26 am
content: Easy! There's about half a dozen P-ch JFETs still in production; just sort through their datasheets and pick the closest one.Don't get your hopes up......Oh actually it's more like three, which in typical JFET fashion, come in three-ish flavors each (neighboring part numbers, sorted by Idss bins), and second-sourced by a couple manufacturers each.https://www.digikey.com/short/p7t4h0Tim

author: David Hess
author_rank: Super Contributor
timestamp: January 05, 2019, 02:51:46 pm
content: Calogic has some p-channel JFETs also if you can figure out where to buy them.The selection of p-channel JFETs is so small that checking them all will not be difficult.

author: Jwillis
author_rank: Super Contributor
timestamp: January 07, 2019, 04:07:13 am
content: Think these P-channels are pretty closehttps://www.nxp.com/docs/en/data-sheet/J174_175_176_177_CNV.pdf
Finding JFET output admittance from datasheet - Page 1
Forum section: electronics / beginners

author: aneevuser
author_rank: Frequent Contributor
timestamp: January 22, 2020, 03:51:32 pm
content: I want to find \$r_{ds}/y_{os}\$ for a JFET (specifically a J105) but it's not quoted in the datasheet (not in this one at least:http://www.farnell.com/datasheets/2304100.pdf?_ga=2.16164336.77463200.1579706202-1922662769.1578909818).OTOH, the datasheet does provide a graph of \$I_D\$ vs \$V_{DS}\$ from which I can estimate it. Is this a sensible way to get the value, or am I missing a simpler/more accurate approach?

author: rfeecs
author_rank: Frequent Contributor
timestamp: January 22, 2020, 07:27:47 pm
content: Maybe look at figure 7 (Output conductance vs Drain Current)?Alternately search for J105 SPICE model. Output conductance can be calculated at a specific operating point. Or you can simulate it with SPICE.

author: aneevuser
author_rank: Frequent Contributor
timestamp: January 22, 2020, 10:10:41 pm
content: Quote from: rfeecs on January 22, 2020, 07:27:47 pmRight, thanks. I hadn't noticed that. Unpleasantly logarithmic (and small) though, so may be tricky to get an accurate value from it.
Finding LRC circuit values when impedance and frequecy is given - Page 1
Forum section: electronics / beginners

author: sean87
author_rank: Regular Contributor
timestamp: April 18, 2013, 12:50:45 pm
content: Hi all,I wonder if you can help me with this question:QuoteFirst, I think that the given impedances are when the frequency is 2000 rad/s , so I tried to find their values when the frequency is 2000 rad/s. Is the approach correct?Then I remember the formula for finding the critical frequency was as how I wrote it in part 2 of answer. Any ideas if this is correct?Also, I have no idea how to find the current across L at resonance. What I remember is that in resonance the impedance of C and L are canceling eachother so the given voltage should be the voltage same across the resistor. Can you check please?

author: w2aew
author_rank: Super Contributor
timestamp: April 18, 2013, 01:26:53 pm
content: Check your math for the capacitor value calculation...

author: sean87
author_rank: Regular Contributor
timestamp: April 18, 2013, 01:46:54 pm
content: OK, I missed the 8 in the denominator...the capacitance should be 62.5 uFMy question is, am I even doing the right thing that the question is asking for?What about current through inductor at resonance? Is it the same current that goes trough the resistor? how to calculate that?

author: kxenos
author_rank: Frequent Contributor
timestamp: April 18, 2013, 06:19:44 pm
content: What is the type to calculate the resonant freq. of a series RLC???

author: w2aew
author_rank: Super Contributor
timestamp: April 18, 2013, 11:14:33 pm
content: Your approach is sound. Calculate the values of L and C with the info given. Use that to calculate resonant frequency. It is a series circuit, so the current is identical through each of the components.
Finding out what connector this is and its pinout - Page 1
Forum section: electronics / beginners

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: October 16, 2013, 04:21:53 am
content: Hello has anyone seen this connector before?This has has come from an old comercial touchscreen vga screen and i am unsure of its pinout.I mostly need the pinout for the greeny connector with the pins on the top row as i have figured out that the bottom is a usb connector and im guessing the top is. Power connector but it is all built into one.Does anyone know what this connector is and what should be connected where?

