hybridfree/eevblog-posts huggingface dataset:
Large perf/proto board - where do you get it? - Page 1
Forum section: electronics / projects

author: aargee
author_rank: Frequent Contributor
timestamp: March 11, 2015, 02:32:52 am
content: Hi all,I'm looking for large perf/proto board of around 30cm x 30cm (1 sq ft) or larger.Either FR4 or paper/bakelite type, 0.1" pitch, preferably with copper pads on one side (not strip board).Any reasonably cheap sources (this is not for a life critical application and/or doesn't need engineering standards).EBay doesn't seem to go that large.TIA

author: tggzzz
author_rank: Super Contributor
timestamp: March 11, 2015, 09:43:30 am
content: Quote from: aargee on March 11, 2015, 02:32:52 amWhy don't you simply mount several smaller boards edge-to-edge on some form of carrier? That would have the advantage that you can debug each subsection of your circuit separately.I would be interested to see the flexibility/integrity of a pcb that size that is completely full of holes without any other supporting structure such as copper foil.

author: aargee
author_rank: Frequent Contributor
timestamp: March 12, 2015, 12:42:29 am
content: I don't really want to use the board area fully, but as a chassis top for mounting components on.I have 20cm Vero type strip board which will be a fallback but not as visually appealing as a one piece solution.RS and Element14 have boards but very expensive. e.g.(http://au.rs-online.com/web/p/matrix-boards/3917327/)
Large press fit terminals and board flex - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: October 02, 2021, 10:51:11 pm
content: Does anyone have experienced with large 25pin (150A) press-fit terminals and stopping PCB flex.I'm concerned the board is flexing too much and could cause SMT part failures.For prototypes I have been pushing them in manually with vice by putting a block of wood behind PCB.I suspect some sort of a metal jig is required to clamp and hold the PCB flat as they are pushed in but I have no experience with press fit terminals.I could make the holes a bit larger to reduce stress on PCB but that would make the holes out of spec from what the DS says. They do seem tighter than I would have thought needed but they are correct. (The pcb house was told the spec and that they were press fit holes when PCB was made)

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: October 03, 2021, 02:13:35 am
content: Hi,I have some experience with 25-pin press-fit terminals.I made a backing block like this:I have made them out of 3D-printed plastic, with a high fill ratio and out of 6061T6 Aluminum. The threaded holes are used align the blocks on a tooling plate.The terminals must be inserted in one continuous motion.Regards,Jay_Diddy_B

author: Psi
author_rank: Super Contributor
timestamp: October 03, 2021, 02:47:08 am
content: Quote from: Jay_Diddy_B on October 03, 2021, 02:13:35 amThanks.Using the vice they definitely were inserted in 3 or 4 starts/stops. So that is probably another issue I have.I will be buying an arbor press as soon as the lockdown level changes and I can buy one.
Large spring-loaded connectors with about 5 mm of stroke - Page 1
Forum section: electronics / projects

author: joelsa
author_rank: Newbie
timestamp: December 07, 2021, 07:15:30 pm
content: Hi everybody,I am looking for large pogo pins, or spring-loaded connectors, with a large amount of stroke/travel (about 5mm is needed), e.g. similar to this one:This is 5 mm grid paper, so the total length is about 15 mm, the stroke is almost exactly 5 mm. I feel quite lost here because I have spent hours clicking myself through the websites of the large distributors (Digikey, Mouser, etc.) and also sifting though the catalogue of Mill-Max, but I haven't found anything that comes close. Most connectors there are much thinner and only have up to 3 mm in stroke. This is particularly frustrating as I have seen similar sized Pogo-pins in the wild, for example they are used on this LTE-Module that can be put onto a Raspberry Pi Zero:Does anybody here have a clue where I can look for such large pogo-pins, or did any of you already work with similar connectors in the past?Any hint is greatly appreciatedRegards, Joel

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 07, 2021, 07:46:19 pm
content: Tryhttp://www.coda-systems.co.uk/catalog/index.html

author: joelsa
author_rank: Newbie
timestamp: December 07, 2021, 08:56:25 pm
content: Thank you very much Mike!The site does indeed look very promising and I'm sure I'll find something fitting there.
Large Surface Mount Tacticle Switches - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: August 02, 2014, 10:18:57 pm
content: Does anyone know of a good brand that sells large surface mount momentary switches.I really like these by NKK but they're through-hole. The switches I like are on pages J38 and J39 (PDF page 36). The actuator is about a half an inch.http://www.nkkswitches.com/pdf/tactiles.pdfI'm just at a complete loss. It seems to get something large it either has to be a panel mount behemoth or a through-hole component.Does anyone have recommendations with a brand that they wouldn't mind sharing?Regards,

