hybridfree/eevblog-posts huggingface dataset:
Adding data to a dumb POE device - Page 1
Forum section: electronics / projects

author: JMG
author_rank: Contributor
timestamp: October 06, 2020, 10:22:13 pm
content: Hi, new member, first post.I have a project that is basically a device connected to POE and is switched on as soon as its connected, but now I need to have some communications with this device and add some intelligence. Having had zero to do with Ethernet connectivity, I'm clueless, and not even sure what terms to search.I'm trying to create a connection where I can receive data from this device and send back calibration values from a mobile app or by logging in to a website or even the device itself. I understand I need a microprocessor in the device and have experience with 8 bit PICs. What I don't have is is experience getting a PIC to communicate over Ethernet with an app.Could someone point me in the right direction? Thanks!

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 06, 2020, 10:48:15 pm
content: Look up "Ethernet Shield" to get an idea of how it's done with the classic Arduinos. Do note that implementing TCP/IP from scratch probably isn't the best idea unless you really want to learn how it works.

author: george.b
author_rank: Frequent Contributor
timestamp: October 06, 2020, 11:10:59 pm
content: The ENC28J60 is probably what you need.https://www.microchip.com/wwwproducts/en/en022889

author: fordem
author_rank: Regular Contributor
timestamp: October 07, 2020, 02:24:42 am
content: So, in essence what you're trying to do is add smarts to a dumb device? Ever thought about approaching it from the opposite angle? It might be easier to get a smart device to do whatever the dumb device does.There are quite a few SBCs with GPIO that can be used to interface with or control another device - my experience has been limited to the Raspberry Pi, which as of the 3B+ can be powered via a PoE hat, and also supply power (5V) to a connected device.What does the dumb device do or need to do, and what data do you need from it?

author: JMG
author_rank: Contributor
timestamp: October 07, 2020, 04:00:03 am
content: All good answers. What I'd like to do is throw a pic on the board, and an interface IC or driver between the pic and the cable, if that makes sense. Adding an SBC would be too large, expensive and over kill. And no, I don't want to get in to figuring out the stack lolI'll check out the shields and the ENC28J60. Thanks guys!

author: magic
author_rank: Super Contributor
timestamp: October 07, 2020, 05:29:43 am
content: Many years ago I have seen a project involving 10Mb Ethernet on one of the classic AVR micros and I'm pretty sure the guy didn't code it all by himself but adapted libraries available on the Internet. Not sure if it bitbanged Ethernet directly or communicated with some external PHY.editPossibly this?http://www.pa3fwm.nl/projects/avreth/
Adding electric power to mountain bike - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 22, 2018, 04:50:19 pm
content: I have 0 knowledge regarding the motor/esc requirements of the bicycle so maybe someone can guide me here.My weight is around 70+ kg and I want a top speed of around 50 KM/h since I want more torque for hill climbs and fast acceleration.I have a 3D printer on hand for designing/ printing mounts and supports for the assembly.Any information would be of great help thanks!

author: mtdoc
author_rank: Super Contributor
timestamp: October 22, 2018, 04:52:47 pm
content: endless sphere e-bike techinical discussion forum

author: ahbushnell
author_rank: Frequent Contributor
timestamp: October 22, 2018, 05:01:08 pm
content: Go to the librarySent from my SM-G930V using Tapatalk

author: tpowell1830
author_rank: Frequent Contributor
timestamp: October 22, 2018, 06:36:45 pm
content: Tom Stanton does a DIY electric bike on his channel, here is the link to the first video, there is a series.Hope this helps...EDIT: I have watched many of Tom's videos and he uses solid engineering principles and thought process in his builds and I am quite impressed.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 22, 2018, 07:34:27 pm
content: Quote from: tpowell1830 on October 22, 2018, 06:36:45 pmI saw that and got excited until i realized it was only possible to fit to his specific bike.Will learn all I can and try to integrate the system into mine.

author: jose347
author_rank: Contributor
timestamp: October 22, 2018, 08:40:05 pm
content: Quote from: drummerdimitri on October 22, 2018, 04:50:19 pm50 KM/h sounds a lot for MTB, I am not saying it cannot be done, but those are numbers that you may see in a road bike, the highest number you will see in a trail are in the 35ish, anyway what you could do is search for average number people give on a power meters, you should look a steady power not spikes you will see that they will around the 300-400watts range you can use that to convert to HP and that should give you an estimate of how big your motor should be and with a motor then you can estimate battery and capacity, I least that should be your starting point.
Adding HS current and voltage measurement on OLED Like this board - Page 1
Forum section: electronics / projects

author: wissa
author_rank: Newbie
timestamp: December 26, 2021, 11:18:33 pm
content: Hi,I have seen this project on KickStarter and I am interested in making something close to it but with voltage and current for each output. Please see the project first on this linkhttps://www.kickstarter.com/projects/wissa/mini-power-stationBTW, it is a great project, I back it to get two. I am thinking of two solutions and please advise me1- Use one small package uC like Atiny85 and by I2C I can read from hall effect current sensors and write on OLED2- Use bigger uC and read from hall effect current sensors (I2C or Vout) and write on OLEDI am sticking with hall effect because don't want voltage dropping the outputs ... not easy on low side because of shared outputs.The first approach I will not be able to measure the voltages without using a multiplexer as low number of pins are availableThe target current is 0 to 5A ... Accuracy and bandwidth are not really crucial as the cost is the main concern.What do you THINK

author: wissa
author_rank: Newbie
timestamp: December 29, 2021, 09:14:30 pm
content: Any reply ?