author: Lifeboat_Jim
author_rank: Contributor
timestamp: October 16, 2013, 10:49:51 am
content: Yep, your right in your thoughts. It's called a 'PoweredUSB' (we're talking about the one on the left, coloured green).Fairly rare for consumer kit, although some laptops (such as Dell Mobile Precision Workstations) had them (until a few years ago at least).I understand the power (top part) can be 5, 12 or 24V, the bottom part ought to be standard USB 1.x or 2.x. PoweredUSB ports can accept a standard USB connector, you just plug it into the bottom (data) portion of the socket. There ought to be no issue with you providing the power separately to the device if you wish and using standard USB cables for the data.Can't help on the right hand plug though.

author: Lifeboat_Jim
author_rank: Contributor
timestamp: October 16, 2013, 10:55:48 am
content: There is more info onwikiabout this.As your PoweredUSB is coloured blue/green that indicates it's a 12V, possibly delivering as much as 72W (compared to standard USB which is 2.5 to 5W or so).

author: amyk
author_rank: Super Contributor
timestamp: October 16, 2013, 11:17:40 am
content: The right one looks like a molded case for a 0.1" header plug.

author: Lifeboat_Jim
author_rank: Contributor
timestamp: October 16, 2013, 11:48:22 am
content: Quote from: amyk on October 16, 2013, 11:17:40 amI thought that too but thought to keep stum. Put a micrometer on it and check if it's pitch is 2.54mm

author: The Adjuster
author_rank: Newbie
timestamp: October 17, 2013, 02:32:53 am
content: We use a ton of these cables at work. What's the manufacturer's class/model number of the LCD? Do you know what it was hooked up to?I'll see if I can find the pin out.

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 17, 2013, 04:21:33 am
content: Open up the LCD and see if you can see where the power side of the plug is going, see if you can see what regulators it is going through and what caps are across the input to give you an approxiomate input voltage, then check continuity with appropriate pins.
Finding replacement transistors - Page 1
Forum section: electronics / beginners

author: fjalvingh
author_rank: Contributor
timestamp: May 14, 2022, 08:55:34 pm
content: Hi all,I am trying to repair a HP 8656B which has trouble on the low frequencies - the low frequency loop is unlocked. I found at least one problem: one transistor in the PLL phase detection circuitry has blown. This is a 2N4209 which seems to be hard to get - so I need to find a replacement... To test I just replaced it (and its brother which form a pair in the schematic) by a 2n3906, and this does solve the problem: the pll locks and I can again select proper frequencies.But that 2n3906 is way slower than the original, so I would like a replacement that is a bit more close to its specs. The transistor seems to be used mostly as a fast switching transistor.And that brings me to the real question.. How to find such a replacement? I did the usual Google dances and looked at Mouser, but I do not seem to be able to select the things I would like (this 2n4209 has 10..15ns turn on and rise time, and that is way less than the 2n3906)..Are there other online resources that I can use to find something like this?Thanks for your help!Regards,Frits

author: bdunham7
author_rank: Super Contributor
timestamp: May 14, 2022, 09:06:42 pm
content: If it works at all with 2N3906 it should be fine with the purported replacement from Central Semi, the CM4209....if you can find it. Don't be too proud to scrounge a few units off of eBay, I see numerous sellers with 2N4209s for not too much money.

author: tepalia02
author_rank: Regular Contributor
timestamp: May 16, 2022, 10:50:37 am
content: This one seems to be close :https://www.ebay.com/itm/255028370686

author: fjalvingh
author_rank: Contributor
timestamp: May 16, 2022, 02:17:41 pm
content: Thank you both for your answers, but there is another thing I would like to know: how to find a replacement type, i.e. another transistor having fast on/off time. Is there any tooling for that? How do you select a component type by the specs you require?

author: bdunham7
author_rank: Super Contributor
timestamp: May 16, 2022, 02:45:57 pm
content: Quote from: fjalvingh on May 16, 2022, 02:17:41 pmThere are such tools, but they aren't magic. Figuring out what your requirements are and then doing a parametric search in Mouser or DigiKey is probably a better use of your time. Or just asking here. But here are two 'cross-reference' tools you can look at.https://www.onsemi.com/products/product-services/competitor-cross-referencehttps://alltransistors.com/crsearch.php

