hybridfree/eevblog-posts huggingface dataset:
Best thermal performance needed - Page 1
Forum section: electronics / projects

author: CabanzoJ
author_rank: Newbie
timestamp: September 04, 2017, 11:30:29 pm
content: I'm building a project that needs good enclosure thermal dissipation, from the picture, what topology will be more effective.

author: Mr.B
author_rank: Unknown
timestamp: September 04, 2017, 11:55:35 pm
content: In my experience you would typically bring the air in over the cooler components, then pass it over the hotter ones to the exhaust.That is your options 2 and 3.Then you need to decide if the inside of the enclosure is better off slightly positive pressure (opt 2) or slightly negative pressure (opt 3).You may also need to consider how hot the exhaust air will be as you may not want that air passing through your fans as shown in option 3.

author: 2N3055
author_rank: Super Contributor
timestamp: September 05, 2017, 08:41:13 am
content: What Mr B said..One addition: slightly positive pressure and filters on input will go far to prevent/minimize accumulation of dust inside case...
Best use I've seen for a cheap 3D printer - Page 1
Forum section: electronics / projects

author: AndyC_772
author_rank: Super Contributor
timestamp: February 14, 2014, 07:16:33 pm
content: Never mind making crappy toys and other useless bits of malformed plastic... take a look at this project which uses a bunch of 3D printer parts, it looks like fun

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 14, 2014, 07:22:45 pm
content: That's just great!
Best way to cheaply measure AC current - Page 1
Forum section: electronics / projects

author: Dejan567
author_rank: Contributor
timestamp: May 14, 2024, 12:53:41 am
content: This is reference to my earlier post:https://www.eevblog.com/forum/projects/weird-coil-configuration-does-it-classify-as-parallel-lc-circuit/Please refer to this post and specifically Reply #24 for more information about the exact set up. I am looking to measure the current on either the input or output as accurately as possible without buying a super expensive current probe or wasting a lot of power. If having to choose, I would rather do the latter.The current probe I currently have is MicSig CP503B, which to my understanding can measure only 20 mA reliably. Again, I am working in kHz to low MHz range. Budget is, of course, limited.I am using a signal generator to drive my circuit. Now I know impedance matching is a significant issue here as well so looking for suggestions or to know if it's even possible (and how to do it, precisely). I was thinking of using a precise resistor in series and measure the voltage drop across it but again there is the impedance matching issue.Any suggestions? Please give as much detail as is possible.

author: moffy
author_rank: Super Contributor
timestamp: May 14, 2024, 01:41:01 am
content: This is a reference to an open source wideband current sensor, you probably just need the current transformer and amplifier not the Hall effect part:https://www.sciencedirect.com/science/article/pii/S2468067218300592

author: aliarifat794
author_rank: Regular Contributor
timestamp: May 14, 2024, 06:45:12 am
content: The cheapest that I can think of is ACS712. ACS712 is an AC or DC current sensor, which is used to measure AC or DC current. You should also have a look at Difference between AC & DC Power, that will help. The maximum value of AC and DC which can be measured is 30A, its output current signal can be read via analog I/O port of Arduino.https://www.theengineeringprojects.com/2019/03/introduction-to-acs712.htmlHere is how you can measure AC current with ACS712 and Arduino.https://microcontrollerslab.com/ac-current-measurement-acs712-arduino/
Best way to connect power pins - Page 1
Forum section: electronics / projects

author: c64
author_rank: Frequent Contributor
timestamp: July 16, 2020, 05:33:12 am
content: 4 layer board:layer 1 - signal layerlayer 2 - ground planelayer 3 - power plane (orange line is split between VCCINT and VCCIO)layer 4 - signal layerTQFP chip on top layer (layer 1), 0.5mm pitch.How to connect power pins? I see 3 options. I think option A is no good. Not sure which one is better - B or C. B has shorter traces than C. But C both VCC and GND go close to each other all the way to power planes.How would you connect power pins?
Best way to disconnect serial bus on a circuit. - Page 1
Forum section: electronics / projects

author: dralthi
author_rank: Contributor
timestamp: May 05, 2016, 03:26:08 pm
content: Hi folks, so here is my dilemma: I want to stop communication between two TTL logic chips on a mother board. The CPU 1 has a Serial out, Latch going to the CPU 2 as shown:_______ ________| CPU 1 |----------Clock--------------| CPU 2 || |-----------------Serial-------| || |----------Latch enable-------| ||______| |________|What would be the safest way to do this?a) Cut the clock trace?b) Cut the Serial trace?c) Cut the Latch enable?d) Connect the clock trace to Ground by a jumper? (this will short the clock to ground)e) Connect the Serial trace to Ground by a jumper? (this will short the Serial trace to ground)f) Connect the Latch enable to Ground by a jumper? (this will short the Latch trace to ground)I would appreciate any input from experienced guys out there before I damage the chips. I was planning on first cutting the Latch enable trace...and if that doesn't work, taking latch enable to ground?Thank you.

author: wraper
author_rank: Unknown
timestamp: May 05, 2016, 03:37:27 pm
content: Quote from: dralthi on May 05, 2016, 03:26:08 pmCertainly don't do those.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 05, 2016, 04:25:21 pm
content: Shorting any of the connections to ground or VDD is unwise to say the least.I would cut the latch trace, and solder a resistor from the trace that connects the latch to CPU2, to ground, if its active high. OR....to its IO voltage if its active low. That would just stop the input floating. As latching works on edges it probably wouldn't matter if its active high or low, but I suggested a resistor 'ground' because its probably the the most common connection on the board. If theres ground plane around the traces, then it wouldn't be too much hassle to scrape off the solder mask on the CPU2 side of the trace, and ground next to it, and put a 0603/0805 resistor (10k?) there.