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 02, 2014, 10:26:35 pm
content: MEC do somehttp://www.mec.dk/12-26847-Series-details.php?id=292

author: Pack34
author_rank: Frequent Contributor
timestamp: August 03, 2014, 03:04:54 pm
content: Thanks Mike!
Larry Load Circuit diagram - Page 1
Forum section: electronics / projects

author: johnh
author_rank: Regular Contributor
timestamp: February 18, 2022, 12:18:14 am
content: Does anybody have a copy of the circuit diagram, described by John GuyIn this articlehttps://www.electronicdesign.com/technologies/displays/article/21772797/resistive-dummy-load-draws-constant-current-from-12-to-50-vBookmarked the article after seeing it in someone twitter feed, awhile agoShould have saved the article and diagram

author: Kim Christensen
author_rank: Super Contributor
timestamp: February 18, 2022, 04:58:25 am
content: Googling turned up this PDF:

author: johnh
author_rank: Regular Contributor
timestamp: February 18, 2022, 05:42:15 am
content: John Guy has made available gerbers on Oshparkhttps://oshpark.com/shared_projects/2RLfokAbWith some more modern componentsAll component values and reference designators changed from article though. All load resistors are off PCB too. Use 1% through hole resistors mounted to output banana jacks. U1 is REF3012, U2 is OPA313, and U3, optional, is TPS3702AX18DDCT for checking battery voltage. This version will work off 2 x AAA batteries.
Larson Effect circuit - Page 1
Forum section: electronics / projects

author: naimis
author_rank: Contributor
timestamp: February 24, 2013, 05:02:42 pm
content: Something I've been fiddling with off and on over recent weeks. Who hasn't done something like this? Anyway, I built it with spare parts, basically. Stuff I had sitting around or had dug out of the trash. The plan is to put it on a protoboard and stick it inside my PC at work, which has this nice light pipe that goes the full width across the front of the case. Unfortunately I can't take a picture of it there. The breadboard was to make sure my circuit design actually worked :-)

author: naimis
author_rank: Contributor
timestamp: February 24, 2013, 05:03:40 pm
content: On a side note, I noticed that for embedding youtube links to work, it must use http: rather than https:
Laser Arcade Game Project - Page 1
Forum section: electronics / projects

author: Quaq
author_rank: Newbie
timestamp: April 29, 2016, 06:39:38 pm
content: Hey guys,Just wanted to show off a project that some fellow students and I have been working on.It's a big wooden board full of programmable LED strips and an array of infrared sensors. The goal is to allow up to four players, each holding one of my 3D printed "laser guns," to target the sensors and set off pretty patterns of LED lights (and maybe sound effects too). The reactions will be made unique to each player through multiplexing. The logic is done with a TI Tiva C microcontroller, multiplexors, and IO expander ICs. We've been coming up with alternate "game modes" to program into the Tiva, like a target practice mode or perhaps a competition with the other players to fill the board with your color by a time limit.There's our breadboard prototype circuit on the left. We're testing some code before putting the rest of the LED strips on.Here is half of my 3D printed gun with a protoboard circuit inside. We have several differently colored guns for the players.We drilled holes through the board and set the IR sensors in the holes on the backside. This helps to isolate the sensors from outside interference.Here's the team hooking up all the LED strips to the front.It's not done yet - we are probably going to spend the whole weekend debugging the codeLet me know what you think!
Laser cutting holes on acrylic - Page 1
Forum section: electronics / projects

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: February 12, 2020, 06:25:40 am
content: Friends,I'm trying to cut some panels using acrylic sheets on laser machine. The panel is rectangular and has several holes in it. The laser will do multiple passes at speed of 100 to cut that shape. The problem is that sometimes, the entire panel falls off the sheet, before the holes are completely cut. This leaves the holes un-finished and has to be manually cut out from the panel.If there any software which will ensure that the holes are cut first followed by the panel outline?I am using EleksCAM software currently.

author: moffy
author_rank: Super Contributor
timestamp: February 12, 2020, 07:13:40 am
content: Can't you split the job into 2 parts?1. Produce your drawing for the holes only and cut them out.2. Produce a drawing for just the final outline then cut them out.

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: February 12, 2020, 07:20:35 am
content: Quote from: moffy on February 12, 2020, 07:13:40 amGreat and simple idea... Will try...

author: Fred27
author_rank: Unknown
timestamp: February 12, 2020, 12:29:11 pm
content: I don't know EleksCAM but most CAM software will let you define what order to do operations in. You shouldn't have to split it into 2 jobs - just 2 operations within the same job.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: February 12, 2020, 01:15:11 pm
content: Use layers.... split your shapes into different layers in your DXF and then the cutter will cut the first layer, then the second layer etc...So work you way outwards... cut the holes first...likewise for etching... etch first... then cut... then cut outside... etc
Laser diode identification - Page 1
Forum section: electronics / projects

author: AlcidePiR2
author_rank: Regular Contributor
timestamp: April 18, 2020, 01:21:29 pm
content: Dear All,I made a mistake. I desoldered these laser diode ( from a HP Laser printer board RM1-4756) before noting the pinout.In any case, this would not have been sufficient to identify the laser diode.Can any of you can help me on this ?- identification of the laser diodes ?- identification of the pinout ?And as well for thephototransistorphotodiode ? written 9Z AL ??Thanks

author: AlcidePiR2
author_rank: Regular Contributor
timestamp: April 24, 2020, 04:08:07 pm
content: Really ? Nobody on this one ?I have searched on my side but I am quite frightened to see the variety of pinouts for laser diodes.I see also that many have reverse voltage limit of only 2 V, so I dont want to try too much randomly.Best Wishes to all.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 24, 2020, 04:33:38 pm
content: http://repairfaq.org/sam/laserdio.htm#diodct2Quote

author: ChristofferB
author_rank: Frequent Contributor
timestamp: April 24, 2020, 04:36:10 pm
content: They have no markings at all?Why dont you look up one of the 4 driver ICs and use its pinout to find what connects to what?Alternatively make a current limited 2V supply and just try all combinations. (Without shooting your eye out!). Sacrifice one of the diodes. I'm not even sure it would damage it to be reverse connected briefly.