author: kripton2035
author_rank: Super Contributor
timestamp: May 16, 2022, 03:28:53 pm
content: ↓ Type Code Mat Struct Pc Vcb Vce Veb Ic Tj Ft Cc Hfe Caps2N4209 Si PNP 0.3 15 15 4 0.05 200 850 3 50 TO18BC291A Si PNP 0.36 45 45 6 0.2 200 100 TO18BC291B Si PNP 0.36 45 45 6 0.2 200 150 TO18BC292A Si PNP 0.36 45 45 6 0.2 200 100 TO18BC292B Si PNP 0.36 45 45 6 0.2 200 150 TO18MM4209A Si PNP 0.36 15 15 4 0.2 200 850 3 50 TO18NTE106 Si PNP 0.36 15 15 4.5 0.2 200 850 2 50 TO18
finding schematic diagram for identify parts - Page 1
Forum section: electronics / beginners

author: electricenthusiast
author_rank: Contributor
timestamp: February 10, 2023, 10:32:12 am
content: I got an old lvds lcd display from old monitor. But the components in the display tcon board were fried up due to thunder. I want to remove them all to take the picture of the board with missing partsCould someone find the schematic diagram? So that i can reuse the old display. The Model number is on the pcb photo

author: Haenk
author_rank: Super Contributor
timestamp: February 10, 2023, 12:03:09 pm
content: Check ebay or Aliexpress with the PCB part#. I guess it's not too expensive.However - are you sure the damage is limited to the TCON, I think that's unlikely...

author: electricenthusiast
author_rank: Contributor
timestamp: February 10, 2023, 12:51:33 pm
content: no, i need the name/part no of the ics and caps which are burned out from the pcb and i think its better to buy the entire display other than a tcon becaue its not available
Finding Standalone DACs and ADCs - Page 1
Forum section: electronics / beginners

author: homelykoala
author_rank: Newbie
timestamp: April 11, 2025, 09:46:30 am
content: I'm looking to build a general purpose DAC-ADC box that can read in DC signals up to +/- 10V with at least 16bit resolution and also output DC signals in the same range with the possibility of being used for control loops in the future (sorry for the vague requirements, the project is pretty open-ended). Something similar to this build from openDACshttp://opendacs.com/dac-adc-homepage/dac-adc-illustrated-assembly-instructions/would be ideal.I think I am looking for "standalone" ADCs and DACs meant to be controlled by generic mcus so that I can quickly prototype a build. The openDACs build uses the AD7734 and AD5764 eval boards from Analog Devices and it looks like there's some hardware configuration that has to be done in the assembly. I'm hoping I could avoid that kind of tinkering if I choose different parts.I do want low noise performance so I don't want to rely on the internal D/A converters on the microcontroller itself. I think eval boards from analog devices with an Arduino form factor would be easy to work with like the AD4130 ADC, which has the same core as the AD7124 but with smaller ODR. I also came across these third party mikroe boards, like the ADC 6-clickhttps://www.mikroe.com/adc-6-clickwhich uses an AD7124 under the hood but seems a lot easier to interface with. I couldn't find a good DAC in their product line with a similar bit depth though.Looking around analog devices again, I came across this brochure for rapid prototypinghttps://www.analog.com/media/en/news-marketing-collateral/solutions-bulletins-brochures/solutions-for-rapid-prototyping.pdfwhich mentions Arduino compatible boards like the ultra low noise 20 bit MAX5719BOB DAC and the 24 bit 1.9kSPS MAX11410BOB ADC. These seem like good options except the sampling rate on the ADC seems a little low for control applications, but maybe that's ok since we're woring with DC signals.The AD7124 can sample up to 19.2kSPS, so right now I'm leaning towards the mikroe ADC 6 click ADC + MAX5719BOB DAC + Arduino Due.Are there other places I should look at to find standalone DACs and ADCs and are there any glaring problems in this build that I haven't caught?Thanks

author: RoGeorge
author_rank: Super Contributor
timestamp: April 11, 2025, 11:05:04 am
content: If you need only one DAQ for personal use, no longer than a couple of days ago spotted a myDAQ for sale:https://www.eevblog.com/forum/buysellwanted/fs-(eu)-ni-mydaq/
Finding the (Q) points for a BJT????? - Page 1
Forum section: electronics / beginners

