hybridfree/eevblog-posts huggingface dataset:
Acorn Stairlift Remote Problem - Page 1
Forum section: electronics / projects

author: Seekonk
author_rank: Super Contributor
timestamp: July 18, 2015, 12:24:27 pm
content: I just installed an Acorn 120 stair lift at my parents home. The problem is there is another Acorn stair lift nearby. Both lift remotes have the same code and both operate at the same time. Opened the remote battery cover and there is a dip switch, 1 is up and 2 is down. Simple enough, I make them both up and neither stair lift responds. This should be simple, just remove the cover on the lift and change the code on the control board.PROBLEM: There are no dip switches, jumpers or anything on the control board. Just header pins to program the micros. There are two jumper wire loops that could be cut on one of the connectors. It has to be something simple. Don't think they want installers going in and changing code. I hesitate to just cut the wires and experiment. I'm here with nothing and don't have anything to solder the wires back together. Two lifts in the same house is fairly common. Thought there ought to be a video and checked youtube, but nothing. Any installers out there with a solution?

author: m98
author_rank: Frequent Contributor
timestamp: July 18, 2015, 01:09:20 pm
content: Could you make a picture of the control board? But generally cutting wires is not the way of configuring such a device, maybe there's a special programming device. Why don't you ask the Acorn support?

author: wagon
author_rank: Frequent Contributor
timestamp: July 18, 2015, 01:20:15 pm
content: I believe the Acorn stuff is pretty well supported. I would ring or email them with your problem.

author: amyk
author_rank: Super Contributor
timestamp: July 18, 2015, 01:25:13 pm
content: Are these RF remotes? One of themanualsI could find suggests these are IR, so it could be a matter of the remotes not being directional enough.

author: Seekonk
author_rank: Super Contributor
timestamp: July 18, 2015, 02:01:36 pm
content: "could be a matter of the remotes not being directional enough."That is called IR bouncing off walls. Not a solution. Not painting everything flat black.
acoustic in audacity  - Page 1
Forum section: electronics / projects

author: harrysmith
author_rank: Contributor
timestamp: January 29, 2021, 11:22:16 am
content: Hi everyoneI want to do a small project (like a report) about the acoustics. and realize it on audacity or matlab I want to hear from you. because yes I am not precise. basically it's about acoustics .Thanks

author: jonpaul
author_rank: Super Contributor
timestamp: January 29, 2021, 02:59:20 pm
content: Impossible to get any answers till you give us more specifics: EgHigh school project? Advanced degree paper? Magazine article? Just to learn?Use Audacity (not suitable) or Matlab to model room echoes?Jon

author: IDEngineer
author_rank: Super Contributor
timestamp: January 29, 2021, 07:48:17 pm
content: I took an entire course on "Physics of Acoustics" decades ago, and the topic hasn't gotten simpler with the passage of time. You need to carefully specify on which sub-sub-topic of this discipline your "small project" will focus.
Acoustic signal Amplifier+Filter - Page 1
Forum section: electronics / projects

author: RoyFokker
author_rank: Newbie
timestamp: May 25, 2018, 01:00:42 am
content: xd

author: Marco
author_rank: Super Contributor
timestamp: May 25, 2018, 04:13:21 am
content: How are you measuring the low frequency noise and what kind of levels are you seeing?

author: StillTrying
author_rank: Super Contributor
timestamp: May 25, 2018, 11:08:55 am
content: Have you checked that the output of the first stage is near 0V. The input bias currents of the AD797 are too high to use 20M for the biasing, try 1M, same as the feedback resistor - for now. They'll still be too high, but should give some idea whether or not the X100 gain is needed.

author: David Hess
author_rank: Super Contributor
timestamp: May 25, 2018, 06:19:03 pm
content: In both cases the input bias current and input current noise is too high for good results. For good low frequency performance with a piezoelectric transducer, a low input bias current amplifier is required.

author: Marco
author_rank: Super Contributor
timestamp: May 25, 2018, 10:30:56 pm
content: Worst case output offset for the instrumentation amp from offset current is 35e-9*1e6*20, that's not going to make it clip.Not that it's relevant ... you are using BJT based amplifiers on an extremely high impedance source, don't do that. Use an AD8220 or something.

author: StillTrying
author_rank: Super Contributor
timestamp: May 25, 2018, 11:33:56 pm
content: On the AD797 one, C7 16uF is the wrong way round.