author: Gyro
author_rank: Super Contributor
timestamp: April 24, 2020, 04:59:06 pm
content: Note that bare Laser diodes like that are very ESD sensitive. You need to handle them with care.The 8 pin "photodiode" is actually an IC with active circuitry on it. It looks as if pin1+pin5 and Pin 3+6 are supply and ground (but not clear which polarity).. Pin 2 looks like the output, and pin 4 either a power-on reset or an internal bias supply (capacitor connected to supply or ground).

author: AlcidePiR2
author_rank: Regular Contributor
timestamp: April 25, 2020, 04:07:32 pm
content: Quote from: NiHaoMike on April 24, 2020, 04:33:38 pmThanks a lot. The web site is very informative. And the method to test very simple and effective.I used a small 650 nm laser diode to test, at low power, otherwise it saturates both sides.I could have ~ 300 mV on one side ( thus PD) and only 5 mV on the other ( LD).Now I can go further and test the polarity.

author: AlcidePiR2
author_rank: Regular Contributor
timestamp: April 25, 2020, 04:10:33 pm
content: Quote from: ChristofferB on April 24, 2020, 04:36:10 pmThis is of no use. I dont know the side it was soldered on the board. Otherwise I would have just read what is written.I can do that to check the polarity.
laser diode replacement that has a earthed or floating body and 0.4inch thick? - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: April 28, 2018, 06:43:08 pm
content: I made a little antenna aimer using a laser. It is quite nice, it has a big over sized heat sink, a power system capable of handling way more voltage then required, a good design electrical protection system, user power control, robust shielding and good mechanical design that can be water proofed.I put a fair bit of work into it and used quite a valuable heatsink/mechanical work to attach two linear regulators and a diode.Well, unfortunatly I damaged the diode, which was chinese, because I twisted the PCB attached to it during removal and destroyed a bond wire (completely unacceptable mechanical design on their part to allow a component lead to rotate freely and tear a fuckin bond wire, every transistor I ever used will sheer right at the mother fucking can interface, but enough of that bullshit).The big problem for me however, is the fact that the body of the diode is reference to a positive voltage, I forgot about this. While it was not a problem to float my regulators using sillpad and special screws with plastic heads and heat shrink over the threads, I am still faced with the problem of having a heat sink that will be at laser voltage, even if I buy a replacement laser.Now, without having to do a whole mechanical redesign (I spent too much time on this already), can anyone recommend a laser diode with optics that would fit into my machined holeThis is the laser diode / optics I used:http://www.dx.com/p/100mw-532nm-green-laser-module-3v-11-9mm-26890Yes, the control electronics and heat sink cost alot more then the shitty diode at this point. But does anyone have a replacement for that part (minus the control electronics and shit mechanical design) that will fit into the same form factor but have a earthed or floating case?I really like what I did so far, it is tolerant to 80V indefinably with high ESD protection, will run at like 20V in the hot sun, has a big power adjustment knob, good space for high quality batteries or external power source, can be in the rain.It is meant to attach to microwave directional antennas with narrow (3deg) beamwidth.I don't want to float the whole thing because of moisture, it would require working with plastics too much (the antenna it will be mounted to is earth referenced) if it is to be capable of surviving in the rain.And my mechanical design is tight, I can't rebore the hole to a much larger diameter due to the proximity of the linear regulators. maybe I can go like 0.1 inch wider diameter.

author: CopperCone
author_rank: Super Contributor
timestamp: April 28, 2018, 06:56:42 pm
content: also it can be stronger then 100mW I don't really carealso would prefer to have a photodiode for feedback but its not a necessity.
laser diode - Page 1
Forum section: electronics / projects

author: decoevvblog
author_rank: Newbie
timestamp: February 20, 2023, 02:49:59 pm
content: Hi,I wanted some help kindlycan i use the same digital potentiometer for 9 laser diode?obviously I will have a single setting for all 9...

author: moffy
author_rank: Super Contributor
timestamp: February 20, 2023, 09:33:19 pm
content: The connection of LD1 is curious, especially what I assume is the photodetector connection to ground? Yes you can use the same output from the digital potentiometer to drive other laser diodes via the LM324, as the +ve input is relatively high impedance, the most you would need to worry about is input bias currents into the LM324s creating an offset in the digital pot.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 21, 2023, 01:50:01 am
content: Put a 100k or so pulldown on the noninverting input of the opamp to ground, so that a bad connection won't cause it to go to max current from bias current.
Laser Pointer Teardown and Test Video - Page 1
Forum section: electronics / projects

author: rsduhamel
author_rank: Contributor
timestamp: July 25, 2018, 11:25:22 pm
content: I uploaded a new RSD Academy video yesterday. I need to know the best voltage range and current requirement for a laser module that I plan to use for a laser communicator project. I tore open (literally) a laser pointer and tested it. Turns out that it has a good linear response (voltage to light output) between 3.5 volts and 5 volts and requires 50 mA at 5 volts. Here's the link:https://youtu.be/Pbrhays1m18

author: JS
author_rank: Frequent Contributor
timestamp: July 26, 2018, 01:59:35 am
content: Hey usually respond yo current, so your linearity is probably a series resistor with the laser, wich starts at 3.5V and the current raises linearly from there thanks to the resistor.JS

author: james_s
author_rank: Super Contributor
timestamp: July 26, 2018, 04:43:00 am
content: Laser diodes have gotten really robust. I remember when visible red laser diodes were still quite new, they cost around $200 each at the time and there was a very narrow gap between when lasing would start and the point where catastrophic optical damage would occur. They required active control using a a built in photodiode to control the current. Times have changed.