author: shanecy
author_rank: Contributor
timestamp: August 06, 2013, 12:21:28 am
content: The question gives the following schematic and says to find the Q point for the Voltage(Collector to Emitter) and the Q point for the Collector Current. It gives beta as 50.I'm using two standard equations from my book to find the two Q points. I followed step by step instructions from my book and I'm being told I'm wrong. The person doesn't support their answer with any work but only says that I cannot use Beta (B) or the two equations from my book "see below" to find the Q points. However, wether i'm finding the Q point or not the two equations are the same just with the subscript Q added.Could someone work this and perhaps tell me if I'm wrong and what I am not taking into consideration. The schematic below is all that is given with B being 50. The 2N3904 was just added in by my simulator but the actual problem just says it's an NPN BJT transistor.FYI my work/answers is in the first attachment with the two equations the book is using.I'm also attaching in the last attachment additional equations I used in my strategy for solving this problem.Also the voltage from base to emitter is assumed to be .7V.

author: fmaimon
author_rank: Unknown
timestamp: August 06, 2013, 02:02:02 am
content: First consider Ib negligible. So Vb = 20 * 10 / (10 + 68) = 2.564VVbe = Vb - Ve = 0.7V, so Ve = 2.564 - 0.7 = 1.864VThen we get Ie = Ve / Re = 1.864 / 1.1 = 1.695 mAIe ~= Ic, so Vrc = 1.695 * 6.2 = 10.51VVce = 20 - Vrc - Ve = 20 - 10.51 - 1.864 = 7.63 VIf you want more precision, you can iterate these results with the other data, like beta. First you calculate the Ib = Ic / beta, it's impact on Vb and Ic, and recalculte all of above. Do it until the results don't change significantly.

author: shanecy
author_rank: Contributor
timestamp: August 06, 2013, 02:48:48 am
content: Could you explain why implementing my solution was incorrect. Why can't I use the formulas above?
Finding the "ADC" chip for a USB microphone project I have  - Page 1
Forum section: electronics / beginners

author: NazmiFR
author_rank: Newbie
timestamp: September 06, 2016, 04:44:38 pm
content: Hi everybody,quick introduction first (I didn't find a section for introductions, sorry if I missed it):Nazmi, a Frenchy obviously (I also have Turkish roots), 17., student in Biology/Geology and prepairing an ham Licence in a club where I learn the basics of electronics with the fellow members, I always liked electronics but started learning only back in 2013-2014 by ordering stuff on ebay and discussing with the people at the club, then I started making prototypes, first I drew on the PCBs myself with a marker and etched with HCl with little success and crappy boards, and now I use a solution of FeCl3I made with iron, HCl and H2O2because Ferric chloride is hard to come by these days (the local electronic store closed back in 2011-2012, so I have to order every little component I need from China...). I love free and open stuff (culture, data, software, speech, and of course hardware), I use KiCAD to design my circuits on a Debian GNU/Linux machine, and I plan, once the few projects I have (not advanced stuff at all, I'm a newbie) will reach a correct level of development to release the design files in an open license so that they can be reused and enhanced.now let's go on the project I'm talking about, it's an amplified microphone using an electret capsule, I'm testing a schematic I found online to see what the really popular and cheap TL062 is capable ofthe board is etched and I'm just missing a few resistors and a capacitor (I have the parts, I just need to see in the mess that is my lab where they are) so soon I'll be able to see the performances of the amplifier, now I'm thinking on the acquisition part. At first I planned on using a cheap USB sound card from China and nowI'm seeking an ADC to fit my need but I can't find a chip with a propper datasheet that explains how to use it and how to connect it (no pinouts nor explanations).I also came across I²S using devices but I don't see how I could use them in my situation (the goal is to have the microphone recognised as a USB Sound card by the PC).So if you have any chip recommandations or any help on how to figure out what I need, I would be really thankfulPS: I know Cortex M0 chips like the STM32 from ST have ADCs and USB device capabilities (along with a lot of other things), do you know if it would be feasible ? (for someone with little experience in programming AVR chips using the Arduino language) to make them act as a USB soundcard (I would be very interested in learning both how to interface things with the ADCs from the chip and how USB works a bit more in depth so if I can learn stuff and make the project better by removing the need of an externa circuit at the same time, I'm happy ^^ )Thanks for having read me and thanks in advance for any helphere is the pic of the prototype (I didn't make the circuit nor the board design, I'll reorganise everything once I'm sure the circuit fits my needs and I know a solution for acquisition (cheap sound card or appropriate chip(s))
Finding the anode impedance of a pentode wired as triode - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: October 03, 2022, 10:00:06 pm
content: I can't find this listed in datasheets, only the pentode anode impedance.I'm specifically looking for a 6AS6 tube wired as a triode, with the suppressor at 0V

author: gbaddeley
author_rank: Regular Contributor
timestamp: October 04, 2022, 11:42:42 am
content: Why 6AS6 in particular? It’s main design merit is to use the screen grid and suppressor grids for additional control / mixing / gating. A pentode like EF86 works well as a triode connected.