author: inse
author_rank: Super Contributor
timestamp: December 30, 2021, 10:30:08 pm
content: Looks like an over-engineered gadget to me.By the way, the shunt voltage drop can be compensated by using an adjustable regulator.Do you really want to run 5A through a breadboard?

author: wissa
author_rank: Newbie
timestamp: January 04, 2022, 06:45:17 pm
content: I meant by 5A as the range that the sensor can pick up for transient for example but it would not run through breadboard ... 3A is ok .. also the kit can work as standalone with the extension
adding LED strip output to primarily 24vmotor driver board: circuit protection? - Page 1
Forum section: electronics / projects

author: k8943
author_rank: Regular Contributor
timestamp: December 11, 2019, 05:27:24 am
content: Have a board with uC + stepper driver - it's powered by 24v and has a local 5v buck. Suddenly would like it to drive 20cm of bright 24v LED strip as well (circa 0.3A max).First thought was a SOT-23 N-mosfet (circa 1.5A max) with a resistor pulling the gate down to ensure off at startup, PWM from uC thereafter. Then started to wonder about circuit protection (shorts in the lighting circuit). Would it make sense just to use a chunkier TO-220 mosfet and rely on the circuit protection at the 24v supply (cuts out around 2A with sense resistor + polyfuse on AC side)? Or is it appropriate to use something more dedicated? (Never used LED strip before.)
Adding over-temperature protection to a LiPo battery - Page 1
Forum section: electronics / projects

author: angust_uk
author_rank: Regular Contributor
timestamp: August 21, 2024, 09:02:12 am
content: I am looking to design a product that uses an off-the-shelf audio board powered with a small LiPo battery (this sort of thing:https://www.alibaba.com/product-detail/Voice-Cards-Music-Mp3-IC-Recording_1600451014222.html).However while the battery includes a protection circuit, there is no temperature sensor for disabling charging when too hot (a requirement that I have been advised must be met).I am investigating a few options (modifying the charging circuit for example), but was wondering whether there are any 'in-line' solutions that could be connected in series between the host PCB and battery that would achieve this. I could use a simple thermistor plus comparator and MOSFET, though I'm concerned the current consumption may have a noticable impact on battery life. An off-the-shelf IC would be ideal, but I can't seem to find anything suitable.Any suggestions would be apprecated!

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 21, 2024, 05:33:07 pm
content: Good Morning Angust, I believe most, if not all, BMS modules include temperature monitoring. Many are attached and appear to be part of the battery.

author: thm_w
author_rank: Super Contributor
timestamp: August 21, 2024, 11:36:02 pm
content: Theoretically you could just use one of these KSD9700s:https://www.aliexpress.us/item/2255799961105403.htmlWould be an odd solution though.

author: angust_uk
author_rank: Regular Contributor
timestamp: August 22, 2024, 08:17:05 am
content: Many thanks both!thm_w - that is one of the solutions I was considering, but agree that it is unusual!BILLPOD - that's what I thought, though after a closer look at many common protection ICs, they only include voltage & current monitoring (e.g. S-8209A):

author: Chalcogenide
author_rank: Regular Contributor
timestamp: August 22, 2024, 08:44:56 am
content: If the requirement is to interrupt only the charging, you could simply power the comparator from the USB input, and make sure that the unpowered circuit defaults to Mosfet ON. This way you have no parasitic current consumption in standby. Obviously the real solution would be to design your own charging circuit with over-temperature shut-off bypassing the charging circuit of the audio module.
adding short circuit protection to an FPGA board - Page 1
Forum section: electronics / projects

author: Dmeads
author_rank: Regular Contributor
timestamp: March 31, 2020, 10:57:17 pm
content: Hi! I am making a custom PMOD ADC for a Digilent Arty z7 boardhttps://reference.digilentinc.com/reference/programmable-logic/arty-z7/reference-manual?_ga=2.102800516.503493984.1585693245-795021002.1571863124The pins I want to use are routed as high speed differential, but can be used as single ended as long as one of the pairs is driven low from the FPGA. The high speed part comes from no protoecton resistors in series with the pins. the board has pads for them but they are loaded with 0ohm shunts right now. I want to add some resistors for short cirfcuit protection. the other pins on the board have 200 ohm resistors in series to limit current to 16.5 mA. I was goingn to add 200 ohm resistors but was wondering if it is okay if i leave the shunt on there?I just dont want to mess up the board because it was pretty expenseive for me. I would also make sure the 200 ohm one is in series with the shunt. Also I dont care about the "high speed" part because I am running sub 1MHz

author: OwO
author_rank: Super Contributor
timestamp: April 01, 2020, 04:59:42 am
content: You don't need short circuit protection on the GPIOs. What you might want is overvoltage protection which is what those resistors are for, if used in combination with a clamping diode.
Adding snubber capacitor to HVDC Brushed motor - Page 1
Forum section: electronics / projects

author: taoybb
author_rank: Contributor
timestamp: January 29, 2022, 09:41:26 am
content: Hello, I know it's kind of easy topic but when coming to work with direct 220VAC so I need some confirmation and more info. Mine grinder using DC brushed motor and ran off 220V(DC). The grinder use only diode bridge to convert 220VAC to dc then directly feed to the motor, also last time it blow diode bridge which rated at 15A 1000V (GBJ 1510) while motor only rated at 180W (DC resistance is around 80ohm) and speed is 2900 RPM.After changed diode bridge and grinder came back to life which bring up my though that adding snubber capacitor should prolong Brushed and Diode life? I got plenty of 1000pf/2KV ceramic cap lying around, is this capacitor a suitable? How many should I add?