author: rsduhamel
author_rank: Contributor
timestamp: July 27, 2018, 02:23:22 am
content: I remember those days too. Scared me away from messing with laser diodes. Maybe modern laser diodes have built-in protection.
Lashing up a HV Probe - Page 1
Forum section: electronics / projects

author: icon
author_rank: Regular Contributor
timestamp: October 10, 2012, 03:28:20 pm
content: HiI want to check a 1700V supply on a scope I'm trying to fix. I have it in mind to make a chain of nine 10Meg (250V-rated) resistors. I could then rely on the 10Meg input impedance of the Fluke 87V to give me a 10:1 divider, or I could add another 10Meg resistor and tap off at that point to the meter and double(-ish) the figure shown on the meter (the 'bottom' of the chain going to ground, obviously)Other than the obvious ("don't"), any thoughts either way?CheersJohn

author: Neilm
author_rank: Super Contributor
timestamp: October 10, 2012, 08:25:52 pm
content: Is this a DC signal or AC signal?If it is AC then you may end up with some weird issues. Capacitances that are too small to worry about normally can turn up and cause all sorts of problems.I would add the extra 10Meg resistor as it will mean that if the meter became disconnected accidentally, nothing would be damaged or become dangerously charged.YoursNeil

author: SeanB
author_rank: Super Contributor
timestamp: October 10, 2012, 08:41:03 pm
content: Do not trust the quoted meter impedance. Use a 1M resistor and 10 series resistors instead, then you will only read roughlt 1/100 of the input voltage. The 9 series resistors must be cleaned after soldering with IPA and dried and baked to remove moisture, then encapsulated in high voltage silicone to prevent flashover.

author: icon
author_rank: Regular Contributor
timestamp: October 10, 2012, 09:18:44 pm
content: HiThanks for the advice - I should have said, it's 1700V DC, though I might just check for 50Hz ripple on a scope. I will go for the 1/100 idea. Can metal film resistors withstand 100degC for a reasonable period of time without changing value significantly, I wonder?CheersJohn

author: TriodeTiger
author_rank: Regular Contributor
timestamp: October 10, 2012, 10:07:12 pm
content: Quote from: icon on October 10, 2012, 09:18:44 pmThat's what ppm/c (or was it temperature coefficient) figures are there for!Where are your 100C calculations coming from? Why does it need to be this hot? Seeing only 1.7kV on a 10meg 1/2W metal film resistor would be within its rating.

author: icon
author_rank: Regular Contributor
timestamp: October 11, 2012, 07:03:29 am
content: Quote from: MmCoffee on October 10, 2012, 10:07:12 pmFrom the boiling point of water.John
Last project of the year, first one strictly 4 hobby & fun - Page 1
Forum section: electronics / projects

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 31, 2011, 06:03:15 pm
content: The arc reactor has two strands of 5 hi-brightness leds in 1206 package.Power comes from two AA cells and a TPS61041 boost converter circuit.This regulator uses a current sense resistor as the feedback signal so itbecomes a current source of ~30mAmps. The LED chains are paralleledwith two 22ohm resistors, so that each gets about 15mAmps.Using a doublesided finepitch protoboard (1.27mm spaced holes), the circuittakes less than a square cm, including the tiny on/off switch.Truly a nerd, the real challenge was to sew the stuff onto the shirt. Ofcourse I had to make the mistake of using too small piece of cardboard, anddiscover that I accidentally stitched back and front of the shirt together onone of the loops.Scissors and superglue!
Latch an AC Relay - Page 1
Forum section: electronics / projects

author: rupefelo
author_rank: Newbie
timestamp: June 10, 2015, 06:30:16 pm
content: So, I've been trying to make a safety "switch" for pump, incase of a power outage it doesn't automatically start working again, you need to press a button to "arm" it again.I've been trying to make a 220V AC relay latch, but I haven't had any sucess. Can you guys help me with a schematic or something? Is it even possible to make?Also, if you have any better ideas, feel free to share themThanks in advance

author: nickn4
author_rank: Contributor
timestamp: June 10, 2015, 06:58:10 pm
content: You want a manual or digital switch, that resets after a power outage, correct?edit; welcome to the forums btwnick

author: rupefelo
author_rank: Newbie
timestamp: June 10, 2015, 07:02:31 pm
content: Well, I would prefer manual. But thats it.
Latch switch - Page 1
Forum section: electronics / projects

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 14, 2014, 02:35:16 pm
content: Here is a latch switch circuit from a EEVblog video.How can I create a push button contact switch in LTSpice?I used a voltage pulse but it does not create the effect.Rename the file to LatchPowerOn-Off.asc to use it.JP

