hybridfree/eevblog-posts huggingface dataset:
Designing a digital input - Page 1
Forum section: electronics / beginners

author: permal
author_rank: Regular Contributor
timestamp: May 07, 2017, 05:48:43 pm
content: This question is a continuation of myearlier question.In an attempt to learn more about designing a digital input for both AC and DC, I've come up with the attached schematic. My intention is to make the inputactive highand haveshorter rise and fall timescompared to those seen in theschematicin the linked question. The input in questions will be connected to anESP32.As per the previous question, the purpose of the polarized capacitor is to even out the on/off switching of U1 when AC is applied.I'm wondering if this is a viable way to design an input? The rise and fall times becomes rather long (11ms rise/47ms fall to reach required voltage levels) when I try to limit the current draw while the input is active. I'm concerned that during the time the voltage level is between what is considered low and high might cause erroneous reading on the uC. Of course, the fall time mustn't become shorter than the fall/rise of the applied AC for it to have any actual effect so it all must be balanced out.Would it be possible to reduce the rise/fall times to the uC by the use of an opamp? I know very little of them, but I seem to remember that they can be used to create a nice looking square wave from an analog signal?Any insights are welcome, but may I please ask you to be verbose in your comments so that I can understand the reasoning behind your answer?Thank you!

author: danadak
author_rank: Super Contributor
timestamp: May 08, 2017, 01:13:23 am
content: If you look at datasheet test ckt for Tr and Tf it grounds the emitter,places R in collector, takes output at collector. For 100 ohms resultsseems to be 5 uS for either transition. This would also eliminate needfor electrolytic. Electrolytic is giving you the very slow rise and fall times.Note this configuration logically inverts vs yours is non inverting.Regards,

author: permal
author_rank: Regular Contributor
timestamp: May 08, 2017, 05:39:15 pm
content: Quote from: danadak on May 08, 2017, 01:13:23 amPerhaps I wasn't clear in my initial post, but that is the very thing I want to avoid for this thought experiment.Is it possible to have a non-inverting input with acceptable rise/fall times towards the uC? If so, how?

author: danadak
author_rank: Super Contributor
timestamp: May 08, 2017, 10:37:36 pm
content: One alternative is to config UC inputs as Schmidt, essentially eliminatingany concern for rise/fall time. Or use a comparator with hysteresis.Regards, Dana.
Designing a Doctor Who version of "operation"  - Page 1
Forum section: electronics / beginners

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: February 07, 2014, 04:45:29 am
content: I am designing a Doctor Who version of "operation" and I would like to have it play a few different sounds (eg: cloister bell, tardis sound, sonic screwdriver sound, ect,) I would like to do this with an atmel MCU as that is the only kind I have experience with so far. The reason I want to use an MCU to make the sounds is because I am going to use one in the project anyway as I want an LCD(blue back light of course) with timers, scores, ect,. As an aside if any one has suggestions for the things you remove please leave them below.So far I have : sword fight hand, second hand, eye of harmony and a memory bug thing from the snowman invasion.

author: pickle9000
author_rank: Super Contributor
timestamp: February 07, 2014, 05:03:25 am
content: search for this:WTV020-SD-16P

author: ivan747
author_rank: Super Contributor
timestamp: February 09, 2014, 09:48:53 pm
content: This is ideal. It's called the MP3 trigger. You connect buttons, switches or whatever to its 18 inputs and depending on which input you trigger, it will play a corresponding audio file from a micro SD card:https://www.sparkfun.com/products/11029It's pretty much made for this same application, it's very easy to use and comes with almost everything you need. It's US $50 though.If this is a one-of project, that shouldn't be a problem. As a whovian, I'd like to see the finished Doctor Who gameQuoteCheck this part, this way you can integrate it to your score display board:QuoteNo, I don't work for SparkfunAs for the game, you absolutely need dual hearts, a sonic screwdriver, a weeping angel maybe...I should catch up with the series. I left just before the anniversary special.

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: February 11, 2014, 01:55:19 pm
content: i will post pics and/or video here after it is complete.
Designing a High Current Multi-Channel LED Controller with Trigger Capability - Page 1
Forum section: electronics / beginners

author: kandrey89
author_rank: Contributor
timestamp: July 03, 2016, 09:47:03 pm
content: Hi,I am looking to see how it's possible to design a multichannel LED Controller.Specs:3-4 Independent LED ChannelsLED Voltage: up to 24V (up 12V is OK, up to ~48V better)LED Current (DC): up to 1A (up to 3A better)LED Step Size: 1mA (0.1mA better)Trigger: External TTL trigger, fast LEDon rise/fall timePSU: Off the shelf AC-DC brick converter, could be 12/24/36/48VDC.Additionally, would very much like to have:photodiode stabilized LED current - a photodiode senses part of the light and adjusts the LED current to compensate, to keep LED luminosity within +-0.1%, have not researched what kinds of photodiodes would be useful, but obviously high dynamic range is a strong requirement, would prefer a very flexible setup to mount the photodiode wherever I want and be able to use different light levels.I was looking at this:http://datasheets.maximintegrated.com/en/ds/MAX16826.pdfBut I'm not sure I understand how it works with PWM.Some questions:Will the LED current/voltage be purely DC or will it be PWMed like a very fast on/off LED.Am I correct in understanding that I cannot use the PWM input signal to trigger an LED pulse, for example I send in a 200us TTL pulse, the LED flashes once for 200us.Could I use another power mosfet switch to disconnect the LED from the power mosfet (controlled by MAXIM) to accomplish triggered operation? Wouldn't that screw up the current regulation by shooting the voltage up to increase current?What's the proper way to design something like the specs I provided? Please link to any useful docs.My ideal goal would be to design and build a computer and manual controlled LED controller capable of driving 3-4 separate and individual channel LEDs at the same time up to 48V and 3A with 0.1mA resolution, external/internal pulse trigger, forward voltage monitoring, photodiode light stabilization, low current ripple, high accuracy and reproducibility. It could even be an open hardware project.
Designing a PCB using USB-C - Page 1
Forum section: electronics / beginners