author: JS
author_rank: Frequent Contributor
timestamp: May 30, 2018, 02:50:33 am
content: Quote from: RoyFokker on May 29, 2018, 01:02:36 pmAlso C6 and quite a bit more obvious.JS
Acoustically detecting a stalled induction motor? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: July 06, 2020, 07:19:17 am
content: What kind of specs or features should I look for when choosing a non-invasive sound/vibration sensor that can tell the difference between a 50Hz AC induction motor that is stalled vs running normally. A stalled motor typically makes a loud humming sound with lots of harmonics as shown in this video

author: Berni
author_rank: Super Contributor
timestamp: July 06, 2020, 07:36:46 am
content: You could certainly attach a piezo contact microphone to the case, run that trough a 100Hz filter, peak detector and comparator.But a more reliable method is clamping a current transformer around one of the wires and sensing the current. It always draws an abnormally large current when stalled.While you are at it you might as well also connect that sensor to a relay that disconnects power from the motor. I'm guessing you are asking this because you have a motor that is likely to stall, and in that case it would be wise to have a automatic system that kills power to it since leaving it stalled for any significant length of time is sure to destroy its windings to charcoal. But a carefully chosen value slow blow circuit breaker should do the job by tripping when experiencing a stall current for too long. A circuit breaker is much cheaper than a brand new motor

author: phil from seattle
author_rank: Super Contributor
timestamp: July 06, 2020, 02:25:10 pm
content: My first thought is an FFT. Sample running and stalled motors and look for the difference. Lack of consistency between different motors might be an issue. You might discover common frequencies among stalled motors that you could look for.But, wouldn't a clamp on current meter be simpler? The non-invasive part might be a bit harder to attain with that.

author: ejeffrey
author_rank: Super Contributor
timestamp: July 06, 2020, 07:07:33 pm
content: If you do an FFT with a long enough sample time you should be able to see the 50 Hz line peak plus the 50 Hz - slip rate mechanical frequency of a running motor. A stalled motor will only have the 50 Hz electrical hum. Depending on slip at minimum load you might need several seconds of data to see this clearly so you would have to determine if that was fast enough for your application. You could also look at 25 Hz which will be the rotational frequency of most induction motors but not have a large contribution on a stalled motor unless you are getting asymmetric saturation.If at all possible I would say do either a phase current monitor or a shaft sensor.
Acquisition Module : First prototype inside:) - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: July 12, 2013, 10:46:34 pm
content: Hi there:)Remember this thread over here?https://www.eevblog.com/forum/projects/new-project-analog-acquisition-board/Probably notHere is the short summery:The Acquisition Module is an addon Module for any Dev- Board that need high speed ADC but doesn't have any(like the most of them). Especially high speed FPGA boards sometimes need a high speed analog frontend for data acquisition. Like my Altera DE1 FPGA.So i started to design my own acquisition moduleHere are specs for this prototype:3xADC08200 =200MSPS, 8bit ( will be overclocked to 250MSPS)3xDAC5311 = one DAC for each ADC. It is generating the Vref-Top, the reference voltage for ADC. So if your signal has max. Value of 1.5 V, you can set the reference voltage to use the whole 8 Bit resolution.The main CLK-Source is Fox electronics 250 Mhz Oscillator. Its is very expensive! ( 80 € or so) But considering i got it as sample...The data Acquisition /Preprocessing and so on will be done by Altera CPLD MAXII. It also controls ADC/DAC , and generate CLK for ADC ( so you can choose from 250,125,62.5 and 31.25 Msps in order o spare some energy)You also have 7 Blue LEds to play with:PThe A-Module has ca. 48 GPIO so even if you assign all 3x8 bit channels , you will still have 24 GPIO for your special features;)Speaking of features, you can always upgrade the CPLD-Firmware to fit your project via JTAG. My Current Firmware takes about 300 LE, so you still have 270 free LE to play with.(or you write your own from scratch:) )The current firmware allows the user to change the configuration like samplerate, Vref's, switch ADC on/off via simple 2-Wire interface, it makes this module completely autonomous, so it can be used with any kind of Dev. Boards, even with arduino;)The PCB has 4 layers: Signal, GND, Vcc,Signal.Now, i am glad to show you my first prototype assembled last night.It has some FAILS like wrong footprint for voltage regulator ( not a big problem through) and i forgot 4 Vias for bypass caps....what a noob. But i could fix it with copper wire. Also my hand soldering it not the first class, but considering this is my first project and first PCB-Design in my life, i still consider it as success:))Now it is running a simple LED-Counter, the main Firmware is almost done and will be tested this weekend.