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 15, 2014, 03:58:31 pm
content: I tried the csw ... it seems to work....Remove the .txt extension to get the asc LTSpice file.
Latch-Up? - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: June 06, 2019, 10:25:17 pm
content: Simple little 555 circuit below is acting up. Most of the time the 14s timer operates as expected, once in a while it stops early. I thought I could rely on the ESD diode at pin 2, but looks like that little spike is enough to cause problems.Agree/Disagree?

author: dmills
author_rank: Super Contributor
timestamp: June 07, 2019, 01:29:12 am
content: Something odd with the U8-2 trace as I would expect the rising edge of 10m to cause it to shoot up from 5V to something higher, and I would expect the falling edge to cause it to go low before slowly ramping back to 5V.Not what we are seeing.Regards, Dan.
Latching octal bus transceiver with 3-state outputs? - Page 1
Forum section: electronics / projects

author: maginnovision
author_rank: Super Contributor
timestamp: June 04, 2018, 08:08:48 am
content: I'm looking for what could best be described as a latching octal bus transceiver with 3-state outputs. I'm just not sure if such a thing exists. I'm using a SN74AHCT245 and it works but It'd be helpful from a software point of view. What I have to do now is receive signal from cpld, send a signal back saying it's ready, and then send another signal to basically reset the logic. Basically I could save 7+cycles every time, which is quite alot when the functions are only about 25 clock cycles from before entering, to having returned and ready again. Preferably AHCT and small surface mount package. Any ideas?

author: TurboTom
author_rank: Super Contributor
timestamp: June 04, 2018, 09:16:00 am
content: Did you have a look at the 74xxx646 / 74xxx8646 series? Though quite expensive, they may do what you need.http://www.mouser.com/ds/2/149/74ABT646-196142.pdfCheers,ThomasEdit: Link added

author: Buriedcode
author_rank: Super Contributor
timestamp: June 04, 2018, 02:26:05 pm
content: Do you mean like the 74xx573? That's an octal D-type transparent latch with tristate outputs. AHCT here:https://www.digikey.co.uk/number/en/texas-instruments/296/74AHCT573/6423

author: maginnovision
author_rank: Super Contributor
timestamp: June 04, 2018, 04:35:36 pm
content: Quote from: TurboTom on June 04, 2018, 09:16:00 amIndeed, that does exactly what I want at a 1.25 or so over what I have. Might have to try a few.Quote from: Buriedcode on June 04, 2018, 02:26:05 pmI'm using those elsewhere on the board but the transceiver is required since I dont own the attached bus and need to instantly connect or disconnect from it electrically while using it in either direction. It's not super high speed but has no margin that the mcu can manage(~30ns). Thanks for the suggestion though.
Latching Pmos circuit for high voltages - Page 1
Forum section: electronics / projects

author: 2printbeta
author_rank: Newbie
timestamp: September 26, 2022, 11:27:47 am
content: Hello EEVBlog members,I am currently trying to design a latching pmos circuit to control the power to a board. The circuit should be power up when a separate input goes above x voltage, and it should power-down if my microcontroller pulls a pin high to switch itself off.The difficulty is here, that the power input (and the on-pin) can have 6V-48V with up to 80V peaks, so the mosfet gates need to be protected. And the circuit should consume as little power as possible.I made a first simulation of this in LTSpice (all parts are preliminary and just chosen from what was available in LtSpice).Now the question is, how high or low can i safely tune the power consumption, before i get problems and stability issues. And are there any other hints or tricks ?I would really appreciate any input on this, as i am not really experienced in this type of electronics.

author: jwet
author_rank: Frequent Contributor
timestamp: September 26, 2022, 04:34:02 pm
content: I don't know if you need flea power in the off mode or on and off modes- you show a 100 ohm load which sound like some real current when on. You might have gone a little overboard with the 1M pull up- this is only active when the system is on. The zener sub threshold leakage is about.1 uA- I assume this is over temp but might double check. The BSD123 zero gate leakage is low at room but can be 60 uA at 125 C but might be 10 uA at high ambient like 40 C- kind of messy. (this leakage doubles every 8 degrees C, so you'd have 4x of your room value.) I'm not so worried about stability as in oscillating but more in bias stability over temp. Overall I think it looks pretty good but I would not try to dial down the quiescent much more. Take account for when you need the low low Iq- if you can burn a bit when the system is on, it would make for a less finicky system. The problem with very high R values with high voltage is the slightest board contamination can create a leakage path and mess up operation. If you really need to have these high Z's consider conformal coating. Good luck.

author: 2printbeta
author_rank: Newbie
timestamp: September 27, 2022, 10:43:55 am
content: Thank you for the reply. Especially the remark about the leakage current of the BSS123. I will have to check the datasheets of those more throughly.The 100ohm load was just a standin for simulation. The microcontroller board which will be powered by this, only consumes about 2mA in normal mode an down to about 0.5mA in a active standby mode. The whole things is battery powered and this circuit is intended to protect the battery if the voltage gets too low. So i really need the "fea" power in off mode, but it should not take much power in on mode.The 1Meg Ohm pullups are probably a bit too high, so i will try to calculate a energy budget i can spend on this.
Latchup in GSM Module - Page 1
Forum section: electronics / projects