author: SeanB
author_rank: Super Contributor
timestamp: January 29, 2022, 12:03:52 pm
content: Normally around 10n 2kV, and a series 33R 1W resistor will do. Add across motor terminals, and add again across AC input to bridge rectifier. Also good idea to add MOV across the input, 275VAC rating, to handle the voltage transients as the power turns on and off, and you can add some across the motor as well, 470V will work and clamp well enough to keep the diodes from being damaged by transients.The MOV units though will do more for the clamping than the capacitors.

author: taoybb
author_rank: Contributor
timestamp: January 30, 2022, 09:42:03 am
content: Thank you, I added part as you said but with slightly different value because I can't find value you advised. I install 2x 1000pF and 100 ohm resistor, I don't have any MOV but will be add in the future. Now it seem to work fine. It's good to ask first, I almost add capacitor without series resistor
Adding Test points to a PCB - Page 1
Forum section: electronics / projects

author: mendez
author_rank: Regular Contributor
timestamp: October 04, 2019, 12:43:41 am
content: I'm trying to add test points to my PCB so that I can monitor/sense analog signal with an oscilloscope or a test lab box WITHOUT causing interfering/adding noise to the data. The question is: can someone point me to the right direction on how to do this?I plan on using BNC connectors and Test Points.Please see attachment for an example of what I'm trying to accomplish.

author: DaJMasta
author_rank: Super Contributor
timestamp: October 04, 2019, 05:07:12 am
content: It depends on the sensitivity of the sensor, the thing measuring it, and its output characteristics, so it can be a complicated thing to answer.That said, if you're measuring the sensor directly with the micro, it's probably not all that sensitive to a lot of noise (there's already a fair amount built in), so make sure your measuring instrument has a fairly high impedance and use shielded cables to connect the points and the device. Basically what you'd have to worry about is noise picked up on the measurement line, provided your source impedance is low enough that the added measurement of it doesn't draw the voltage down (and provided this is a voltage measurement), but unless your test points are in a shielded box, you're still gonna get at least a bit picked up on the board itself.If it were me? Add test a test point for the signal and ground (a solder-in loop is great for oscilloscope hookups, but you can use wide through hole pads on the edge of a board or a bit of wire with a loop soldered to a blank pad), keep them fairly close together, and just clip the probe in normally. A scope isn't going to be super high resolution on the vertical scale (they're not designed for it), and your micro is probably reading its ADC with similar or slightly higher noise levels than the scope, so it's likely that your application is not sensitive enough for the probing to matter much. The easy sanity test would be to measure your device on the micro, then connect the scope and measure on the micro again. If the readings are consistent, your scope probe probably isn't injecting enough noise to make a problem.

author: tautech
author_rank: Super Contributor
timestamp: October 04, 2019, 05:24:28 am
content: Place a 0805 footprint onto the traces you need to get measurements from. Assign both pads to the same net as the trace. Take your pick from these SMD test points and just solder them on.https://www.digikey.co.nz/en/product-highlight/k/keystone/surface-mount-test-pointsI like the first one, it's small and tidy and easily reusable.Normal scope probes grabbers have no trouble securely connecting to them.
Adding the 'missing' VR1 to a Won Hung Lo FG-100 iron temp knock-off - Page 1
Forum section: electronics / projects

author: 6SN7WGTB
author_rank: Regular Contributor
timestamp: September 19, 2022, 07:38:18 pm
content: Came across one of the above and it's chinese crap as expected - some 25 degC off when compared with a K-type on a Fluke (and which showed the Hakko FX-888D to be only about 5degC different).Looking at the board I see a missing VR1 which I imagine might just allow some adjustment. It's stated as 1K.However, there's a missing R10 also which is required - anyone fiddled with this to make it work?

author: magic
author_rank: Super Contributor
timestamp: September 20, 2022, 07:33:20 am
content: This board looks similar to the ubiquitous TM-902C type-K thermometer. I believe they are calibrated digitally, that's what the test points appear to be for. No idea if anyone has ever figured out how they work.TM-902C tend to be fairly accurate, typically ±1°C and I don't think I have seen one worse than 2°C off.Q1 and a few resistors are for cold junction compensation and the pot may be related to tweaking that.Speaking of cold junction, are the red/black K+/K- wires a proper thermocouple or ordinary copper?One of them ought to be magnetic if they are type-K thermocouple.editInfo on the other meter, maybe you will find something useful there.https://www.eevblog.com/forum/reviews/tm902c-digital-thermometer-info/https://www.eevblog.com/forum/testgear/tm-902c-cheapest-dedicated-k-type-thermocouple-thermometer-review/https://www.eevblog.com/forum/testgear/tm902c-quality-and-accuracy/If nothing else, it might be possible to transplant the board from a good TM-902C or to move the actual thermometer part to a small box with a thermocouple cable coming out of it for connection to any standard meter.