author: TimFox
author_rank: Super Contributor
timestamp: October 04, 2022, 04:08:31 pm
content: My guess (not having done the full analysis) is that for a 6AS6 with screen connected to plate, varying the suppressor voltage would change the transconductance more than changing the mu, which is (roughly) governed only by the geometry of the tube.This, of course, would change the plate resistance of the resulting triode.Practical variable-mu triodes (or pentodes) have a non-constant grid-1 winding pitch along the length of the grid, and the result can be considered as low-mu and a high-mu triodes connected in parallel.As the grid-cathode voltage becomes more negative, the high-mu triode cuts off earlier, leaving the low-mu triode active, creating the variable-mu effect.Page 4 of the GE data sheethttps://frank.pocnet.net/sheets/093/6/6AS6.pdfgives rather complete curves of the plate current and screen current as a function of suppressor voltage, along with transconductances.You should be able to calculate the overall anode resistance from the plate and screen currents graphed on page 3.
Finding the brand of a chip and Datasheet - Page 1
Forum section: electronics / beginners

author: triond
author_rank: Newbie
timestamp: September 15, 2013, 05:53:02 am
content: HiHere i have a audio recording devicethat i am trying to mod such changing the firmware,I am not sure if i am reading correctly but its seem writen AC1246D3F474-C on itIts record on a micro SD cardhttp://oi43.tinypic.com/2e33dzs.jpgHere the picture of the pichere some unrelated picture of the circuit that may help youhttp://oi39.tinypic.com/20gd7hg.jpgBackhttp://oi40.tinypic.com/2yjrbww.jpgUp

author: amyk
author_rank: Super Contributor
timestamp: September 15, 2013, 10:09:35 am
content: How new is this device? What is its USB vid:pid? Is there a crystal on the other side (obscured by the battery - what's underneath?) and what is its frequency, if any?I'm guessing it's 8051-based.

author: triond
author_rank: Newbie
timestamp: September 15, 2013, 11:25:49 am
content: No crystal on itthere a brand name JIE LInow we know that JC is not a JC but a JL i guess for JIE LIits say model number AC309N in the usb parameter for the driverfor the vid pid i am not sure where to get iti wonder why there a place for a crystal on the board but there no crystal there

author: Lightages
author_rank: Unknown
timestamp: September 15, 2013, 05:24:35 pm
content: http://www.advanced-tech.com/ic_logos/ic_logos.htm

author: envisionelec
author_rank: Frequent Contributor
timestamp: September 15, 2013, 07:31:35 pm
content: http://www.zh-jieli.com/Their website is mostly inoperable. But you can contact them.

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: September 15, 2013, 09:51:32 pm
content: http://docviewer.yandex.com/?url=ya-disk-public%3A%2F%2FCW3bMs8rMu4YOVHivyctyduJoo%2F1BH7bmnxU%2FhVTCKw%3D&name=AC309N.pdf&c=52362be52612http://docviewer.yandex.com/?url=ya-disk-public%3A%2F%2FftH45m5U6S3ws4VvU7nYEJij3eg5nEMWltlOKwGkhzE%3D&name=40636007AC309N_OTP_REC_v104.rar&c=52362b0c7d5f

author: triond
author_rank: Newbie
timestamp: September 15, 2013, 10:08:58 pm
content: those 2 last link are interesingi wonder if we can download the firmware from the devicethere a files named isd_download.exe i guess its rather to download on the device the firmware or something like thatto get a backup and then try to upload a modified one on it

author: amyk
author_rank: Super Contributor
timestamp: September 16, 2013, 10:48:58 am
content: I found some more info and the datasheet athttp://code.google.com/p/kt-rec-pro/, which has been assembled athttp://www.mediafire.com/?l4442yn98m5cb02for your convenience.As I predicted, it's an 8051-basedQuoteBut it's OTP so you won't be able to change the firmware.
Finding the most suitable short throw/ultra short throw projector with hd color? - Page 1
Forum section: electronics / beginners