author: AdamHer
author_rank: Newbie
timestamp: May 31, 2025, 03:31:16 pm
content: I am designing a PCB that will have a USB-C plug on it so I can grab the 5V and convert to 3.3V and power the rest of the board. Has anyone used a USB-C plug for a very basic design? Am I missing anything? Any tips?Anything helps! Thank you for your guys' time!

author: gamalot
author_rank: Super Contributor
timestamp: May 31, 2025, 03:38:21 pm
content: For your application, a low pin count Type-C connector may be a better choice, with the benefits of lower price, simpler PCB design, and easier soldering.

author: AdamHer
author_rank: Newbie
timestamp: May 31, 2025, 03:55:09 pm
content: I couldnt find a lower pinout PLUG that fits my needs. Also, if I can get this 24 pin figured out then i can use it for more advanced projects.

author: fourfathom
author_rank: Super Contributor
timestamp: May 31, 2025, 04:45:52 pm
content: Your connector pinout and connections matches what I am doing on a project. I use the USB data pins as well, but my design also operates when just connected to a USB charger. The full-pinout connector was pretty easy to use (I build my own KiCad library components and footprints).

author: gamalot
author_rank: Super Contributor
timestamp: June 01, 2025, 08:22:03 am
content: Quote from: AdamHer on May 31, 2025, 03:55:09 pmThis has absolutely nothing to do with the plug.

author: Eraldo
author_rank: Regular Contributor
timestamp: June 03, 2025, 08:03:28 pm
content: If you're going to handsolder, then definitely go for the 6 pin version, which only has the 2 cc pins and supply (no data). best one for simple projects like this.Also there is no problem with compatibility.

author: Whales
author_rank: Super Contributor
timestamp: June 03, 2025, 08:28:21 pm
content: Quote from: gamalot on June 01, 2025, 08:22:03 amThey're using a male USB C instead of a female USB C.There are some reduced pincount USB C male parts on the market, but dramatically less. I was able to find some by filtering on LCSC. A lot seem to be mid-board-mount types, so make sure you have the cutout & footprint well matching.

author: gamalot
author_rank: Super Contributor
timestamp: June 03, 2025, 08:50:31 pm
content: Quote from: Whales on June 03, 2025, 08:28:21 pmYou are right, my bad, my English ...

author: Whales
author_rank: Super Contributor
timestamp: June 04, 2025, 08:29:16 am
content: Don't worry, it's not just your English. Words to describe connectors are difficult. I could start an argument by asking "do headphones have an audio jack?"

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 07, 2025, 01:57:18 am
content: You can buy USB-C connectors on Aliexpress that have a breakout PCB for just the power for around 50ct. And there are lots of small variants too, so shop around a bit. USB-C is very fiddly to solder yourself.
Designing a PCIe edge connector in Eagle. - Page 1
Forum section: electronics / beginners

author: UTF_8x
author_rank: Newbie
timestamp: October 22, 2018, 12:41:37 pm
content: Hi. I'm trying to make a board with a PCIe edge connector on it in Eagle and I'm using the pre-made component from thecon-pclibrary (PCI-E-164SLOT). This component comes with the appropriate pads and board shape. My question is, how do I connect the outline of my board to the predefined outline of the connector? (please see attached image)Thank you.

author: t1d
author_rank: Super Contributor
timestamp: October 26, 2018, 07:23:50 am
content: You need to look at the data sheet, for the connector, and see if there are any directions. The manufacturer could, surely, help you. Feel free to call them. It is typical, for designers to check with them.An easy method is to put the connector on the Eagle board, where you think it will go, print the board layout, at 100% scale, and match the actual component, to the board. You should do this, as a part of your regular design practice, anyway.
Designing a PMSM controller   - Page 1
Forum section: electronics / beginners

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: March 21, 2018, 10:58:41 am
content: Hi there,I need a suggestion how could I proceed, in Matlab simulink or Ltspice,Take a look my control diagram, mathematically I have managed all factors and formulas,In a permanent magnet synchronous motor where inductances vary as a function of rotorangle, the 2 phase (d-q) equivalent circuit model is commonly used for simplicity and intuition.Need PI control, clarke and park transformation as well.I will be happy if you can provide me any matlab code or similation file to study more.Few factors are considerable,Motor ParametersVa = 18  line-to-line voltageLq = 0.050  q-axis inductanceLd = 0.005  d-axis inductanceRs = 1.20  per phase stator resistanceVs0 = Va*sqrt(2)/sqrt(3)  No-load line voltagenmax = 20000  Maximum speedIs = 3.0  Limited currentP = 4 [ ] Number of polesFsw = 50kHz Switching frequencyTorque @ 0 rpm = 0  Start-up torqueTorque ramps-up in 2sSteady-state torque @2s = 2.1

author: ahbushnell
author_rank: Frequent Contributor
timestamp: March 21, 2018, 02:21:40 pm
content: Quote from: Md Mubdiul Hasan on March 21, 2018, 10:58:41 amHere is a TI white paper on motor control.https://www.ti.com/lit/an/bpra073/bpra073.pdf