author: dralthi
author_rank: Contributor
timestamp: May 05, 2016, 04:41:40 pm
content: Thanks, I'll give that a try.
Best way to drive four 5x7 displays... - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: January 08, 2016, 05:24:41 pm
content: Hi Everyone,I know there are a lot of ways you can do this. What I'm asking is, what is your least cost, least complication, least part count method.An AVR will control them so I've got good old fashion GPIO's to drive them. I don't mind multiplexing in an ISR, that is no big deal.Each LED (5x7x4=140 of them) needs to be able to support an average of 2mA for adequate brightness. I am planning on using a LTP-305 type display and it says you can do 10mA continuous or 75mA pulse with a 10% duty cycle.I plan to utilize SMD parts for the AVR/driver components, and I may even try to flatten out the leads on the displays to keep from having through hole. Nothing smaller than TQFP44/64 pitches (0.8mm preferred).I am ok with it taking up a number of pins on the AVR, but obviously less is better.You could drive it as a 7x20 or a 14x10.What would you do?

author: ajb
author_rank: Super Contributor
timestamp: January 08, 2016, 06:34:15 pm
content: Least cost (except it may require a larger MCU), lowest complication: 20 resistors for columns, 7 transistors for rows connected to 24 IO lines, gives a 1/7 duty cycle. Requires that the MCU pins sink 14mA to get an average current of 2mA. May be a pain to route.Lowest part count, fewest MCU pins: one or two 12/16 channel (depends on matrix arrangement) constant current LED drivers, plus 7-10 transistors for rows. Saves all of the column transistors, and if you have enough spare channels on the LED drivers, you can use them to drive the row transistors as well and use 2-5 GPIOs to control the entire matrix via SPI/I2C.Highest capability: As above, but use PWM-capable LED drivers, providing grayscale control over the matrix. Synchronization of the PWM periods to the matrix scan rate may be tricky.

author: alank2
author_rank: Super Contributor
timestamp: January 08, 2016, 06:46:48 pm
content: Quote from: ajb on January 08, 2016, 06:34:15 pmDo you have any example IC's.I know about the HT1632C (32x8 or 24x16) driver. It is a TQFP52 and needs only resistors. Maybe it is the best bet.

author: ajb
author_rank: Super Contributor
timestamp: January 08, 2016, 06:59:59 pm
content: Actually I was thinking of simple multi-channel constant current LED drivers, not matrix controllers. Possibly part count because you don't need any column resistors, and more flexible than many dedicated matrix ICs. Here's TI's page of >8 channel drivers, not all of them are constant current, though:http://www.ti.com/lsds/ti/power-management/signage-linear-products.page#p25=8;48I've used the TLC5940/59401, which requires a bit more interaction with the MCU to generate a grayscale clock and blanking signals, but that makes it a bit easier to sync with matrix multiplexing scan rate, and it does 12-bit PWM and per-channel dot correction.I know NXP have a few options as well, and certainly so will other manufacturers. There's also the WS2803, IIRC.
Best way to electronically trigger a Hall effect latch sensor ? - Page 1
Forum section: electronics / projects

author: guix
author_rank: Newbie
timestamp: May 27, 2024, 12:48:23 pm
content: Hello!I'm (still) working on a device that is a small test-bench for a moped's digital dashboard. It can test almost all functionalities of the dashboard. Almost allOn the front wheel of the moped, there is a multi-poles ring magnet, and a Hall effect latch sensor(A1220 datasheet), to calculate speed.Similar to this illustration :There is 16 pulses per revolution of the ring magnet, and let's say the top speed of the moped is 200 km/h (the dashboard's LCD display will show max 199 km/h). The wheel circumference is ~1800mm, and 200km/h = ~56 m/s, so at this speed, the wheel spins at 56 / 1.8 = ~31 revolutions per second, and the hall sensor is triggered on and off, at a frequency of 31 * 16 = ~500 Hz.So I would like to have a device that is able to generate a magnetic field that can be detected by the Hall sensor (which will be inside the test-bench enclosure), at a frequency between 0 and 500 Hz that can be set by an arduino program (which I can make).I don't want to get rid of the Hall sensorand simulate the speed directly by an arduino, because the purpose of the test-bench is to test the circuit of the dashboard : if the speed is not displayed on the LCD, then I know there is a faulty component on the PCB of the dashboard.Of course the first idea I have, is to "simply" replace the wheel of the moped, by a motor with a variable speed between 0 to 31+ revolutions per second (~2000 RPM), and attach a ring magnet with 16 pulses per revolution to it, and control the speed of the motor with the arduino.But I would prefer if it was silent, with no moving parts, and as small as possible. Is there a better way ? I've searched aboutusing a coil or electromagnetbut I'm not sure if it's applicable in my case.How would you do that, if you were me ?

author: themadhippy
author_rank: Super Contributor
timestamp: May 27, 2024, 01:03:08 pm
content: coil of wire driven by an H bridge,the H bridge reverses the polarity across the coil so the magnetic field polarity changes.