author: 6SN7WGTB
author_rank: Regular Contributor
timestamp: September 20, 2022, 10:38:48 am
content: Thanks for the links.Yes, it would appear that the supplied thermocouples may be K type as one side is magnetic.Attaching a proper Fluke K-type to the unit yields exactly the same error of about 20 degC below what the Hakko and Fluke say (which are within 5degC of each other).Interesting comments about the cold side, or lack of, or integration thereof. Which might render any attempt to 'calibrate' a waste of time.However, it's junk so I will add a pot and guess some resistors and see what I can do.
Adding waveform onto PLC - Page 1
Forum section: electronics / projects

author: eduf
author_rank: Newbie
timestamp: November 21, 2019, 12:39:44 pm
content: Hello everyone,This is my first topic here, so I hope to be done everything well.I am testing a PLC (Power-line communication) transceiver operating onto a 12V power line and in order to assure it is according to protocol specifications some testing steps defined in the specs must followed.The test of the receiver defines that the PER (packet error rate) must not exceed X% when the swept carrier waveform is received in the presence of a constant carrier interfering signal occupying a range producing a SINR (signal-to-interfering noise ratio) of 3.0 dB.Trying to be succinct what I have to do is to find a way to add this waveform onto the power-line.The frequency I chose to add was 120KHz.I first tried simply putting both signals in parallel, but as my signal generator has a limit of 10V it not surprisingly showed a message of voltage overload on output connector.Then I tried to use a clamper circuit assuming the PLC signal is majority DC, then noise would be the AC part. The circuit I used was a simple clamping with diode as shown in the following picture:The problem is that the waveform that after the clamping the waveform generated by the generator is been attenuated as you can see below. These are images from my scope. I kept the channel 1 in DC coupling mode then the 12V DC can be visualized.PLC waveform:Signal generator waveform - 120kHz 1Vpp:Waveform after clamper circuit – PLC and waveform 120kHz 1Vpp:Zoom at waveform, you can see it is been attenuated:Waveform after clamper circuit – PLC and waveform 120kHz 7Vpp:Zoom at waveform:Could you please give me suggestions or correct me if I am doing anything wrong?Is this method the one you would recommend me in order to add the PLC and sine waveforms?
Addressable digital RGB LEDs. - Page 1
Forum section: electronics / projects

author: luiHS
author_rank: Frequent Contributor
timestamp: November 17, 2019, 12:29:18 pm
content: Hi.Some time ago I made some designs with digital LEDs, specifically with WS2811 and APA102 5050 and 2020.Today, I see that there are many new references of digital LEDs, and some like the APA102 are no longer manufactured, or at least those they offer are not original, but the SK9822 with worse performance.I have been looking for information, but I am confused by the variety of new references and the features offered by each of them. For now I am documenting using the NewStar website as a reference, I think they are manufacturers, and offer several series of digital LEDs NS, SK, WS.http://ledstrip-china.com/products.asp?classid=122For now I choose to use APA107 or NS107. What I want in any case is that they are digital LEDs with Data and Clock signals, I don't want to use those LEDs controlled with a single wire because they require more complicated programming.I also read some time ago that there are some digital LEDs, which work so that if one LED fails, the rest still works, this interests me a lot, as long as I don't complicate the PCB design with more tracks.What experience do you have with digital LEDs, any recommendations?Regards
Addressable RGB LEDs (HD107S) as PCB indicators (lightpipe and other factors)? - Page 1
Forum section: electronics / projects

author: kreyszig
author_rank: Regular Contributor
timestamp: February 24, 2023, 03:30:09 am
content: Hi,I am thinking of using addressable RGB LEDs (HD107S or HD108) as configurable PCB indicators. They are mostly available in 5050 size, but they are also available in 2020, and rarely in 3535. 3535 would be my favorite choice, but it seems difficult to get a hold of them. The 5050 size seems a bad choice for compatibility with light pipes. So size 2020 is the remaining option.Is it a bad idea to use a light pipe with a 3.5 mm lens (e.g. 515-1020Fhttps://s3-us-west-2.amazonaws.com/catsy.557/Lightpipe_Selector_Guide_D.pdf) with a smaller LED?Other than fact that they are RGB, I like how easily these can be driven with any external buffer driver or current source, so they seem like a natural choice as indicators. What do you think?Thanks!

author: kreyszig
author_rank: Regular Contributor
timestamp: February 24, 2023, 04:49:01 am
content: Maybe thesehttps://www.mouser.com/datasheet/2/50/PLW5_XXX-3001513.pdfwould allow me to stick to the more widely available 5050 version (the HD108 seem to be only available in 5050)?

author: tooki
author_rank: Super Contributor
timestamp: February 26, 2023, 11:24:55 am
content: Using a smaller LED is no problem. If anything it’s desirable because it gives you more tolerance for positioning inaccuracy. What you do want, as much as practical, is to minimize the gap between the light pipe and LED. Like… you want a half mm or so for positioning tolerance, but beyond that, the larger the gap, the more light can exit laterally and illuminate other segments.I recently used the panel-press-in light pipes for the first time. Worked great, but to have them spaced closely as I did, I did find it necessary to prevent optical crosstalk by slipping black heat-shrink tubing over the pipes after insertion. (I then used a fine hot air nozzle to ever so slightly shrink the tube right next to the panel. (Heating it at the open/PCB end would cause the tube to shrink over the end of the light pipe, which I didn’t want.)

author: kreyszig
author_rank: Regular Contributor
timestamp: March 03, 2023, 01:25:11 pm
content: Thank you, it makes sense
Ademco SMS Gateway V2 Build Pics - Page 1
Forum section: electronics / projects

author: ludzinc
author_rank: Unknown
timestamp: July 01, 2014, 04:41:04 am
content: As the title suggests - some pics of my latest build.http://ludzinc.blogspot.com.au/2014/06/more-on-alarm-panel-interfacing.htmlI can't believe it's been more than a year since I started this projectBut now it comes with configuration software too!
ADF4360-8 PLL-VCO - Page 1
Forum section: electronics / projects

author: salviador
author_rank: Regular Contributor
timestamp: May 23, 2016, 08:19:05 am
content: Hi,I want build simple radio-microphone at band ~235.7Mhz.I see this IC from analog device.ADF4360-8 , have all, VCO, PLLBut my question is, How to modulate the carrier in FM ?