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: March 21, 2018, 09:41:40 pm
content: Thank you sir,I have collected similar concept s.But, need to make my won code in simulink.Take a lookhttp://www.sosw.poznan.pl/tfitzer/pmsm/

author: ahbushnell
author_rank: Frequent Contributor
timestamp: March 21, 2018, 11:16:16 pm
content: Quote from: Md Mubdiul Hasan on March 21, 2018, 09:41:40 pmNice but why are Iq and Id changing in steady state?

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: March 26, 2018, 12:22:04 pm
content: Not sure
Designing a power supply for portable DAC/headphone amplifier - Page 1
Forum section: electronics / beginners

author: kendo
author_rank: Newbie
timestamp: December 30, 2020, 05:50:29 pm
content: Im designing this portable audio receiver and DAC/headphone amp for fun and Im a bit stuck at designing the power part of the board. Im going to have it powered with two Li batteries in paralel (3.7V) and I need to get a few voltages out of it.I need 3.3V and 5V for powering the digital and logic parts and for the analog parts I need fairly low noise 3.3V for SPDIF chip and low noise +5V -5V for the DAC and the amplifier. The max current for the logic should be around 100mA and around 200mA for the +-5V and about 25mA for the 3.3V powering the SPDIF chip.So my first problem is that I dont know how much noise should be on the analog power lines.Other than that I dont really know how to design this power supply since Ive never done anything where I need fairly low noise analog supply and noisy digital supply out of a battery.Im pretty sure some of you have already done this kind of work so Im looking for some general help, ideas and even some application notes to read.

author: ve7xen
author_rank: Super Contributor
timestamp: December 31, 2020, 12:27:09 am
content: For a USB DAC/HP amp project I used a power supply based on TPS65131 switcher to generate +/-9V from VUSB. For VA I used a LP2985 off the +9V, and the 3.3V supplies were LP2985s directly off of the VUSB. This design used a CS4398 DAC and I was able to achieve -106dB RMS noise floor up to 48KHz, and considerably better up to 20KHz only. LP2985 isn't particularly high performance and only offers about 50dB of rejection, so you might do a bit better with something fancy like LT3042 or TPS7A4901. The switching regulator on its own generates pretty stable rails, I don't think it's anything particularly special either, I'm working on a new project using TPS54331 instead just to generate a - rail where I already have the + from outside.As far as how much noise you can tolerate on your power rails, it will be a combination of the ripple rejection of your regulators and the PSRR of your DAC/amps, and what an acceptable output noise is. You can work backwards from your budget. Say you will tolerate noise 100dB down from the full-scale output of the DAC. Naively, if your DAC offers 60dB PSRR, then your noise needs to be at least 40dB down to meet your goal. You might get a couple extra dB from differential outputs, and the real world will interfere with this, but as napkin math it will get you in the ballpark.Your current budget on the +/- rails seems very high to me.
Designing a PS_ON and PS_OFF circuit for Power Supply - Page 1
Forum section: electronics / beginners

author: Cyo
author_rank: Newbie
timestamp: November 12, 2020, 05:46:54 pm
content: Hey guys,I'm in the process of designing a new power supply for an old Japanese computer. I have a pin out of the voltages for all pins and I can successfully turn the computer on by wiring a pico PSU to a breadboard with the 44pin high density backplane connector that connects to the computer. I press the power switch on my pico breakout board and it shorts the PS_ON line to ground on the pico turning the computer on. However when I do this I cannot press the front power button on the computer to turn it off or on.I'm in a dilemma. Currently the design can turn the computer on but I require a second switch in the rear specifically making the front power button obsolete. There is also a software shutdown feature in the computer software that also shuts the PSU off and I'm not sure how to implement this in a circuit.The pin that performs a software shutdown is an active high and goes low when the PSU cuts off basically when you select computer shutdown in the operating system. This I do know. I'm welcome to any suggestions to try out by others more experienced here

author: m k
author_rank: Super Contributor
timestamp: November 14, 2020, 08:22:26 pm
content: What kind of a switch the original one is?Active high means that level is low when shutdown is not shutting the power.To use something like that the PSU must support it.

author: Jwillis
author_rank: Super Contributor
timestamp: November 15, 2020, 07:42:10 am
content: What about a soft latch circuit and relay. A CD4011 Nand gate comes to mind.

author: m k
author_rank: Super Contributor
timestamp: November 17, 2020, 09:00:52 am
content: NAND is good, even better that 4011 is a quartet.Shorting NAND inputs is usually simple, that way you get an inverter.By inverting NAND inputs you get OR.You still have a spare gate so you can get NOR.https://en.wikipedia.org/wiki/NAND_logic

author: SmokedComponent
author_rank: Regular Contributor
timestamp: November 17, 2020, 09:27:41 am
content: Using CD4093 (Schmitt-trigger NAND) is better in this case, when interfacing with buttons and slow(ish) events and not other CMOS/TTL logic.