author: voltsandjolts
author_rank: Unknown
timestamp: May 27, 2024, 01:11:10 pm
content: Quote from: guix on May 27, 2024, 12:48:23 pmWell, you need to generate a magnetic field for your test bench, where the magnetic field strength is a little lower than the expected field strength the sensor will see in the application. You could do this by spinning one of your wheel magnets, at a spacing which is just slightly more than the application, to guarantee the sensor works with the minimum expected field strength. Or you could simulate that with a coil as per above suggestion - but make sure the field strength is comparable, or the test doesn't mean much. Using a coil would make it easier to test over a range of field strengths.
Best way to feed power into secondary boards? - Page 1
Forum section: electronics / projects

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: May 29, 2021, 11:23:42 am
content: Hi AllI am working on a multi-board design (hobby project) and am wanting to know, what is the best way to feed power into secondary boards? Like is it better to generate 3.3V locally or can I just feed it in via a filter?For example, I have two secondary boards (RECEIVER_SENSOR-RIGHT & RECEIVER_SENSOR-LEFT) that are connected to a primary board (RECEIVER_MAIN-BOARD). With the current design I want to generate 3.3V on the primary board and then feed it into the secondary boards via a pi-filter. Reason for this is that board space is tight so it’s easier to just feed in 3.3V rather than generating it locally

author: SeanB
author_rank: Super Contributor
timestamp: May 29, 2021, 02:08:15 pm
content: Short distances, so just feed 3V3 power in to the board. Remember those ceramic capacitors are very low inductance, so will ring with the inductance of the leads, so best to put a 4R7 SMD resistor in series with the power lead to provide damping. Will drop voltage slightly, but likely depending on current draw from the board you will be fine with 100mV of voltage drop. You do not even need the first capacitor, or the inductor, easy to replace it with the resistor, in place of L1 and delete C1. Will do a better job of decoupling, and also will provide hot plugging protection.

author: Siwastaja
author_rank: Super Contributor
timestamp: May 29, 2021, 02:41:54 pm
content: Filtering is hard, worth of PHDs and $100000 simulation tools, don't do it randomly in hobby projects for no reason.Proper local bypassing is important, though. In addition to the chip-side 100nF ceramics, a larger high-ESR bulk capacitor at each card is always a good idea. Any cheap electrolytic cap like 100µF does the trick. This provides the damping that was talked aboutwithoutthe massive 4.7ohm series resistance suggested above.Short runs low currents, just supply 3V3 as is. This is especially case with digital logic and IO voltages. Removes any power sequencing issues as well.Whenever something requires larger currents and/or good voltage regulation, higher bus voltage regulated down with local regulators is a good idea. For example, a small DC motor with 100s of mA stall current would be something I would not try to power from the 3V3 bus shared with microcontrollers. In such cases, pay attention to power sequencing conditions of ICs with multiple separate power pins. Similarly, make sure ICs don't get voltages in their IO pins before their IO power supply has stabilized, unless the devices are explicitly specified to allow such operation without latch-up or other issues.
Best way to get a single ended signal into a differential input amp? - Page 1
Forum section: electronics / projects

author: MatCat
author_rank: Frequent Contributor
timestamp: May 01, 2014, 11:48:20 pm
content: I am considering the MAX9788 (Datasheet:http://datasheets.maximintegrated.com/en/ds/MAX9788.pdf) to drive a piezo speaker, however it requires a differential output but my output will be single ended, do I need to use a special chip to convert (also requiring negative voltage), or can I just bias one of the differential inputs (wouldn't this attenuate the signal however?)?

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 02, 2014, 12:27:53 am
content: You could try simply grounding the unused input. But a quick glance at the block diagram suggests doing that will reduce the potential output level by 50% (3dB)There are many ways of generating a phase-inverted signal.What does the source circuit look like? Hard to suggest anything specific without seeing the larger picture.

author: MatCat
author_rank: Frequent Contributor
timestamp: May 02, 2014, 03:13:59 am
content: Quote from: Richard Crowley on May 02, 2014, 12:27:53 amThe audio source will be an STM32 utilizing it's own DAC, I have not finalized the audio setup yet because I haven't fully nailed down the final amp and speaker. This chip fits my needs really well for the speaker, I am just waiting on pieces to prototype it out.
best way to interface my racing sim lever to USB interface - Page 1
Forum section: electronics / projects

author: cmcraeslo
author_rank: Regular Contributor
timestamp: July 27, 2020, 02:23:24 pm
content: Hello guys.I have designed my own racing sim gear lever and i'm now in the process of finding the best way to interface it to the computer. I'll try to market that so i need a solution that will be easily available and very reliable (1000+ units)What way would be the best way to do it? I want to have some flexibility. Ideally, I want to have my STM32 as an interface for the switches (+ other inputs) and i'm looking for a chip that would allow me to easily interface the USB with the STM32 (like analog stuff, digital switches, etc).Looking at the FTDI, there are some HID chips available, but i'm not sure if this is what I need?I prefer FTDI, due to reliability and great driver support. Last thing I want to is to (potential) user to deal with the drivers.Which one would you recommend (think ofThanks

author: Renate
author_rank: Super Contributor
timestamp: July 27, 2020, 05:18:42 pm
content: You definitely want to use a single microcontroller with built-in full or high speed USB.Me? I'd use an AtMega32u4. Why? Because I know them well and I could knock out the code in an hour.You? Well, you have a wider choice of microcontrollers. An STM32 with USB is fine.This will be (should be) and HID device.All systems support HID devices without further drivers.No need to mix any FTDI in.