author: rs20
author_rank: Super Contributor
timestamp: May 23, 2016, 08:27:49 am
content: I'm not sure that chip is suitable? In principle, you could couple your modulating signal into Vtune, but I think the PLL is going to get very upset and confused when it sees that the phase of the LO is totally out of whack with the REF clk.I could very well be wrong.

author: babysitter
author_rank: Frequent Contributor
timestamp: May 23, 2016, 08:38:46 am
content: Better don't do it ar all - I guess someone who has permission to use that range in his designs will also be able to do FM.(The german frequency directory says military radio services only. As europe has a reasonable harmonisation going, this range will not be available to anyone else somewhere else in italy.)
Adhesive for IDC connectors? - Page 1
Forum section: electronics / projects

author: daqq
author_rank: Super Contributor
timestamp: August 21, 2019, 06:18:26 am
content: Hi guys,I need to vibration proof (or maybe shock proof) a device that uses several IDC connectors with flat cables ( similar to this:https://uk.farnell.com/multicomp/mc-254-10-00-00-idc/connector-rcpt-10pos-2row-2-54mm/dp/2843495), mated into the PCB through a classic counterpart (similar to:https://uk.farnell.com/hirose-hrs/hif3fc-20pa-2-54ds-71/connector-header-20pos-2row-2/dp/2724804).My question is, what would you recommend to keep them in? Something like the adhesive used on tall electrolytic capacitors (https://www.robotroom.com/Parts/Samsung-monitor-capacitors/Healthy-capacitor-with-flat-clean-top-and-flush-to-board.jpg)? Ideally something stocked at farnell that can be applied with a syringe (parts of the device are really really hard to get into with anything big.Thanks,David

author: voltsandjolts
author_rank: Unknown
timestamp: August 21, 2019, 07:15:50 am
content: Expensive but it works nicely:Dow Corning 3145https://uk.farnell.com/537007

author: tautech
author_rank: Super Contributor
timestamp: August 21, 2019, 07:33:06 am
content: Look for fabric tapes.These are commonly used to keep ribbon cables secure in test equipment.Example:https://nz.rs-online.com/web/p/cloth-tapes/9054214/

author: David Hess
author_rank: Super Contributor
timestamp: August 21, 2019, 02:11:16 pm
content: Use a latched IDC header.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 21, 2019, 02:20:02 pm
content: Th latched idc is okay, but sometimes you need to lock the latchs too, small dab of sillicone on them ..
ADI JTAG EMU Pin - Page 1
Forum section: electronics / projects

author: blueskull
author_rank: Unknown
timestamp: November 10, 2015, 01:13:22 am
content: Hi,I am in the design process of a test jig for my ADSP-BF706 based device. According to the debugger's manual (ADSZ-ICE1000), it says the indicator LED will report an error if EMU is not correctly asserted, and according to their JTAG manual (EE-68), EMU should be connected to the DSP's EMU pin. In my case, BF706 does NOT have an EMU pin. How should I connect this pin? Left floating? Ground? Or pull up?
Adj Power Supply PCB suggestions - Page 1
Forum section: electronics / projects

author: IamSynthetiC
author_rank: Regular Contributor
timestamp: June 08, 2020, 10:51:57 pm
content: Greetings,I have a need for a small adjustable power supply to power my circuits that are not on the bench (where the lab power supply sits), or simply require a second rail. And since power supplies fascinate me, i though of designing and building my own. Unfortunately, i have no expirience designing, nor building power supplies, hence i've come to the expertsI wanted this supply to haveHigh EfficiencyLow NoiseSmall FootprintPowerd by 12V wall adapter or an 18V drill batteryi have selected some parts that seem to fit my needs, and i followed their datasheets as best as i could. I will attach my design bellow.This design is definetly not final as it lacks safety features, and its dimensions will probably change to fit into an enclosureSo, have i done something wrong? is there something that can be improved ? is there something i should note ?Thanks for your time and have a good day*Edit : i attach the design as an image aswell :

author: PlasmaArcEng
author_rank: Newbie
timestamp: June 11, 2020, 03:01:26 am
content: Without looking too deeply into it, the MIC29303 pin 1 is a FLAG, a sinking (active low) output for an error condition, so the led attached has to be reversed and attached to the +ve rail. I am sure the resistors you have for the LEDs are place holders as 100K wont give you any appreciable output.

author: IamSynthetiC
author_rank: Regular Contributor
timestamp: June 12, 2020, 08:55:10 am
content: Wow, nice catch. I must have missed this about 20 times so far. Thanks.other than that, i think i'll order the parts and pcb and make one or two.

author: bin_liu
author_rank: Contributor
timestamp: June 13, 2020, 03:48:51 am
content: The noise of the switching power supply is not small.

author: IamSynthetiC
author_rank: Regular Contributor
timestamp: June 13, 2020, 09:56:48 pm
content: I put this together very hastefully, but still. I though in the datasheet i had seen the words "low noise" but no. Doesnt even provide a noise graph.Thank you kind sir, for saving me some troubles, aswell as from my own stupidity and self.Do you have any switching supplies suggestions ? Any you have worked with ?I'll probably select one with a higher frequency for now.Thanks again.

author: Vovk_Z
author_rank: Super Contributor
timestamp: June 14, 2020, 06:57:23 am
content: Properly designed dc-dc won't make much noise (until you need really ultra low noise power supply).It is an interesting task to make it quiet.