author: m k
author_rank: Super Contributor
timestamp: November 18, 2020, 12:31:17 pm
content: One is still missing, open collector.(cd74hct03)https://en.wikipedia.org/wiki/Open_collectorFor the device in hand,PWR_ON ->PWR_GOOD ->PWR_OFF/ON <-Many times the first one is the only one that is presented.In that case the current power on method must be replaced.
Designing a simple battery balancer - Page 1
Forum section: electronics / beginners

author: Prithul0218
author_rank: Contributor
timestamp: October 04, 2018, 04:28:06 pm
content: Hi.I am designing a battery balancer using Arduino. It's pretty simple. if one cell has higher voltage than others, the balancer will discharge it til it matches the voltage of the other ones using a resistor. I am making it for 3.7V LiPo batteries, maximum 4 cell for now. I attached the schematic I designed below. I just wanted to ask you guys if everything is okay or not. Also feel free to give me suggestions.Note: The balancer is a passive one, it turns the power taken from higher voltage battery into heat. I chose 22 ohm resistor. Battery full charge voltage will be 4.2V. The mess of resistors is because I used the values that I currently have in my lab. VCC is 18V and the MOSFET is a logic level one.TL;DR: Check if there's something wrong with the schematic for a battery balancer.
Designing a USB stick? - Page 1
Forum section: electronics / beginners

author: fubar.gr
author_rank: Unknown
timestamp: September 22, 2016, 04:46:15 pm
content: I want for fun and giggles to design and make my own USB memory stick.I opened up a stick I already had and basically all there is to it is a memory chip and a USB interface chip.The interface chip was an Innostor IS902 and the memory something made by Toshiba. Googling the part names didn't yield any datasheet. I went to the Innostor website but there's nowhere to download a datasheet. Apparently they sell directly to manufacturers?So I would like some guidance on what parts I could use that are readily available on Digikey, Mouser or TME.

author: Jeroen3
author_rank: Super Contributor
timestamp: September 22, 2016, 05:17:07 pm
content: Any microcontroller with USB and EMC. If you buy a USB Flash Controller there is a chance it's a special purpose 8051 controller

author: fubar.gr
author_rank: Unknown
timestamp: September 24, 2016, 05:56:10 pm
content: Quote from: Jeroen3 on September 22, 2016, 05:17:07 pmI was searching with the wrong terms, that's why I couldn't find any results. So "USB Flash Controller" is the magic phraseI see these controllers have quite a lot of logic in them. I was under the impression that they were quite dumb.Thanks! I'll start a new topic in Projects... to show my progress.
Designing an electromagnet? (#of turns, diameter, etc) - Page 1
Forum section: electronics / beginners

author: SuperJeep
author_rank: Contributor
timestamp: December 29, 2011, 11:00:35 pm
content: Hi, I've started a new project to learn about using feedback in microcontrollers and I've already hit a wall haha.I'm trying to make an electromagnetic levitator to float an object like a coin, using PWM through an electromagnet and using a hall effect sensor for feedback on how hard to drive the solenoid.(kind of like those floating globes one can buy)My problem is i first need to know how to design an electromagnet. It needs to pick up something relatively small, like a coin, and be able to hold it in the air (roughly 3-4cm away).I have different awg enameled wire which i plan to use but i dont know how to pick my design constraints:-wire gauge-number of turns-length of the solenoid-diameter??Thanks for any help! I'm asking here because I've had nothing but great assistance from eevblog in the past.

author: IanB
author_rank: Super Contributor
timestamp: December 29, 2011, 11:08:44 pm
content: It's going to be somewhat like designing transformers and coils, in as much as you will need to know the magnetic properties of the core and its area and relate that to the current in the windings. It will be complicated by the fact that an electromagnet is not a closed magnetic circuit but is usually open ended.You might start at this very nice tutorial to get an idea of where to begin, but I doubt it will be the end of your journey:http://ludens.cl/Electron/Magnet.html

author: SuperJeep
author_rank: Contributor
timestamp: December 31, 2011, 05:27:25 pm
content: Thanks for the link it proved very useful! I simply took advantage of the linear relationship between number of turns and flux density and just wrapped 250 turns, using an Allen key as the core. Works decently at picking up a coin at a 50% duty cycle with a 5v source and that gives me tons of room for tweaking,thanks again.
Designing an undervoltage lockout circuit - Page 1
Forum section: electronics / beginners

author: mkapalla
author_rank: Newbie
timestamp: January 31, 2021, 09:36:34 pm
content: Hi!I am trying to create an undervoltage lockout circuit for protecting a single cell Li-Po accumulator. I want the circuit to cut off at 3.45-3.5V.I already did a little research on the topic and found a solution I like (uses only 4.5µA, provides hysteresis,https://www.analog.com/en/technical-articles/battery-protection-circuit.html). The problem now is that the circuit cuts off at 3V and switches back on at 3.092V.Do I understand correctly if I want to change the cutoff and the hysteresis voltage that I need to adjust all resistor values? If so, how do i calculate the values for R1 and R2? I tried to use the voltage divider formula but i got a result that -in my opinion- didn't make sense.For R3 I calculated 2.6MOhm with R4 being 150kOhm. (Based on a cutoff voltage of 3.45V) Is this correct?Maybe someone could give me an explanation or even an example on how to calculate the values for R1 and R2, R5 should be easy when the other values are known.Thanks in advance(Attached you can see the circuit)