author: robca
author_rank: Frequent Contributor
timestamp: July 27, 2020, 08:25:40 pm
content: Quote from: cmcraeslo on July 27, 2020, 02:23:24 pmMost STM32 (e.g. even the lowly STM32F103) have USB built in. Look at all the cheap Blue Pill boards, they all have just the STM32F103 and LDO on board.Why would you want to use more chips when the "right"STM32 does everything you need? What am I missing?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 27, 2020, 08:28:55 pm
content: https://github.com/FreeJoy-Team/FreeJoy

author: cmcraeslo
author_rank: Regular Contributor
timestamp: July 28, 2020, 05:31:24 am
content: You guys are correct, I apologize. I automatically thought that I need special drivers for HID controls and it made me remember by days with the non FTDI devices and drivers. Looks like only STM32 will do a perfect job. Thanks.

author: Renate
author_rank: Super Contributor
timestamp: July 28, 2020, 01:19:28 pm
content: Quote from: cmcraeslo on July 28, 2020, 05:31:24 amWoah, no need for that!We're just here talking about stuff and everybody was polite.
Best way to protect product from shorts through ground connections. - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: August 13, 2023, 03:27:22 am
content: I have a charger, it has 4 wires, input and output, and the 2 ground just connects straight through.It's fully protected from reverse polarity on input and output in terms of my circuit. However there's also the risks created by the common ground.If the input side, or output side, wires get inverted and there's a ground loop somewhere it becomes a dead short through the ground link inside my device.Obviously one option to fix this is just make my charger fully isolated.But I don't want to do that.Another option is a fuse or poly fuse.Another option is to make the charger only 3 wire and only have 1 ground.I'm tempted to do this. But it means my ground path 'takes the scenic route' and runs god knows where to get to ground for either the input or output path. Note that it's a charger so there's the ground of the source and the ground of the battery being charged. Not really a common ground point.Are there any other options to solve this sort of issue?
Best way to test HID ProProx Reader w/o System? - Page 1
Forum section: electronics / projects

author: joshforester
author_rank: Contributor
timestamp: April 15, 2017, 04:59:34 am
content: I have a HID ProProx 5355AGK unit that I need to test before I can sell it, but just putting 12VDC through the thing did nothing. Any of you guys have any idea how I can test this, without having it tied to a full system?Pictures of unit & sticker attached.Thanks!

author: 2N3055
author_rank: Super Contributor
timestamp: April 15, 2017, 07:56:07 am
content: That thing works with a Wiegand protocol.Two data lines, one for zeros, one for ones..Hookup power, connect two channel scope to DATA0/DATA1 and bring the card close.. If it works, it will read the card and send a burst of impulses on on both outputs..That is not comprehensive test, but if that works it is very probable it is OK..To be really sure, you would need to connect it to something that would decode full protocol and show you card data...
Best way to use a photodiode digitally? - Page 1
Forum section: electronics / projects

author: cubemike99
author_rank: Contributor
timestamp: January 31, 2014, 11:14:13 pm
content: I'm trying to make my own PC interface cable for my multimeter, which sends data out through IR without a carrier. Since I haven't been able to find a 3 pin IR receiver that isn't designed for use without a carrier, I'm using an IR photodiode. The "reverse bias" method hasn't been working very well. I've seen many circuits labeled as photodiode amps, but I'm assuming that these are made for getting analog values.What method can I use to get a buffered (if I'm using the word correctly), digital output from an IR photodiode?

author: dannyf
author_rank: Super Contributor
timestamp: January 31, 2014, 11:21:38 pm
content: Put it to a mcu that communicates to a master.

author: Bassman59
author_rank: Super Contributor
timestamp: January 31, 2014, 11:21:46 pm
content: Quote from: cubemike99 on January 31, 2014, 11:14:13 pmSeeherefor example.Use an op-amp or a transistor to buffer the photodiode output, then use a comparator to turn it into a logic signal.-a

author: plesa
author_rank: Frequent Contributor
timestamp: January 31, 2014, 11:28:10 pm
content: http://omapalvelin.homedns.org/fluke/

author: VK3DRB
author_rank: Super Contributor
timestamp: February 01, 2014, 12:32:31 am
content: Use a simple transimpedance amplifier circuit using an op-amp. This amplifies the tiny current from the photodiode to a usable voltage to drive a transistor. From the output of the op-amp, drive an n-channel MOSFET or an NPN transistor as a switch, and there is your digital signal.Select the value of the op-amp feedback resistor reasonably carefully. This controls the gain. Too much gain means you will amplify background light as well as the real light signal, turning on the transistor all the time. Too little gain means the transistor won't turn on.Check the output of the op-amp. Reason is you will want to verify you have selected the right feedback resistor value.If you use high speed pulse width modulated light onto a photodiode, you can filter the PWM using an RC filter.

author: cubemike99
author_rank: Contributor
timestamp: February 07, 2014, 09:47:30 pm
content: Thank you for all of your help. Below is what ended up working for me. The op amp I used was a LM324. The mosfet is an IRF 644. That wire on the right is output.

author: dannyf
author_rank: Super Contributor
timestamp: February 07, 2014, 10:14:08 pm
content: QuoteNone of that is "digital".