author: ocset
author_rank: Super Contributor
timestamp: June 14, 2020, 01:11:56 pm
content: Here is an adjustable smps in the free ltspice simulator.The idea is you use an external error amp and then adjust its reference depending on what vout you want.
Adjacent Power Supplies - Crosstalk - Page 1
Forum section: electronics / projects

author: vidarr
author_rank: Frequent Contributor
timestamp: May 06, 2025, 09:48:54 pm
content: Is it OK to put power supplies next to each other? I was reading about coils and crosstalk and realized I have a couple of coils adjacent to each other.In the attached photo you can see there is a 48V PSU (top right), below that to the right is a 12V PSU, to the left of that is a 5V PSU.The 48V PSU has that inductor coil right next to the two, smaller PSUs. This maybe is a problem?Thank You!(The project is a cheap little amplifier we can use outside on the ocean.)edit: the pic got rotated somehow, so the 48V PSU in now to the bottom right.

author: incf
author_rank: Frequent Contributor
timestamp: May 06, 2025, 10:03:38 pm
content: There is only one way to know - measurement. I personally don't think there is very much potential for an issue so long as "good practices" are followed (whatever those may be).

author: vidarr
author_rank: Frequent Contributor
timestamp: May 06, 2025, 10:41:53 pm
content: Somewhere else, it was stated that a "good practice" was to measure the coil and multiply by 2(?) to get a distance from one coil to another. It said if the coil is 10mm, then the next coil should be 15-20mm distance from that coil.I wish I had the equipment to measure magnetic fields, crosstalk, etc. I only have a simple DMM.Thank You!

author: incf
author_rank: Frequent Contributor
timestamp: May 06, 2025, 11:46:56 pm
content: build it and see if it works - that's how you find out without test equipment

author: Poroit
author_rank: Frequent Contributor
timestamp: May 07, 2025, 09:24:41 am
content: G'day vidarr,I have used multiple Meanwell SMPS's in Instrumentation enclosures without any issues.What type of signal are you measuring and does your DAU have Isolated inputs?

author: vidarr
author_rank: Frequent Contributor
timestamp: May 07, 2025, 02:02:05 pm
content: Quote from: Poroit on May 07, 2025, 09:24:41 amI don't know what that means.But, it is good to know you didn't have any problems with PSUs next to each other. I am powering this up later today.Thanks!
ADjust voltage with DAC? - Page 1
Forum section: electronics / projects

author: echen1024
author_rank: Super Contributor
timestamp: September 22, 2013, 11:01:03 pm
content: So, I have the circuit below:And I would like to know how to implement a DAC, such as the MSp4725, to adjust the voltage. I know that the LM317 tries to form a 1.25v reference between the Voutand the ADJ pin, but how would I emulate this digitally. Also, as far as I know, I would need an Op=Amp to amplify the signal of the DAC. Circuit diagrams are very much appreciated, as well as any other helpCheers,Eric

author: dannyf
author_rank: Super Contributor
timestamp: September 22, 2013, 11:48:53 pm
content: Sum the DAC output + PS output to the ADJ pin: increasing the DAC output will lower the output voltage, and vice versa.

author: kizzap
author_rank: Unknown
timestamp: September 23, 2013, 01:48:26 am
content: Just use an op-amp at the adj pin of the LM 317, with the op-amp out to the adj pin, the voltage out to the inverting pin, and the wanted voltage reference fed into the non-inverting pin(+). The op-amp will do the job of offsetting the 1.25V (or whatever it will be) to drive the 317 correctly.-kizzap

author: echen1024
author_rank: Super Contributor
timestamp: September 23, 2013, 02:03:36 am
content: Ok. What type of Op-Amp would I need. A precision, speed, etc...

author: Bored@Work
author_rank: Super Contributor
timestamp: September 23, 2013, 04:48:08 am
content: Quote from: echen1024 on September 23, 2013, 02:03:36 amThe LM317 doesn't care if its adjust pin is driven directly by a DAC or an OpAmp. It cares that whatever it drives can sink (not source) the current established by the resistor between out and adjust.If the common 120 Ohm are used that would be 10 mA. And sinking 10 mA is a problem. One way to solve this is to reduce the current. The price to pay for this is that the minimum LM317 current needs to be established in another way, an additional load on the output. Another one would be to drive the adjust pin with a transistor, introducing more non-linearity.

author: kizzap
author_rank: Unknown
timestamp: September 23, 2013, 05:36:26 am
content: Quote from: Bored@Work on September 23, 2013, 04:48:08 amAs Bored@Work said, it doesn't really matter too much as to the speed, as ideally the power supply will not need to react too much to changes (unless of course you have a Constant Current mode tied into the amplifier as well). The more important thing that you will need to consider is that you will need to power the op-amp from a voltage source that will be able to go above the required output voltage, so that the upper extent will need to go to Vout -1.25 at a minimum, you should be able to simply tie this to the input voltage of the LM317, and if you want to be able to drive the voltage down to zero volts, you will need to provide a negative rail. And one final trick you will have to worry about is the voltage differential between the rails, most Op-amps don't have that great of a voltage range. I'm thinking something like one of the TL07x or TL08x series might be ok.-kizzap
Adjustable analog filter - Page 1
Forum section: electronics / projects

author: m98
author_rank: Frequent Contributor
timestamp: August 31, 2015, 10:17:36 pm
content: Hi,I need a notch filter for audio signals at line level. It should have an adjustable center frequency of 800-8000 Hz with 1 Hz steps.Thought that I could build the filter with discrete components and adjust it with digital potentiometers, but that seems to get big, costly and difficult to calibrate.Could a switched capacitor filter ic be an alternative? I've found thisapplication note, featuring the MAX7410. But it only has a Q of 1.7, which is too low. I need something about 10.Any suggestions?Thanks for your helpm98