author: mkapalla
author_rank: Newbie
timestamp: January 31, 2021, 11:01:00 pm
content: I think I got the solution myself.I got the following values so far:R1 = 3,57MR2 = 3 M(R1 and R2 are kept, apparently I just misunderstood what I was calculating earlier)R3 = 2,34 MR4 = 406,25 kR5 still has to be calculated

author: Zero999
author_rank: Super Contributor
timestamp: February 01, 2021, 03:09:50 pm
content: R5 should be a low value, just to prevent oscillation, 1M is far too high, go with 100R.Consider using a comparator IC, such as the MCP6541, or LT1716, rather than an op-amp.

author: mvs
author_rank: Frequent Contributor
timestamp: February 01, 2021, 05:06:20 pm
content: Quote from: mkapalla on January 31, 2021, 09:36:34 pmYou can change all values, but it is not necessary.It would be sufficient to change only R1 for cutoff and R5 for hysteresis.R1 should be around 4.3 Meg for 3.45V.Note, that this high ohmic circuit is probably made for marketing/demo purpose and not intended for production. It is quite sensitive to leakage due contamination and moisture. Look better for integrated voltage supervisor ICs.
designing bench power supply.  - Page 1
Forum section: electronics / beginners

author: superwester
author_rank: Contributor
timestamp: May 05, 2018, 11:40:10 pm
content: Hello all,im designing (implementing?) a diy variable power supply around the lm338. inspired by dave's usupply but taking my own direction.that linear regulator has a minimum worst case load of 5mA according to the datasheet, so i was thinking of a solution hopefully not recurring to a current source ic and keep it discrete.i ended up with this bjt current sourcehttp://tinyurl.com/y8nctaopthe 5v will be fixed (maybe 3.3v later on)is this a good enough solution?any draw backs that im missing of?thank you in advance.

author: rdl
author_rank: Super Contributor
timestamp: May 06, 2018, 04:17:28 pm
content: The link does not work for me. However the LM338 is basically a higher current version of the LM317 and the minimum load requirement is usually taken care of by properly sizing the upper resistor in the divider which sets the output voltage (R1 in the diagram below).

author: superwester
author_rank: Contributor
timestamp: May 11, 2018, 05:14:44 pm
content: sorry for the lateness.Im aiming to drive the adj pin directly from a MCU, so i wont have that resistor to fix the problem
Designing motherboard for PNP auto feeders? - Page 1
Forum section: electronics / beginners

author: shai
author_rank: Contributor
timestamp: March 17, 2019, 07:33:05 pm
content: I'm working on a pick and place machine and designing my own auto feeder. Still kinda new to EE, so this project is a great opportunity for me to advance my knowledge on circuit board design.I've finished designing the feeder itself and now I need to design the "motherboard" that will control all ~30 feeders. The feeders work by (see attached pic) using an N20 motor to pull the cover off the tape and therefore advance it. The sprocket simply acts as an encoder. So four "pad clicks" by the springs, means it's moved 4mm pitch. The TWO springs on the back of the sprocket short themselves when touching a pad. (wether this is a good way to make an auto feeder is another topic). I am trying to understand, what's the best way to design the motherboard? I was going to use the Arduino Mega 2560 schematics and retrofit it onto this custom shaped board (attached pic) since I think using Arduino to write the code would be the easiest way to program this motherboard to communicate with OpenPNP software.Basically I have one PWM powered mosfet that acts as the "GND" to 30 other mosfets (motors). Each of the feeder mosfets is opened/closed using GPIO pin since Arduino Mega 2560 only has a limited number of PWM pins, but many GPIO pins. All the individual feeders' encoders feed to one pin since they will never be used at the same time (one feeder at a time). The encoder will only turn one direction all the time since turning the reverse will not move the tape.Is there a better way of doing this after looking at my description/pics? Suggestions?Thanks!

author: jmelson
author_rank: Super Contributor
timestamp: March 17, 2019, 08:18:46 pm
content: A mechanical encoder? No, I don't like that at all. How many parts will be exposed when the cover tape is lifted? Do you have a blade or cover to keep the parts from jumping out of the tape pockets? This is a REAL problem in P&P, see comments in manufacturing forum section, where P&P has been discussed a lot.My CSM84 feeders have no more than 5 parts uncovered, and the clamp covers 4 of them, and the retractable blade covers the most forward one until the nozzle is about to make the pickup.Jon

author: shai
author_rank: Contributor
timestamp: March 18, 2019, 01:43:46 am
content: Thanks, but as I mentioned, this post is not about the mechanics of it.