author: itdontgo
author_rank: Regular Contributor
timestamp: July 15, 2013, 06:38:01 am
content: We've had a few boards back with a short in the GSM module; we're talking say 1 in 100. We've built about 1000 of these boards and I have about 10 down the side of my desk with latched up output amps.At first it was assumed that this was caused by a surge making the voltage regulator overshoot or from customer feedback it sounds like a few of them connected it to low voltage AC which eventually blew the module. When we looked at the scope though the power supply appears to perform well with very little ripple.However I come across one unit which worked fine - until you called the PCB and the board started using a lot of power. The output power amp chip (TriQuint TQM6M4068) latches. The voltage on the board fails and this chip heats up - only releasing when the power is cycled. I'm now surmising that this is what happened to the other boards - the difference being their operator didn't switch them off and just let the modules cook!http://www.triquint.com/products/d/DOC-A-00000735The fact I have a board which can recreate the fault - if it is the same fault - on demand is excellent!First thing was to connect a Li-Ion battery directly to the module and RF ground to rule out power supply issues. The fault still occurred. Beyond this I'm assuming the fault lies within the Quectel module. Every other input to the module goes through a 3v regulator. All I can think of now is to get the module off and put it back in the reflow oven to make sure the ground connection is properly soldered. I've done this before with a CCTV camera board that only worked when you twisted it.I'm all out of ideas! Can you tell?

author: itdontgo
author_rank: Regular Contributor
timestamp: July 17, 2013, 12:40:57 pm
content: For anyone designing with the Quectel M95 GSM module - I recommend you keep your voltage to about 3.7-3.8v. Looking back at the older boards which never had a problem they ran at 3.8v. The Quectel datasheet reference design was 4.2v so we changed the design to suit. The faulty unit latches up at this voltage. I don't see an overshoot in the power supply but it could be too fast for the scope I'm using (200MHz though). At 3.8v the faulty unit is fine.Strange as the PA chip should go up to 4.5v:TQM6M4068.pdf Datasheet

author: itdontgo
author_rank: Regular Contributor
timestamp: July 17, 2013, 12:44:12 pm
content: Oh and the reason it didn't work with the lithium battery... carelessness with the soldering iron shorted the audio output which locked up the baseband chip! Doh!

author: KJDS
author_rank: Super Contributor
timestamp: July 17, 2013, 12:47:34 pm
content: The power amp on every GSM output module i've looked at is more of an injection locked oscillator than an amplifier. it's very very common for these to oscillate unless a lot of care is taken with the grounding, shielding, ramp up and down, input and output matching etc.
Latest project in the lab - Page 1
Forum section: electronics / projects

author: Messtechniker
author_rank: Frequent Contributor
timestamp: December 14, 2020, 06:31:26 pm
content: Since, because of home schooling, webcams and stuff are sold out here in Germany, I gave my not much used webcam with mic and phones to the next door neighbors boy. But to have the old setup ready mainly for testing I had a jolly good look into my junk box. Found a webcam for W7. Yay! Could make it run under W10 but without sound.So next a deep look down my microphone locker. Found a crusty old base, a gooseneck and a simple M-Audio mic and a simple home-grown NE 5532 based mic pre. Put it all together with a little paint for the base. See pic. So now I'm back in business.
Latest Project - Outdoorising an Indoor Smoke Machine - Page 1
Forum section: electronics / projects

author: kolbep
author_rank: Frequent Contributor
timestamp: November 10, 2018, 04:06:13 pm
content: My latest project (and this one has a deadline of less than a week).Taking an Indoor Smoke Machine (like you use in a club), This one has an RGB Led Array to light up the fog.Splitting the Unit into 2 separate parts, automating the firing with an Arduino and Mains Timer,Sealing it to work outdoors.Video of the 1st Part is here :Enjoy, and if you do, please subscribe to my channel so that you can see when I have finished it.P

author: kolbep
author_rank: Frequent Contributor
timestamp: November 19, 2018, 05:48:18 am
content: And Part 2 has just gone up :https://youtu.be/bNY-nas5nQw
Latest Project -- Vibe2Tone - Page 1
Forum section: electronics / projects

author: yardleydobon
author_rank: Newbie
timestamp: September 17, 2011, 02:02:56 am
content: I often forget to turn on my cell phone's ringer when I put it on the charger and even if I do I still can't hear the phone when I'm out of the room. So I made a little device that plays an audio alert when it detects the cell phone is vibrating. I think this sort of device could be useful for the hearing impaired, too. I used a MOSFET driver to amplify the PWM audio output from the microcontroller. Feedback is welcomed!Here's the video demonstration. It's a submission for a contest, so it's a bit over the top. Checkout the description for a link to the source code and schematic. Please give it a "Like" on youtube if you like it, because that's part of the scoring.Here's the project I based mine on.http://elm-chan.org/works/sd8p/report.html

author: SgtRock
author_rank: Unknown
timestamp: September 17, 2011, 03:08:57 am
content: Dear Yardleydobon:--Being hearing impaired myself, I find your project very interesting. I can hardly hear my Fluke 87 continuity beeper any more. Do you have any off the top of your head ideas for that. Also, could you please tell us what music you are using, it is very good, and funny."Three weeks in the lab will save you a day in the library every time" Stanley Williams, HP LabsBest RegardsClear Ether

author: yardleydobon
author_rank: Newbie
timestamp: September 17, 2011, 03:50:33 am
content: I'm no expert but I'm guessing you have trouble with the higher frequencies. You could probably make a circuit that listens to your meter and outputs a louder, lower pitched tone. Or listens to the meter and flashes a bright LED; something that would be easier to spot than a change on the meter's display with your peripheral vision. The music is four different unrestricted sound files I pulled off the internet. At first there was a fifth sound which was the communicator noise from Star Trek TOS, but I took it out because of the contest rules. It made me sad to do that because it sounded so cool.
Laying out a uC - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: November 16, 2012, 01:15:51 am
content: So when laying out board with SMD uCs using both the ADC and switching signals, what order generally works best?e.g. do you start with decoupling caps, then the analog side and any associated guard tracks, then move onto the digital stuff etc.Obviously there's exceptions. And I guess there'll be cases where there's clear high priority signals... But just wondering if there's generally a "best" way to start?