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 01, 2015, 12:36:35 am
content: If you need it so precisely, you should probably just do it with a DSP. Switched capacitor might be okay (if you don't mind that it's Maxim), but mind the other aspects of them as well (reduced high frequency bandwidth, switching noise).If you don't need exact steps, but rather a tolerance range is acceptable, then a number of methods might be applicable. See also OTA filter circuits.Tim

author: Circlotron
author_rank: Super Contributor
timestamp: September 01, 2015, 03:07:15 am
content: Do you need to do the filtering in real time? If not, maybe record it then play back and notch it with Audacity or something similar.

author: m98
author_rank: Frequent Contributor
timestamp: September 01, 2015, 12:25:37 pm
content: Yes, filtering needs to be real-time. Didn't want to use a DSP, as I don't have any experience with them. Also that would be a bit overkill.After reading some application notes and datasheets of switched capacitor ics, I found that the "newer" generations have only a negligible clock feedthrough and switching noise. I think that the LTC1067 fits my application.
Adjustable constant current with the TLC59711 PWM LED Driver - Page 1
Forum section: electronics / projects

author: mdszy
author_rank: Unknown
timestamp: May 25, 2017, 10:11:57 pm
content: I'm working on a project that requires an array of RGB LEDs and the total current consumption has to change depending on what is powering it. I'm using the TLC59711 and designed a way to change the constant current setting by adding a single MOSFET and resistor. I'm pretty happy with how it works, and hopefully it'll be of use to someone else!
Adjustable current on buck-boost IC designed for adjustable voltage  - Page 1
Forum section: electronics / projects

author: Obi_Kwiet
author_rank: Regular Contributor
timestamp: March 13, 2012, 08:37:07 pm
content: I am trying to design a buck boost current regular that could be used to drive LEDs or laser diodes from a Li-I battery. I've been looking over datasheets for several days, and I really like theTI TPS63020. The trouble is that it's designed to regulate voltage, and I need fairly precise, adjustable current regulation. Looking at the datasheet, it seems like I should be able to modify the voltage divider on the FB pin and use a current sense resistor and an amplifier to achieve current regulation. I was considering theNational Semiconductor LMP8645.However, I'm worried about controls issues. I've on had one fairly poor control systems class, and I'm trying to teach myself power electronics, so I don't really have a feel for whether this approach is going to introduce instability into the control loop. I just know that I really don't know what I'm doing in this respect, and I'm not really sure how to know other than to brute force my way through some power electronic and control systems textbooks. I considered this, but it is usually a recursive process that kills the project. I would be grateful for some insight or at least a hint in the right direction.Note that in addition to getting a 2A output current between ~2 and ~6V, I really want to be able to get the whole package as small as possible to use in flashlights. I want to get the size of the package as close to 200mm^2 as possible, and smaller if I can.
adjustable HV power supply modules - Page 1
Forum section: electronics / projects

author: phenol
author_rank: Regular Contributor
timestamp: April 20, 2018, 04:57:11 am
content: Can anyone recommend a reputable source/brand (except Keysighht and Keithley) of ac/dc regulated power supply bricks/rackmount/etc for integration. It has to deliver 0-200V/0.5-1A and for another project--1000V/0.3-0.5A. I don't care about connectivity, etc. It will be set and forget during installation and only work at one fixed voltage within its operating range. For the first prototype i made my own fixed boost converter as an exercise, but (lessons learned) i don't want to go that route again...

author: ikrase
author_rank: Regular Contributor
timestamp: April 20, 2018, 06:05:36 am
content: That is quite a bit of current. This kind of thing is generally... expensive.Spellman and Glassman come to mind. With only 1000 volts, you have more options.

author: oldway
author_rank: Super Contributor
timestamp: April 20, 2018, 06:42:44 am
content: http://www.fug-elektronik.de/en/products.html

author: phenol
author_rank: Regular Contributor
timestamp: April 20, 2018, 11:27:17 am
content: Thanks for the suggestions. The actual average current drawn from the PSU is going to stay in the sub-100mA range, but if underpowered, i'm afraid it could go into hiccup mode or whatever during power up when it has to charge the bulk capacitors the load has.

author: BravoV
author_rank: Super Contributor
timestamp: April 20, 2018, 11:32:39 am
content: Quote from: phenol on April 20, 2018, 04:57:11 amA budget or even ballpark figure if you're shy, will make this thread more meaningful, as people here just love to bombard you with various products they had in mind without concerning the depth of your pocket.As olde says ... Money Talks ...

author: Cerebus
author_rank: Super Contributor
timestamp: April 20, 2018, 12:15:57 pm
content: UltraVolt:https://www.advanced-energy.com/en/UltraVolt_Power.html

author: phenol
author_rank: Regular Contributor
timestamp: April 20, 2018, 01:00:45 pm
content: Something like this would fit the bill, technically speaking:https://www.advanced-energy.com/en/CSeries.htmlor like this:https://www.spellmanhv.com/en/Products/UMMy budget is open-ended; if i need it, i get it...well, kind of. It's all a matter of how convincing one is in front of the benefactors...Quote from: BravoV on April 20, 2018, 11:32:39 am
Adjustable Inverting Buck-Boost (IBB) through current source/sink DAC - Page 1
Forum section: electronics / projects

author: t8y6lp64
author_rank: Newbie
timestamp: April 17, 2025, 09:14:20 am
content: I am trying to design a circuit with an adjustable Inverting Buck-Boost (IBB) using the LM43601. The IBB takes +5 V as input and can produce any voltage in-between -5 V and -24 V. The output voltage should be adjustable through a sink/source current DAC, namely the DS4432. Now the question arises if this is possible, and if so, how should the level shifting look like for the signal between DAC and the FB pin of the IBB?For reference, I have attached the schematic of the IBB. TheFB_NEGlabel shows where the current shall get injected from the DAC.