author: ebclr
author_rank: Super Contributor
timestamp: March 18, 2019, 02:12:10 am
content: Why not stepper motor ? it's made for this
Designing/Populating PCB's with SMD components on BOTH sides-How? - Page 1
Forum section: electronics / beginners

author: djsb
author_rank: Super Contributor
timestamp: April 04, 2023, 04:54:50 pm
content: I'm a total newbie when it comes to making and populating prototype PCB's with SMD components. One thing I'm wondering about is how to solder SMD components onto a DOUBLE sided PCB? I'm guessing it's fairly easy if using HAND soldering with a soldering iron. What is the technique required if using solder paste and a hot plate or reflow oven? It would make sense to put as many components as possible onto just one side of the PCB. But it would be a shame to not make use of both sides if possible.I'm primarily interested in a pragmatic way to work with one-off prototype PCB's. However, I need to have in mind how to design a PCB for possible larger volume production. How would a double-sided PCB be populated on a production line? Thanks.

author: mariush
author_rank: Super Contributor
timestamp: April 04, 2023, 05:07:21 pm
content: I would guess a common practice would be to use drops of glue under components, and do wave soldering or spread solder paste using stencil before the parts are glued down and then run the circuit board through an infrared oven or some other way of flowing the solder.seehttps://www.nexpcb.com/blog/how-to-use-smt-red-glue

author: barshatriplee
author_rank: Regular Contributor
timestamp: April 04, 2023, 05:40:06 pm
content: For double-sided PCBs with SMD components, the board will need to go through sequential reflow soldering unless you opt for hand assembly. Reflow soldering will be used on high-volume runs/low-cost prototyping runs, so designers should plan for reflow soldering during assembly.https://resources.altium.com/p/best-design-practices-double-sided-pcb-soldering-smd-parts

author: KaneTW
author_rank: Frequent Contributor
timestamp: April 04, 2023, 06:40:29 pm
content: Quote from: djsb on April 04, 2023, 04:54:50 pmYou do not need to do anything. Most parts will be held in place by surface tension (I forgot the weight/solder contact area threshold).For the parts that don't, you can glue them or use a lower-temp solder paste for the second pass.
Desktop clock - Page 1
Forum section: electronics / beginners

author: Savetheday
author_rank: Regular Contributor
timestamp: October 06, 2017, 01:41:32 pm
content: Hi everyoneMy friend has an old LCD damaged desktop clock.It's very valuable for her.It has LCD display that is no longer working.I would like to make it work again.I couldn't find any similar. I think I need to change Lcd display to 7 segments led display or something else. Have you any suggestions?thanks.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: October 06, 2017, 01:53:42 pm
content: No longer working... let us know exactly what that means.Typically there are segments missing, or dim. Typically it's the Z-strip ends are dirty. That would be the rubber thingy between the display, and the PCBA.

author: Savetheday
author_rank: Regular Contributor
timestamp: October 06, 2017, 01:57:31 pm
content: Quote from: SoundTech-LG on October 06, 2017, 01:53:42 pmLcd display screen was broken.I whipped out that rubber band with the alcohol

author: Savetheday
author_rank: Regular Contributor
timestamp: October 06, 2017, 02:26:13 pm
content: with some force, you could only read some parts of numbers.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: October 07, 2017, 06:18:27 pm
content: There is a difference between 100% isopropyl (use it), and rubbing 70%... (the addition of 30% oil). Do not leave any dirt/fibers on the contact areas.

author: tooki
author_rank: Super Contributor
timestamp: October 07, 2017, 09:49:24 pm
content: Quote from: Savetheday on October 06, 2017, 01:57:31 pmStop being vague. “Broken” doesn’t say much more than “doesn’t work”. Can you please describe the fault EXACTLY??Quote from: Savetheday on October 06, 2017, 01:57:31 pmDo you mean you cleaned (“wiped”?) it with alcohol? (To whip something out means to pull it out to show it... usually referring to a guy pulling his dick out of his pants.)Quote from: SoundTech-LG on October 07, 2017, 06:18:27 pmIn rubbing alcohol, the balance of the alcohol content iswater, not oil. (70% alcohol, 30% water happens to be the best for disinfecting skin — even better than higher concentrations apparently — but indeed for electronics, a higher concentration is better.)
Desktop PnP machine - vac settings - Page 1
Forum section: electronics / beginners

author: pete_flex
author_rank: Newbie
timestamp: December 06, 2019, 11:58:19 am
content: Hi,Can any users comment on how easy it is to dial in settings for desktop PnP machines?The settings that I'd be most interested in would be the vac %, head travel speed & placement speeds, vac hold timesthis would be to try & get settings for more fragile componentsI guess it's down the built in software & how easy it is to navigate to these settings & make changes.Any input wold be greatThanks

author: Ribster
author_rank: Frequent Contributor
timestamp: December 06, 2019, 09:27:46 pm
content: Depends vastly on the type of pick and place you mean. Do you have some desktop units in mind ?Head over to the assembly section, there are a lot of great threads about pnps.Read them, and you will already be a lot wiser.

author: pete_flex
author_rank: Newbie
timestamp: December 07, 2019, 09:09:43 am
content: I've emailed SmallSMT.Just waiting to hear back. Im in the UK so a company who have a contact in germany that looks after Europe would be good.Read some pages on the NeoDen units but unsure about the feeding problems. I'm sure all the benchtops have their issues & work arounds but I think it would be good to find one with decent software

author: Ribster
author_rank: Frequent Contributor
timestamp: December 07, 2019, 10:06:06 pm
content: What is your budget ?