author: Lizzie_Jo_Computers_11
author_rank: Regular Contributor
timestamp: February 04, 2017, 08:31:21 pm
content: This topic (for those of you who have been following my other PC related topics) has nothing to do with my computer builds, but an entirely different matter. All help is completely welcome, however.I am looking for a projector, and I have been using them for a while now, but I have run into some problems, and would like to see what kind of advice I can find on choosing the right projector for a future investment.To start off, my budget would be somewhere in the range of $3000.-I have used both the BenQ W1070, and the Acer H6417ST. Now, I was impressed somewhat by the color quality of the BenQ one, but the picture it threw was not suitable for my needs at all. I went on to discover I would need a short throw or an ultra short throw projector, and I eventually found the Acer H6517ST projector. The problem with this projector is that it has a very limited color range. The picture quality is actually sharper than that of the BenQ, and it throws double the size of it as well, but the color issues are what is throwing me off. I know it doesn't have any RGB color wheel to fine-tune, and within its settings there are no known ways to fix this problem. The brightness, whites, and blacks, on the other hand, are great, though.I would really appreciate someone else (who may be more knowledgeable than me), to help me find a projector that is more suitable overall. The requirements are that it is a short throw/ultra short throw (which might be better) and that its color is more acceptable than the Acer I listed, while retaining the ability of deep blacks and bright whites.I'm looking into some Epson models right now, but is Epson even a good idea to begin with? I have had bad experiences with the Epson brand. Cameras, printers, scanners, they have been terrible for me...The Acer runs for about $800, I imagine I can track down a significantly higher quality short throw/ultra short throw projector for around $3000.-These are the specifications of the BenQ W1070, and the Acer H6517ST...http://www.projectorcentral.com/BenQ-W1070.htmhttp://www.projectorcentral.com/Acer-H6517ST.htmEDIT:I am currently looking into this projector here...http://www.projectorcentral.com/Epson-BrightLink_Pro_1450Ui.htmI'm also looking at this one here...http://www.projectorcentral.com/Epson-BrightLink_Pro_1460Ui.htmThey are not released yet, but they will be soon.After looking into the comparison between DLP and 3LCD projectors again, as far as the color goes in the price range, I might be better off with a 3LCD for my intended color correction, while maintaining white/black levels. Any differing opinions?
Finding the output voltage of the TL431 shunt voltage regulator - Page 1
Forum section: electronics / beginners

author: khatus
author_rank: Regular Contributor
timestamp: August 11, 2025, 03:28:40 pm
content: Hello friends,I’m planning to build an adjustable constant current electronic load. For that, I’m following the circuit diagram shown below. To build this circuit, I’m testing it part by part to check the output. But the problem is — I can’t figure out or calculate what the output voltage of this circuit should be. When I built the circuit practically, I’m getting an output voltage of around 0.666 volts. Can anyone help me calculate what the correct output voltage should be?This is the circuit that I’m using as a reference to build mine.

author: xvr
author_rank: Frequent Contributor
timestamp: August 11, 2025, 04:24:20 pm
content: 2.5V * 16K / (16K + 22K) = 1.05VAnd the current through R2+R3 is very small - about 66 µA. The load of your divider must be very high-resistance.

author: magic
author_rank: Super Contributor
timestamp: August 11, 2025, 04:36:46 pm
content: By the way, you don't need that capacitor if you are not planning to draw pulsed or AC current from the reference (and I don't think you are). And while 10μF should be OK, at least with the TI version, certain values of capacitance may cause TL431 to oscillate and likely produce wrong average DC voltage (different than the intended 2.5V).If you are seeing unexpected output from the divider, also measure voltage across the TL431 chip to see if it's working correctly.

author: TimFox
author_rank: Super Contributor
timestamp: August 11, 2025, 04:39:14 pm
content: When the cathode and control pins are connected together, the voltage across the TL431 from cathode (positive) to anode (negative) equals its internal reference voltage, nominal 2.5 V.(Cathode and anode are terms taken from the equivalent Zener diode, and can be confusing.)There is an alternate version, TLV431, with a nominal reference voltage of 1.25 V.