author: cubemike99
author_rank: Contributor
timestamp: February 08, 2014, 07:13:39 pm
content: Quote from: dannyf on February 07, 2014, 10:14:08 pmYes, it is. The output wire on the right is 0/5V. Here's the rest of the circuit.
Best Websites for Circuit and PCB Design News and Advice - Page 1
Forum section: electronics / projects

author: aw_rw1
author_rank: Contributor
timestamp: January 04, 2023, 07:25:58 pm
content: I don't have too many sites to go to for circuit or PCB design. For circuit design, go on Google or this forum. For PCB design, I just go to David's PCB Design Tutorial. I got some theory down from university, but for review I go to Google, textbooks or Electronics Tutorials. Sadly, I don't have a place to go for news. Maybe I'd see something new on my YouTube feed. I kind-of started going to this forum for news.How about your places for this? What's the best websites for circuit and PCB news and advice?

author: bidrohini
author_rank: Regular Contributor
timestamp: January 07, 2023, 07:52:21 am
content: Here is a list. You can visit all the mentioned websites:https://blog.feedspot.com/pcb_blogs/
best/worst practice on reverse engineering a circuit/gear - Page 1
Forum section: electronics / projects

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 08, 2022, 06:40:42 am
content: i have been repairing vintage gear and reverse engineering is one of my hobby/past time. (well.. a schematic/service manual helps) but why take the fun out of repairing your own gear?is there a tool that automates this?or the sheer collective engineers on forum is better?

author: jwet
author_rank: Frequent Contributor
timestamp: January 10, 2022, 03:29:09 am
content: There is great British YouTuber named BIGCLIVEDOTCOM that does a lot of reverse engineering of PCB type gear, might be applicable to some of your work and might give you some ideas even on the real vintage stuff. He takes high resolution pictures, reverses them with PC software, prints them out and uses transparency foil stock, makers, etc to make the process easier. Worth a watch.In my experience, I go through with a continuity beeper/DMM and draw the circuit as I go. I then try to redraw the circuit a couple of times until it makes sense. Usually, the first stab makes everything look complicated and upside down- like a bad schematic. After you revise it a couple of times, you'll recognize structures and the flow of the circuit. Bypassing and similar circuits can make for head scratchers. I try to follow the real signal stuff and do the supply rails and don't worry if its not all perfect. If you can power it up safely, you can refine your schematic with DC bias levels, etc. and chase out the bypass and bias circuits.Good luck.
Better alternative to the PAM2863 LED driver? - Page 1
Forum section: electronics / projects

author: GhostDog
author_rank: Newbie
timestamp: January 24, 2023, 11:55:05 am
content: I'm designing a circuit that requires a microcontroller to control 4 LEDs, each with a peak current of 500ma max. Currently, my design is using the PAM2863 LED driver (https://www.diodes.com/assets/Datasheets/PAM2863.pdf), but I'm not a fan of the quite large inductor this requires (having an inductor that is nearly 1/3 my board's total size). Could anyone suggest alternatives?Things I'm looking for:Ability to be controlled on a 3v3 logic pin from a microAbility to take roughly 2 ampsSMD package that's at most SOIC-8 sizeThings that would be nice:Ability to control current limiting through a microcontroller pinNot many large external components (looking at you, inductor)Cheers - GhostDog

author: mariush
author_rank: Super Contributor
timestamp: January 24, 2023, 01:44:51 pm
content: The driver already works at up to 1 mhzYou don't say the forward voltage of the leds, just the current... you don't say the input voltage ... only assume from the previous driver that it's a step-down regulatorIt's 2-3x more expensive but have a look at something likeMP4425AGQB-Z 4-36v in, 1.5a, 2.2 Mhz :https://www.digikey.com/en/products/detail/monolithic-power-systems-inc/MP4425AGQB-Z/13882239Maybe ILD8150 if you want SOIC, but beware it's minimum 8v, max 80v , 1.5A , 2 mhz ... dimmable brightness 12.5% ... 100% and i'd also be a bit concerned about availability in the futureILD8150https://www.digikey.com/en/products/detail/infineon-technologies/ILD8150XUMA1/11500212
Better cheaper EMC probes from EEVBlog #1178 - Page 1
Forum section: electronics / projects

author: ScottBLAM
author_rank: Contributor
timestamp: February 08, 2019, 02:28:48 am
content: I saw the video and thought conductive tape foil would work better because you are working with signals around a flat plane the build isn't much harder. Stick the foil to a surface, cutting the foil into shape, add a layer of insulation tape and then add the shielding tape to overlap the edges of the insulation layer. Then add another layer. Maybe adding some compression between a few steps could help to shave off the millimeters but it runs the risk of ripping the materials. Both copper and gold foil tapes are available and gold foil tape would improve sensitivity with out much cost.Some cooking utensils have a nice silicone thermal resistant and electrically insulated material that people may want to chop up into strips to finish off their probes in case they touch their probe to something hot or high voltage.https://youtu.be/2xy3Hm1_ZqI

author: EEVblog
author_rank: Unknown
timestamp: February 08, 2019, 02:47:31 am
content: Welcome to the forum.I can't see how this is going to beat a a $3 delivered terminated coax on ebay?

author: ScottBLAM
author_rank: Contributor
timestamp: February 08, 2019, 03:11:53 am
content: I guess it doesn't. It just depends on what you have on hand.