author: pete_flex
author_rank: Newbie
timestamp: December 09, 2019, 09:14:22 am
content: I'd probably say up to £8k -£9kI don't think I wold get the budget for something like a Novastar
desktop specifications needed for an undergraduate in IC design? - Page 1
Forum section: electronics / beginners

author: snowstormnight
author_rank: Newbie
timestamp: May 10, 2024, 03:23:07 am
content: Hi everyone,I am a first year ECE student that is planning to do some IC design works this summer in a lab. Currently, I only have a macbook, which is appearently not enough for such work. Thus, I am thinking about building a PC for the task. Can anyone suggest some specification for the task? I would likely to be working on some RISC-V, in-memory computing archicture, and systolic array archicuture design.Any suggestions will be greatly appreciated!Thanks in advance!

author: Andy Chee
author_rank: Super Contributor
timestamp: May 10, 2024, 04:13:52 am
content: Multi-monitor setup would be my suggestion.
Desktop virtualization: Linux inside Windows or Windows inside Linux? - Page 1
Forum section: electronics / beginners

author: Veliz
author_rank: Contributor
timestamp: August 24, 2012, 07:34:25 pm
content: So i created a thread few post down that got very good info, now how about this topic? Saw an article this morning about it (http://www.123unix.com/2011/linux-windows-guest-vs-host/) What do you guys think/do?And lets make it only virtualbox or Vmware workstation.... So kvm or qemu wont come upTo make it fair

author: firewalker
author_rank: Super Contributor
timestamp: August 24, 2012, 08:01:22 pm
content: There is no right answer to such a general question.Are you familiar with Windows or GNU/Linux? The guest OS will need to "talk" to particular hardware? Are you going to use a rolling release distro?Axiomatically: If your main OS is Windows you will choose Windows as host. If your main OS is GNU/Linux the host will be GNU/Linux.Alexander.

author: poorchava
author_rank: Super Contributor
timestamp: August 24, 2012, 09:44:42 pm
content: I'd rather go with windoze as host. It's simply more compatible with everything (or rather everything with windoze). Linux is good if you need free OS for your office and don't want to pay for windoze. other use is to set up some server-like stuff. Linux is simply too unpredictable to use as a main system. Not meaning that it's unstable, because it indeed is stable. Rather the fact that you can screw up whole system with one bad command. Of course you cannot screwup Linux to the point where you cannot fix it, but in some cases you'd have to spend weeks before you figure out how to do it.btw. i mean 'true' Linux (Slackware, Arch, PuppyLinux etc) not some bloated eye-candy 'consumer grade' Linux (Ubuntu?)

author: GeoffS
author_rank: Unknown
timestamp: August 24, 2012, 11:50:11 pm
content: As previously said, go with the host operating system that you're most comfortable with. Both Windows and Linus are well supported by VMware both as hosts and guests.If you're just starting out with Linux and don't want to commit to installing it on your hardware while you learn/test then stick with Windows as your host.I run Linux (Centos) as a host OS and VMware Workstation with Linux and Windows guests.

author: Psi
author_rank: Super Contributor
timestamp: August 25, 2012, 01:35:49 am
content: Linux will play nice inside a VM (if there are bugs people will fix them)Where as your rely on microsoft to fix and bugs running Windows in a VM.So yeah, i would run windows as the host and linux as the VM.
Desolder a crystallised solder joint - Page 1
Forum section: electronics / beginners

author: _ar_
author_rank: Contributor
timestamp: April 14, 2018, 05:55:03 pm
content: Hello All,I have a PCB with battery acid damage. I tried to desolder the battery pack and managed to do so for the 2 + terminal. However the - terminal's solder joint got the biggest hit from the battery. I just could not flow the solder no matter what I tried: used higher temperature, use a solder sucker, flooded the area with flux from a fluxpen, tried to heat both sides of the joint. Also tried to reflow the joint, but the solder barely melted, I could move it around somewhat and it would not take fresh solder. I ended up cutting the terminal. What is the best way to deal with such joints?Thanks,_ar_

author: jmelson
author_rank: Super Contributor
timestamp: April 14, 2018, 07:50:12 pm
content: Dilute the solder with fresh solder, preferably SnPb or low melting point solder. Possibly, somebody soldered it with high melting point solder in the past. The fresh tin-lead solder should lower the melting point enough to make it possible to disassemble it.Jon
Desolder Capacitor 400v 33uF Safetly? - Page 1
Forum section: electronics / beginners

author: xan
author_rank: Regular Contributor
timestamp: February 26, 2017, 01:18:00 pm
content: Hi Everyone,i need to desolder this Cap 400v 33uF i'm not an expert so i ask what i should take care? i need to short it before desoldering ????Thank's!

author: singapol
author_rank: Frequent Contributor
timestamp: February 26, 2017, 01:31:42 pm
content: From my experience these low uf caps will lose it's charge a few minutes after power is switched off butif you can't wait then use a 500 - 1K ohm 5 watt white ceramic power resistor with uncut and heatshrinked sleeved leads to discharge safely. If very big caps use safety eye goggles.

author: xan
author_rank: Regular Contributor
timestamp: February 26, 2017, 01:33:23 pm
content: ahh ok so it will be safe 'cause it some years this board it's gone! thank's !!!