author: Zero999
author_rank: Super Contributor
timestamp: August 11, 2025, 04:50:49 pm
content: The output resistance is equal to the values of the resistors connected in parallel:ROUT= R2||R3 = (R2*R3)/(R2+R3)R2 = 22kR3 = 16kBoth of the above values are in kilo ohms, 1000s of ohms, but we can save entering all the zeros into the calculation and the result will also be in kilo ohmsROUT= (22k*16k)/(22k+16k) = 352/38 k = 9k26This means the voltage will drop by 9.26mV per every 1µA of current drawn.

author: tszaboo
author_rank: Super Contributor
timestamp: August 11, 2025, 04:52:09 pm
content: Quote from: TimFox on August 11, 2025, 04:39:14 pmWhich some companies, in their infinite wisdom also named TL431.And then there is the TL432 which is just a TL431 with different pinout. For some packages. Not all.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 12, 2025, 08:12:12 am
content: R4 and R8 are superfluous.

author: Vovk_Z
author_rank: Super Contributor
timestamp: August 13, 2025, 05:13:42 am
content: If you have 0.66V across TL431 it means you may possibly put it backwards.Or it is TLV431 (but not TL431) and a 1:2 divider after it.
Finding the polarity of a barrel jack - Page 1
Forum section: electronics / beginners

author: shobo
author_rank: Regular Contributor
timestamp: April 06, 2018, 10:18:41 am
content: hey all.i have an old tablet with a barrel jack connector but the charger is missing.althogh i can find a charger on ebay,it's expensive - 5$ plus.i can buy a barrel jack for peanuts and cut an usb cable.my issue is that i cant determine if the power jack should be center positive or not.the tablet can be easily opened and i want to know if the polarity of the plug can be traced with a multimeter .thanks in advanceSent from my SHV-E250L using Tapatalk

author: Ranayna
author_rank: Super Contributor
timestamp: April 06, 2018, 10:41:54 am
content: First, non-tech solution: Check the manual. Any decent device should have this stated there somewhere. That will also help you to confirm the required voltage, since in my experience barrel jacks for 5 volts are rare. Also name the device, maybe someone here knows the polarity.Otherwise, open it up and check connectivity from the jack to any exposed shields. Those are generally at GND, so would be connected to the negative input.EDIT: See the latest EEVBlog (IIRC #1071) for example. At the beginning, Dave shows how he determined the polarity of the barrel connector.

author: shobo
author_rank: Regular Contributor
timestamp: April 06, 2018, 10:46:13 am
content: Quote from: Ranayna on April 06, 2018, 10:41:54 amThanks!
Finding the Supply Current - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: August 28, 2024, 09:31:39 am
content: I am planning to use two modules and need to calculate how much current is required for power supply for these components.1. C10GS-GNA4H2.https://www.codico.com/en/white-beet-ei-evse-embedded-iso15118-module3.https://www.microchip.com/en-us/tools-resources/reference-designs/wireless-som-reference-design(This SoM module)Unfortunately, I am not able to get the supply current information. Can someone tell me how to find the supply current information for the above 3 devices?
Finding your posts??? - Page 1
Forum section: electronics / beginners

author: SLJ
author_rank: Frequent Contributor
timestamp: November 08, 2012, 02:05:11 pm
content: OK, I've searched but I don't find a way to see a complete list of topics I've posted in. Might come in handy a few months down the road.I found the list of topics with new replies but nowhere can I find a list of all topics I've posted in.Tried searching my user name but that only shows a partial list.Did not find anything when searching the help section either.Anyone?

author: Monkeh
author_rank: Super Contributor
timestamp: November 08, 2012, 02:17:26 pm
content: https://www.eevblog.com/forum/index.php?action=profile;area=showposts;u=27543I see 17 posts. What's the problem?

author: SLJ
author_rank: Frequent Contributor
timestamp: November 08, 2012, 02:30:09 pm
content: Not a problem now as after seeing your link I spotted the option in my profile under the avatar. Don't know why I did not see it before. Thanks.
Fine pitch connector - durability - Page 1
Forum section: electronics / beginners

author: Tantalum
author_rank: Regular Contributor
timestamp: December 29, 2015, 12:40:51 pm
content: HelloI'm searching for FFC connectors or other like the Pico-Lock from Molex, which support a high number of plug/unplug cycles.I can understand that such connection can't last as long as a standard 2.54 pin header, but clearly 10-20 cycles is not enough :-/Does that exists?Thank you!