author: moffy
author_rank: Super Contributor
timestamp: April 17, 2025, 10:49:45 am
content: I assume that the DAC is on the +5V to 0V side, as well as its control signal, you could use the DAC to drive a PNP current source where the collector of the PNP transistor feeds into the FB_NEG node, you might want a diode in series with it. The more current it feeds in the less the set output voltage, and set up the resistors R11 and R12 for maximum negative output voltage so that when the current source is off you get maximum negative i.e. -24V.

author: t8y6lp64
author_rank: Newbie
timestamp: April 17, 2025, 11:22:12 am
content: Thanks for your answer. This is indeed a viable solution, however doing that I would lose half the resolution of the DAC as I would only use it in source mode, right? To actually use the full range, I would require a bidirectional level shifter, or am I making a mistake here?

author: mtwieg
author_rank: Frequent Contributor
timestamp: April 17, 2025, 11:43:30 am
content: If you need to preserve the bipolar output, I'd recommend referencing the DS4432 to Vout, and translating the logic signals instead. Should be much more straightforward than translating a bidirectional current source.

author: moffy
author_rank: Super Contributor
timestamp: April 17, 2025, 11:48:45 am
content: Quote from: t8y6lp64 on April 17, 2025, 11:22:12 amAll you would need is a standard 8 bit DAC and an opamp and transistor, might be worthwhile.
Adjustable Slewrate - Page 1
Forum section: electronics / projects

author: lukaev3
author_rank: Newbie
timestamp: November 14, 2024, 12:24:05 pm
content: Hello,I have the following issue I cannot resolve. My output signal is from a DAC; it swings between -5V and 5V, outputting a square wave with variable duty cycle, Vmin, and Vmax.Now to my question:How can I have an adjustable slew rate on the rising and falling edges (it can be the same for both falling and rising)?Example: When transitioning from 1V to 3V and back, the slew rate/ramp should be adjustable. The slew rate is preferably set by a voltage or current.The slew rate should be a maximum of 1V/μs and a minimum of 1V/ms.I have thought about using integrators, but they don't stop at my desired value.Additionally, I also thought about transconductance amps, but they would have a droop at the end of the slope, right?Another way would be a diode bridge, but I need to vary the current sink/source with one control signal, which is not that easy as it seems to me.Thanks in advance!

author: MasterT
author_rank: Frequent Contributor
timestamp: November 14, 2024, 01:08:24 pm
content: https://www.ti.com/lit/an/sboa218b/sboa218b.pdf?ts=1731566730893https://www.ti.com/lit/ug/tidu026/tidu026.pdf?ts=1731542141599To make it adjustable use digital pot.

author: David Hess
author_rank: Super Contributor
timestamp: November 14, 2024, 02:40:57 pm
content: Quote from: lukaev3 on November 14, 2024, 12:24:05 pmDo you only have one analog control signal available?

author: lukaev3
author_rank: Newbie
timestamp: November 14, 2024, 02:57:54 pm
content: I only have one DAC for my analog set point for now, but it would not be an issue to have a second...As for the slewrate setting i was thinking of also using a 8bit dac so its not an issue

author: PCB.Wiz
author_rank: Super Contributor
timestamp: November 15, 2024, 01:30:49 am
content: Quote from: lukaev3 on November 14, 2024, 12:24:05 pmI think an OTA could work quite well, you just need to power it with enough voltage it stays in the linear range. (eg +/-6V or more)The OTA then works like a symmetric current limiter, so 1mA of bias and 1nF is 1V/us and 1uA of bias puts you in 1V/ms ballpark.If you get a dual OTA, maybe you can use one channel to measure the current, and leverage the tracking ?
Adjustable Step up regulator - Page 1
Forum section: electronics / projects

author: Aodhan145
author_rank: Frequent Contributor
timestamp: May 09, 2015, 09:24:06 am
content: Hi, I found this 150W Step up converter on Aliexpress, Would anybody be able to look it over to see if it is going to explode?http://www.aliexpress.com/item/150W-DC-DC-Boost-Converter-10-32V-to-12-35V-6A-Step-Up-Voltage-Charger-Power/32260792513.htmlThanks in advance.

author: kjs
author_rank: Regular Contributor
timestamp: May 09, 2015, 09:47:17 am
content: with just the 3 pictures it's impossible to judge anything. However, at an efficiency of 90% or less (the 94% are for sure optimistic) and 150W Pout the heatsinks looks a bit small. If you need half the power (75W) it most likely will do the job.

author: Aodhan145
author_rank: Frequent Contributor
timestamp: May 09, 2015, 11:03:56 am
content: Thanks, I will look for a beefier module then.
adjustable thermal cut-out - Page 1
Forum section: electronics / projects

author: blackjames
author_rank: Regular Contributor
timestamp: October 08, 2012, 08:59:31 pm
content: hi guysim currently designing a low voltage thermostat, with a latching circuit to act as a thermal cutout. it was originally designed as an over temperature protection for my rc battery charger. i plan to suggest my design to sparkfun electronics. i thought about one with a switching regulator so you could run it from 24 volts aswell as 12 volts dc. its a comparator based one, but maybe a digital one with a micro might be better. please give me some suggestions for improvements.