author: kripton2035
author_rank: Super Contributor
timestamp: February 26, 2017, 01:43:29 pm
content: measure the voltage at the capacitors pins, using a multimeter. it should be near zero if it's been off for years.

author: xan
author_rank: Regular Contributor
timestamp: February 26, 2017, 01:59:41 pm
content: yes of course 0! with my tester )) tnx!

author: Gregg
author_rank: Super Contributor
timestamp: February 27, 2017, 05:22:07 am
content: Small incandescent lamps make fun capacitor discharge devices which allow the user to see the results; just pick an appropriate voltage rated lamp. Also an analog meter will slowly discharge a capacitor; but I may have just revealed my age.

author: kripton2035
author_rank: Super Contributor
timestamp: February 27, 2017, 08:25:45 am
content: there are also some handy tools (and cheap too) to do this job.http://www.dx.com/fr/p/repair-tools-sparkpen-capacitor-discharge-pen-for-camera-mobile-phone-home-appliances-129179#.WLPiV3p_d9I

author: tggzzz
author_rank: Super Contributor
timestamp: February 27, 2017, 09:18:14 am
content: With any capacitor having voltages that could hurt, be aware of the phenomenon known as "dielectric absorbtion" or "soakage". The effects are as if an isolated capacitor slowly "recharges itself" after being discharged.
Desolder SMD BA5984FP - Ic is glued on the board - Page 1
Forum section: electronics / beginners

author: herr-stromberg2010
author_rank: Newbie
timestamp: November 05, 2011, 09:11:00 am
content: Hi,I have problems to remove the BA5984FP vom a pcb. I can use a tweezer or the hot air gun, but the ic is fixed by a very hard to remove glue, mostly I removed the IC the glue destroys the pins on the boad. If this f... glue would not be there It will be easy to do.Can you tell a newby what to do? or what to use to solve this probs.?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 05, 2011, 10:03:31 am
content: Most glues can be softened with hot air.The way I'd do it is to unsolder the pins with braid, use a knife to ensure all pins are completely free, then heat gently for a while (lower then desolder temperature) while lifting the IC body with a knife.
Desoldering BGA witjh hor air - Page 1
Forum section: electronics / beginners

author: Aigor
author_rank: Contributor
timestamp: April 27, 2017, 08:56:59 am
content: Hi friends, before posting i did some search into forum, but it seems no one post this question.I have a hot air gun and i would like to try to desolder some bga chips, not big like gpu but small like memory chips.Someone can show me process and temperature in Celsius ?or some tricks to use ?Many thanks

author: vealmike
author_rank: Regular Contributor
timestamp: April 27, 2017, 09:36:06 am
content: You'll find that removal is much easier if the PCB is pre-heated using a hot plate. Place PCB over plate and give it plenty of time to warm up. Leave the PCB on the plate whilst working with the hot air gun.Exact temperatures and timings are something that will depend on the volume of air that your airgun can shift and the amount of copper in the PCB sitting acting as a heatsink for the chip.Best advice is to practise on a scrap card.

author: james_s
author_rank: Super Contributor
timestamp: April 27, 2017, 08:43:39 pm
content: Are you wanting to reuse the PCB or the ICs? Both? If you don't care about the PCB, you can just heat it from the back side with a heat gun and tap it until the IC(s) fall off. If you don't care about the IC, you can do the same from the top, heating the IC until it comes off without force. If you intend to reuse both then you have to be more careful.
desoldering capacitors, resistors and other components for testing - Page 1
Forum section: electronics / beginners

author: electron_jj
author_rank: Newbie
timestamp: August 30, 2021, 03:12:57 pm
content: Hi everyone, does any know if the process of desoldering capacitors, resistors and other components out of the circuit board may risk damaging these components in the process? The power supply board that I have been desoldering components out of uses lead free solder so the temperature of the solder is around 370 degrees and may even be higher. As I am new to electronics and still mastering the skill of desoldering, it had taken me longer time than average to desolder any component, say around 3-5 minutes or so and even more if there are residual solder in the through hole which takes even more time to disconnect the component. During the process, would the 370 degrees heat get transferred to the inside of the capacitor, resistor etc. and damage them? So far, the components that I have disconnected from the circuits all tested okay out of circuit. But in order to find out where the problems lies in the circuit, I anticipate I will need to desolder many more components to check, and I am concerned that the desoldering process may damage these components also. Grateful for any advice on this. Thanks!

author: Kerlin
author_rank: Regular Contributor
timestamp: August 30, 2021, 03:33:16 pm
content: Sorry but fixing a power supply by desoldering each component and checking it is not the way to go.Highly unlikely you will fix it that way.You have skipped the whole process of studying the way power supplies work and then learning and applying fault finding techniques.The maximum soldering temperature is often supplied by manufacturers on their data sheet, if you can't find a data sheet for that particular one then often a data sheet of similar components will do.Generally if using correct practices desoldering and soldering through hole components components causes no problems. Surface mount components usually do have critical soldering requirements.Also as a general guide if you spend more than six hours soldering a power supply PCB then consider it scrapped.

author: electron_jj
author_rank: Newbie
timestamp: August 30, 2021, 03:54:14 pm
content: Thanks!

author: Kerlin
author_rank: Regular Contributor
timestamp: August 30, 2021, 03:56:22 pm
content: Just added a bit to that