author: Psi
author_rank: Super Contributor
timestamp: November 16, 2012, 02:40:40 am
content: Most mcu datasheets have a recommended track/groundplane layout for around the ADC pins.

author: richcj10
author_rank: Unknown
timestamp: November 17, 2012, 01:41:01 am
content: If it is a 4 layer, I put the caps under the uC on the bottom layer.If it is a 2 layer, I put the caps next to the pins and route out from there.

author: Kremmen
author_rank: Super Contributor
timestamp: November 17, 2012, 12:56:08 pm
content: I have had good success with 2 layer boards by placing the bypass caps directly under the MCU power pins on the board back side and then connecting with minimum length vias to the power pins. The other end of the cap just goes to the ground plane that is flood filled all over the back side.
Layout Advice for PoE / GB Ethernet - Page 1
Forum section: electronics / projects

author: ElDuderino
author_rank: Newbie
timestamp: September 26, 2020, 12:39:04 am
content: Hi all, first post here and happy to join!I'm working on a space constrained design. This PCB has GB PHY, Pulse H6062NL magnetics, a Silvertel Ag9900 PoE module and a DC-DC converter. Can anyone offer some design advice for the best way to split the gnd plane and pours here on this 4 layer PCB?The via stitching under the around the PoE module is for thermal management. I cutout the GND pours on the top/bottom where the high voltage components reside.Thanks!!
Layout: LVDS on top layer?  - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: February 23, 2018, 08:15:30 pm
content: I'm working with a new sensor that will send LVDS data from a sensor to an FPGA. I believe that you would typically route these on internal layers to mitigate crosstalk, however, the routing is less than half an inch. Would it be safe to keep the traces on the top layer? Or do I really need to dodge down to an internal layer for that half-inch?

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 23, 2018, 08:28:23 pm
content: IMOP better to avoid the impedance disruption through the via's as long as the next layer down is a solid referance plane under the micro-strip and either side of it. Of course you will have to calculate the impedance according to the deilectric thickness.

author: ejeffrey
author_rank: Super Contributor
timestamp: February 24, 2018, 06:37:15 am
content: Its fine to run LVDS on the top layer. You just need to make sure your impedance is correct and the lengths are matched.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 24, 2018, 06:43:07 am
content: My Digilent Atlys has quite a few LVDS pairs running on the top. As it's a differential signal, EMI is much less of a problem.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 24, 2018, 10:04:41 am
content: Quote from: ejeffrey on February 24, 2018, 06:37:15 amHeck, with a run that short, even that won't matter, at least unless it's gigabit and time-critical.Tim

author: Pack34
author_rank: Frequent Contributor
timestamp: February 24, 2018, 03:26:41 pm
content: Quote from: T3sl4co1l on February 24, 2018, 10:04:41 amOnly 300Mhz.Thanks guys!
Layout Tips - Page 1
Forum section: electronics / projects

author: mscaff
author_rank: Newbie
timestamp: June 10, 2019, 06:07:35 pm
content: Hi,I'm new to the forum and not sure if this is the right place to ask this, so, sorry if i'm at the wrong place.I'm layouting a new PCB that has several power switched and linear power supplies a microcontroller and several ADCs.After reading a lot, it seems that there is no unanimous answer for my questions so, I'll ask here and hope to get a better understanding about what should I do.To be honest I think that it would be a great topic for a new video.My question can be divided in 2 parts.1) About the switched power supplies. Which is best?a) To route for instance all the signals the shortest and widest in the top layer and connect with several vias to the plane in the inner layer just in 3 points (Vin, Vout and Ground). The idea here is to avoid spreading the noise and high currents from the PSW to the rest of the planes.b) To use as much layers as possible in parallel. The idea here is to reduce the impedance as much as possible.It seems to me that the 1st options is best, but I found a lot of conflicting information around.2) In this board I have 4 x 24 bit ADC. How do I connect them?a) Some say to just use a single solid ground plane and just place the Analog parts away from high speed and high current devices or in the path between them and the power supply. This is the easiest to me.b) Some say to split the digital and analog planes and just connect them in a single place in the power supply. But since both of my supplies (3V3dig and 5Van) are created from the same input, they share the same ground from the beginning.c) Most ADC datasheets say to split the digital and analog planes and just connect under the ADC. Again, my supplies (3V3dig and 5Van) are created from the same input so they share the same ground from the beginning AND should I connect the planes under All 4 ADC? Just under one of them?Thanks, Mauricio Scaff
Lazyboy Calculator for gain and offset - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: March 04, 2022, 02:18:23 pm
content: So I was getting bored with calculating scale and offset for some sensors. So I made this little spreadsheet to calculate gain and offset to fit a given range. I hope its self explanatory.rescaler.xlsx(55.35 kB - downloaded 264 times.)
LBAD0ZZ1SE LTE-M (Cat M1) cell modem for IoT? - Page 1
Forum section: electronics / projects