author: cdev
author_rank: Super Contributor
timestamp: February 08, 2019, 03:42:34 am
content: Dave,Thank you!
Better Eagle import script - Page 1
Forum section: electronics / projects

author: Joshua
author_rank: Regular Contributor
timestamp: January 21, 2014, 12:14:29 am
content: Hey everybody,So it occurred to me that the reason why my gerbers were taking so long to generate in Eagle, is because I have multiple logos on the board. In case you are not familiar with eagle's import bmp script, my understanding is it makes a bunch of tiny rectangles. Each rectangle has a height of 1 pixel and length x pixels, where x is the number of pixels in a row of the same color. It can do fancy things like scaling and whatnot, but this is the general idea. Anyway, for a large resolution logo (I know, I know, you can use a bmp with less pixels), there can be hundreds and hundreds of little rectangles. Why not make these rectangles less?Here's my idea, commonly referred to as the maximal rectangle problem. Here is a good link on the subject.http://www.drdobbs.com/database/the-maximal-rectangle-problem/184410529So, why not find the largest rectangle, and create it. Then subtract this rectangle from the image, and start again. This way, you have the minimum number of rectangles possible. Has anyone ever tried this? Is there any reason why it shouldn't work?Joshua
Better surface mount layout question - Page 1
Forum section: electronics / projects

author: mribble
author_rank: Regular Contributor
timestamp: August 24, 2011, 10:32:26 am
content: I'm having low success rates soldering the a SON-10 package with my boost converter on it. Part here:http://ca.mouser.com/ProductDetail/Texas-Instruments/TPS61200DRCR/?qs=sGAEpiMZZMtY9G8Xaw%2fcnvufCtuHXcIeHere is my current pcb layout:I noticed sparkfun uses a similar chip with a different layout. There part is here:http://www.sparkfun.com/products/10300The problem I've having is that the ground plane shorts to some of the pins. I know adjusting the stencil mask might solve this problem, but I'm wondering if the design by sparkfun has advantages.Does having ground planes on the top and bottom help prevent board flex during soldering? Also do those 3 vias under the chip help prevent solder overflow?In general do people see advantages or disadvantages to the layout used by sparkfun?

author: daedalus
author_rank: Regular Contributor
timestamp: August 24, 2011, 11:59:57 am
content: Is there some reason you are not following the manufacturers recommended footprint for this part? They have a recommendation for thermal vias and solder paste coverage that you seem to be ignoring.The vias are there primarily to conduct heat to the ground plane on the bottom of the board. If they are not capped (i dont use eagle, so am not sure), then they will end up wicking some solder paste through when the part is mounted, but this is more of a side effect.The problem you are having is most likely that you are applying too much solder paste on the central pad. Having a single aperture for this is problematic, you might be better off splitting this into several smaller apertures, and going for a lower fill ratio. The manufacturer recommends a fill ratio of 72%, but you will probably be ok down to 50%. The lower the fill, the less chance of shorts.

author: mribble
author_rank: Regular Contributor
timestamp: August 25, 2011, 12:23:10 pm
content: Daedalus,I haven't used parts where stencil coverage mattered in the past so I kind of glazed over that part of the data sheet while reading it. I am now taking a very close look at their recommendations in this area and taking them into account with the stencil mask. Thanks!

author: KashmirGR
author_rank: Newbie
timestamp: August 31, 2011, 05:35:21 pm
content: For best results:- Pad dimensions should follow pin dimension + 0.25-0.75mm toe- Soldermask between pads (1:1 with pad, PCB vendor to open. Do not gang relieve).- Solderpaste should be 1:1 with pad, but can be slightly smaller (If you are going to do smaller, use less Y, and leave X 1:1).- Solderpaste for exposed pad should be 1:1, with 0.25mm cross pattern (4 solder regions) if pad is greater than 4mmx4mm- No PTH in pad, microvia okay.- For exposed pad, if you are using PTH via, cap on opposite side. It is better if you can keep these around the edge and seperate with soldermask from the soldered pad areaGenerally speaking, manufacturer recommended footprints will follow the above guidelines.
Better than a BU-353-S4 USB GPS? - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: August 01, 2021, 05:46:44 pm
content: I've had a BU-353-S4 USB GPS "hockey puck" running 24/7 and I really don't have any complaints.Still, it only receives L1 (and not L2?) and Glonass, Galileo & BeiDou remain foreign words.Am I missing out on anything as far as availibility and accuracy goes?Since it's 24/7 anyway, capture is not a biggie.Glonass & BeiDou don't sound very accurate.Are L2 and/or Galileo worth it?
Better ways to connect display modules... - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: September 06, 2017, 02:41:35 am
content: So take a module like this with the classic four mounting holes:I've used socket head screws with spacers along with a nylon flat washer and nut to fasten this to a pcb, but what other ideas are there?Why they don't make these things with some PTH's on the other side so one can simply use header to attach them, I don't understand. I wonder if there is a way you could solder some PTH header to the mounting holes on the opposite site, but that would probably not look good. Then again I haven't tried it to see what it would look like.I then saw that they make threaded spacers that look like they are designed for surface mount use like these:https://www.digikey.com/products/en/hardware-fasteners-accessories/board-spacers-standoffs/582?k=threaded+spacer&k=&pkeyword=threaded+spacer&pv5=6065&FV=1a380001%2Cffe00246&mnonly=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=100Any other thoughts or ideas, or is this it?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 06, 2017, 02:45:10 am
content: http://www.essentracomponents.com/en-gb/pcb-electronics-hardware/supports/adhesive-base-supports/adhesive-base-support-snap-locking-low-profile
BEWARE Counterfeit/FAKE DS18B20 1-wire temperature sensors - Page 1
Forum section: electronics / projects

author: member_xyz
author_rank: Contributor
timestamp: November 19, 2019, 09:16:23 pm
content: Source not verifieddeletedModerators, please delete this topic.

author: magic
author_rank: Super Contributor
timestamp: November 20, 2019, 11:58:13 am
content: Yes, functional clones of those ICs exist, with subpar performance. I have a few. There are even two different kinds of those fakes out there, and that's not counting transistors and other junk sold as DS18B20.
Beware eBay fuses/ fuse holders - Page 1
Forum section: electronics / projects

author: DonnieBrodan
author_rank: Contributor
timestamp: January 05, 2021, 06:57:51 am
content: I blew up an ESP32 Devboard connected to a 12v PSU recently, just got a new ESP32 in the mail, went to test it and no power. Went to check the inline fuse that I installed... Well isn't this interesting...You can see the case for the fuse is all warped. Might think that a fuse labelled F1AL250V would blow before warping the plastic? Unsure if the fuse did actually blow, as when I went to pull the fuse out, it shattered into many pieces.Edit: should have been a 200mA fuse, thats likely what caused this

author: mikerj
author_rank: Super Contributor
timestamp: January 05, 2021, 08:26:21 am
content: I suspect the problem is you don't have enough cable splices, I can see runs of almost an inch of plain wire without a spliceThe fuse holder almost certainly melted due to a bad contact to the end of the fuse causing the heating. Most of of these junky connectors and fuse holders use inappropriate metal and/or plated finishes that oxidise and cause poor connections.

author: CJay
author_rank: Super Contributor
timestamp: January 05, 2021, 10:52:13 am
content: Quote from: mikerj on January 05, 2021, 08:26:21 amYou can get a surprising amount of heat out of a fuse being run at or close to its rating, used to amuse me when I was repairing audio power amps to watch them on full output test into a load bank because some of them had fuses which would glow orange and sag in time with bass beats.
beware of lt6943 charge pump divider circuits (SLOOOOOOOOOOOOOOOW) - Page 1
Forum section: electronics / projects

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 31, 2014, 02:50:27 am
content: So I built this nice charge pump to divide my voltage reference... the only problem is... its soooooo bloody slow. it seriously takes like 5 min to get to the proper value... this was a hard problem to predict.I am not sure what to do now, I thoought it was a golden bullet for divider voltage references through out a system. I guess I need to replace it with a chopper amplifier + thermally matched resistorsperhaps I can include a comparator to switch this on while the user waits..

author: c4757p
author_rank: Super Contributor
timestamp: August 31, 2014, 03:05:08 am
content: Quote from: SArepairman on August 31, 2014, 02:50:27 amFiveminutes? Uh - how are you using it, and how close do you expect it to get?

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 31, 2014, 03:09:23 am
content: I am using it in a divide by four (2x divide by two)made with 4x high quality polypropylene 1uF capacitors + 10nF switching PP Cap (vishay type 63V signal grade)I feed it 4, it got to 0.8 in like.. 9 minutesslow as molasses going up hillgoing into a LTC1151 chopper amplifier (15pA bias current )10V supply on the lt6943not to mention its over counting, 1.2 v in a div x4 circuiti hope that something is wrong?

author: rs20
author_rank: Super Contributor
timestamp: August 31, 2014, 04:01:04 am
content: Maybe other people are smarter than me, but I need to see a schematic to have any confident opinion on this. Is the 10nF switch cap the one that's alternately being connected to one side of the lt6943 and then the other? Because 10nF is 100,000 times smaller than 1uF, even in an ideal world it's going to take hundreds of thousands of cycles before it approaches equilibrium. Any reason not to use a bigger switched cap?

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 31, 2014, 04:40:01 am
content: a ha. it was a floating pin.I forgot a trace going from the output of the first divider into the bottom side switch.(7 to 11 was DC)It had me fooled because it kinda almost worked...now its speedy and it works great!the only thing that was missing from the circuit was a piece of kynar wire!

author: c4757p
author_rank: Super Contributor
timestamp: August 31, 2014, 04:41:44 am
content: Quote from: SArepairman on August 31, 2014, 04:40:01 amDammit!I suspected as such, but was unsure and didn't want to talk out of my ass.

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 31, 2014, 04:43:00 am
content: it was kind of a pita to bodge that wire in, because its a tiny smd chip surrounded by massive (slightly molten ) capacitors.if i ever use one of these again I am going to surround it with the capacitors like a castle wall and put some decals and king arthur on the rampart
BEWARE of PCB prototype breadboards - Page 1
Forum section: electronics / projects

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 08, 2017, 06:35:56 pm
content: I use predrilled PCB breadboards extensively for most of my prototypes.But today I spent two hours solving a weird problem with a design that wouldn't work, with mosfets burning over and over again and strange signals on the scope.Well eventually I traced the problem to the PCB itself as it a had a copper trace in between two pads!That may explain other past prototyping problems. From now on I will inspect the boards before use, beware!Note trace in the middle of the photo

author: Kjelt
author_rank: Super Contributor
timestamp: July 08, 2017, 06:38:55 pm
content: And the left lower corner two more, what was the brand? Never had issues with the german made boards i always used.