author: Eric_the_EE
author_rank: Contributor
timestamp: November 18, 2022, 07:37:14 pm
content: Looking for a cell modem for my IoT application, and this one is relatively new but looks intriguing. Anyone have any experience using it? If so, what's the good, bad, and ugly?Type 1SE LBAD0ZZ1SEhttps://www.murata.com/en-us/products/connectivitymodule/lpwa/overview/lineup/type-1se
LC filter arrangement for brushed DC motor noise reduction - Page 1
Forum section: electronics / projects

author: keshab.patel
author_rank: Contributor
timestamp: March 18, 2017, 04:15:15 am
content: Hi everyone. In the attached a brushed motor's noise is reduced by typical LC filter. Could you please tell me why 22nF capacitor is used in parallel with the 10uH inductor. Is there any better solution to reduce the noise.

author: rs20
author_rank: Super Contributor
timestamp: March 18, 2017, 04:39:47 am
content: That's not atypicalLC filter -- in a normal LC filter, the L and C are arranged like a voltage divider, not sitting in parallel as you have them shown there. There might be some good reason for arranging Ls and Cs as you have shown in the diagram there, others will comment on that I'm sure, I'm just saying that it's not a typical LC filter.
LC-filter in ESP32-C3 - Page 1
Forum section: electronics / projects

author: okw
author_rank: Frequent Contributor
timestamp: October 24, 2024, 01:37:39 pm
content: I'm designing a custom ESP32-C3 board, and have questions about L1/C7 from the hardware design guidelines.According to the guidelines, L1 (2nH) and C7 (1uF) form a LC-filter to suppress high-frequencies on the power rail. That would mean a cut-off of 3.559MHz. Is this frequency determined by ESP? And why not cut-off even lower? Or have they determined the frequencies below this aren't harmful to the ESP32-C3?Next is, can these values be altered to give approximately the same cut-off (by lowering L and increasing C, or vice-versa), and give same result? Or does that affect something other (in a good or a bad way)?For example 1.5nH + 1.2uF (3.751MHz) of 3.9nH + 470nF (3.7174MHz).

author: temperance
author_rank: Super Contributor
timestamp: October 24, 2024, 01:47:12 pm
content: Except for the inductors in the antenna path those inductors are probably ferrite beads. The stuff some like to sprinkle around as if they are putting salt on a meal until it tastes good. Instead of improving stuff it is very easy to create an unwanted tuned circuit with those especially when combined with MLCC caps without any kind of damping in place.https://www.analog.com/en/resources/analog-dialogue/articles/ferrite-beads-demystified.htmlHow are you going to perform the antenna matching?
LC resonance and inductor ESR - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: January 12, 2018, 09:17:02 pm
content: When you calculate a RLC filter, you can pretty easily use a simulator to see if it resonates.Is using the R of the inductor as a lumped element R accurate, when determining how much resistance to add, or is it more complicated then that?I ask because of academic interest. I have trouble with distributed things.

author: danadak
author_rank: Super Contributor
timestamp: January 13, 2018, 02:14:54 am
content: Lumped models generally accurate for 99% of designs.Because the actual environment is distributed that would be the more accurateinsight into the properties. There are even mechanical effects due to magnetic fieldsaffecting spacial dimensions, therefore L and C values. But again the everydaydesigns we primarily deal with are minimal effects.Regards, Dana.

author: CopperCone
author_rank: Super Contributor
timestamp: January 13, 2018, 02:37:19 am
content: if you wanna write a thesis I will read it

author: danadak
author_rank: Super Contributor
timestamp: January 13, 2018, 12:48:22 pm
content: I have a TODO list and interests that exceeds my remaining lifetime, so will pass.Regards, Dana.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: January 13, 2018, 03:55:47 pm
content: For low frequency stuff, lumped models are fine. For RF, maybe not. Remember that lumped models are usually good for a single frequency only. Change the frequency and you have to change the model. It's a common error people make with simulations.
LC Slide ruler Calculators - Page 1
Forum section: electronics / projects

author: Jebnor
author_rank: Regular Contributor
timestamp: July 15, 2018, 02:19:59 pm
content: I remember back when I was a kid (30 years ago), Mr. Brimo my neighbour had an oscilloscope and some tools he let me borrow. One of the tools I borrowed was a Circular Slide Ruler for calculating LC and LCR circuit values. Does anyone have one They could take a picture of, or know of a place online where I could print one out? I love computers and all, But I like the visual representation of Slide rulers and the "ishyness" of them.I know I can make one, but I was just wondering if someone had one for easy reference.Thanks, Jeb.

author: bd139
author_rank: Super Contributor
timestamp: July 15, 2018, 06:31:37 pm
content: ARRL still sell new ones:http://www.arrl.org/shop/L-C-F-and-Single-Layer-Coil-Winding-Calculator

author: Fungus
author_rank: Super Contributor
timestamp: July 15, 2018, 08:53:36 pm
content: I'm a big slide rule fanboi.There's all sorts of special slide rules out there for electronics work:https://www.ebay.com/sch/i.html?_nkw=electronics+slide+ruleInfo:https://www.google.com/search?q=electronics+slide+rules