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 08, 2017, 06:43:30 pm
content: Quote from: Kjelt on July 08, 2017, 06:38:55 pmThe lower left is a scratch... german made, which ones??These are chinese available all over epay. I use like 4-5 boards a month and from now on I will clearly pay more attention to this issue.

author: cdev
author_rank: Super Contributor
timestamp: July 08, 2017, 08:32:20 pm
content: Is its the two pads with the really tiny white line between them?

author: MarkS
author_rank: Unknown
timestamp: July 08, 2017, 10:40:57 pm
content: I must be blind! Can you point out the trace?

author: Kjelt
author_rank: Super Contributor
timestamp: July 08, 2017, 11:32:18 pm
content: Quote from: MasterTech on July 08, 2017, 06:43:30 pmRoth ElektronikAvailable from Farnell

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 09, 2017, 05:35:30 am
content: Quote from: MarkS on July 08, 2017, 10:40:57 pmCropped,

author: Dubbie
author_rank: Unknown
timestamp: July 09, 2017, 06:20:15 am
content: I had the exact same thing happen with the same boards.Kept blowing up components for no apparent reason. I kept checking my sums, but it ended up being a little bridge like this.
beware this web page - Page 1
Forum section: electronics / projects

author: k8943
author_rank: Regular Contributor
timestamp: April 09, 2019, 03:36:51 pm
content: https://hubpages.com/technology/USB-wiring-and-color-codeIt's quite convincing.Just cost me a couple of hours.

author: Gyro
author_rank: Super Contributor
timestamp: April 09, 2019, 06:11:15 pm
content: It would be better if you qualified what to beware of on the page, in your thread title too (clickbait).If the data is inaccurate, then you ought to clarify what. On the other hand, if it's infested with something harmful, then you shouldn't directly link it.Needless to say, I won't be clicking on the link.

author: Miti
author_rank: Super Contributor
timestamp: April 09, 2019, 06:57:37 pm
content: I clicked on that page but I have no idea what to beware of.

author: Nusa
author_rank: Super Contributor
timestamp: April 09, 2019, 08:24:52 pm
content: Quote from: k8943 on April 09, 2019, 03:36:51 pmThe article is an attempt to be literate about something he doesn't actually understand, but I don't see any attempt to deceive.The correct answer is to personally confirm what pin is associated with what wire color, and not to make any assumptions. To do that, you also need to know the actual pin-out of the USB plug/jack in question, which the article does not address at all.

author: amyk
author_rank: Super Contributor
timestamp: April 10, 2019, 01:31:02 am
content: Quoteseeing sentences like that is enough to give me the "be wary of this advice" feeling.There is no standard USB color code (and even if there was, do you think the Chinese care about something that literally won't be seen by anyone who isn't hacking open USB cables...?)

author: Miti
author_rank: Super Contributor
timestamp: April 10, 2019, 02:28:30 am
content: Aha, I saw that it is a bunch of crap spread over two pages but I didn't read it all and I didn't understand what to beware of.Maybe he can explain the S-Video cable as well?
Bezel / Slim Enclosure Suit 3.2" TFT Module ? - Page 1
Forum section: electronics / projects

author: David_AVD
author_rank: Super Contributor
timestamp: February 03, 2013, 08:13:41 am
content: I'd like to manufacture some control panels (~ 40 units) that use a 3.2" touch screen module such asthis onefrom SainSmart.I intend to make a custom piggyback board (that the LCD plugs onto) which has a micro, RS485 comms, etc on it. That's all fine and dandy.The end application would be in a home or office environment, so I'm looking for an attractive front panel or wall mount enclosure that would suit.Has anyone come across something like this?

author: Bored@Work
author_rank: Super Contributor
timestamp: February 03, 2013, 08:28:26 am
content: There is no shortage of such enclosures. Random pickhttp://www.teko.it/en/prodotti/famiglia/HH/serie/132

author: David_AVD
author_rank: Super Contributor
timestamp: February 03, 2013, 08:31:35 am
content: Thanks for that. My Google powers must suck today.Did you search Google in general or have the manufacturer known already?

author: Bored@Work
author_rank: Super Contributor
timestamp: February 03, 2013, 08:46:31 am
content: Already known. That that manufacturer is busy in Europe since decades.For other manufacturers, Dave's neglected Wiki has a listhttp://www.eevblog.com/wiki/index.php?title=Enclosure_Manufacturers

author: David_AVD
author_rank: Super Contributor
timestamp: February 03, 2013, 09:04:20 am
content: Ah, of course. I was thinking too much about the LCD. A more general search for plastic wall enclosures opens up many more possibilities.
BG7TB gpsdo NEO-8 dump requested - Page 1
Forum section: electronics / projects

author: erikka
author_rank: Regular Contributor
timestamp: December 17, 2023, 02:35:24 pm
content: The NEO-8 gps module of a BG7TBL died. It is possible to replace the module but I'm not sure about the settingsCan someone with a BG7TBL gpsdo provide a dump of the NEO-8 GPS module using the U-blox Tools => GNSS configuration dump command?

author: Aiy
author_rank: Regular Contributor
timestamp: December 19, 2023, 08:38:45 pm
content: Hi there,I ran into trouble with my BG7TBL GPSDO a while back.It might still work if you "patch" it a little bit, it might be worth a try.The CPU on the board programs the GPS module on boot. In my case, the GPS had a strange bootup RS232 baud rate which could be fixed by a resistor pull-up on one of the pins on the GPS.Check here what I did:https://www.eevblog.com/forum/projects/ublox-based-gpsdo-peculiar-baudrate-problemBest regards

author: erikka
author_rank: Regular Contributor
timestamp: December 19, 2023, 09:14:41 pm
content: Thanks, will be triedDo you also mean to say the CPU programs the settings of the gps so no need to pre program a replacement gps module?

author: erikka
author_rank: Regular Contributor
timestamp: December 20, 2023, 08:44:41 pm
content: The problem is solved with the added resistor. Thanks for the help