author: benemorius
author_rank: Regular Contributor
timestamp: July 13, 2013, 03:12:23 am
content: Nice job.Probably you can design out most or all of the tantalums. Most people avoid them unless there is absolutely no choice. Ceramics have come a long way.

author: Jebnor
author_rank: Regular Contributor
timestamp: July 13, 2013, 04:10:26 am
content: Very Nice.

author: PuterGeek
author_rank: Regular Contributor
timestamp: July 13, 2013, 08:26:56 pm
content: Especially nice for a first effort! I've seen much worse from seasoned 'professionals'!
Acrylic wire bender - power supply for multiwires - Page 1
Forum section: electronics / projects

author: madan
author_rank: Newbie
timestamp: August 08, 2021, 10:39:09 pm
content: Hi everybody,This is my first post here, I hope you don't mind that I start with a question. I have been a regular visitor here and learnt a lot!I'm designing an acrylic bender. I've made two benders before, but this time I need something more repeatable, adjustable and reliable.For the frame I'm going to use an aluminium v-slot extrusion. Because it is simple to make changes.Basically, the whole device will be a power supply connected to the nichrome wire. The wire gets hot and softens the acrylic sheet. The wire is connected to the spring as it expands with the temperature raising. There will be an under-reflector and upper-reflector. I am still thinking what parts to use for holding nichrome wire and how to connect it to a compression spring.The problem is that in order to achieve a higher radius of a bend I need to heat up a wider surface. That is why I need multiple wires - 3 under and 3 above the material.I've chosen power supply x 3https://ooznest.co.uk/product/350w-power-supply/I would use 1 power supply per 2 channels. Please let me know if that is a mistake.Before, I used this controllerhttps://www.amazon.co.uk/dp/B075FR2LBP?ref_=pe_27063361_487360311_302_E_DDE_dt_1But Can I use 6 of these for 6 channels? Or maybe 3 to control 2 channels with one? Should I use the step down converters instead?I'd be using from 1 to 6 channels depending on the thickness and type of the material.Oh and I assumed that 24V @ 7A per channel is enough for the wires. Resistance of the wire around 4 Ohms.Any suggestions are very welcome.Cheers,Daniel
ACS 712 current sensor - Page 1
Forum section: electronics / projects

author: jonwhite
author_rank: Contributor
timestamp: November 21, 2016, 08:49:12 pm
content: Hello I'd like to use this sensor and make a simple switch I'd like to measure the current t of a single phase and when it gets to say 200 ma output 5v wonder if anybody could point me in the right direction ie what if I component I could use that would do the jobMany thanks

author: Seekonk
author_rank: Super Contributor
timestamp: November 21, 2016, 09:24:31 pm
content: Single phase? Do you want to look at one side? Do you want average or peak? The output centers around 2.5V. A three terminal LM431 trips at 2.5V. Add a pot and you could easily look at one side of the waveform and look at the peak. A PNP transistor could then invert the signal. Or use a comparator, the 431 could be your reference.

author: jonwhite
author_rank: Contributor
timestamp: November 21, 2016, 09:52:09 pm
content: I want to measure an AC signel single phase and when that phase is lost trigger a 5v output

author: Seekonk
author_rank: Super Contributor
timestamp: November 21, 2016, 11:21:48 pm
content: Why 5V? Is this a micro? Does it have an A/D? Do I have to do all the work?

author: moffy
author_rank: Super Contributor
timestamp: November 21, 2016, 11:49:02 pm
content: The application circuits in the data sheet are quite suitable, if slightly modified. You just need a comparator after the rectified and filtered output to convert your signal from analogue to digital.

author: Seekonk
author_rank: Super Contributor
timestamp: November 22, 2016, 12:14:48 am
content: The output from a 712 in an ac application will be a low level ac signal. That could be amplified and rectified. Something as simple as running it directly into a logic input may be sufficient for go/no go application.I just got back to project that uses a 5A ACS712. At 200ma DC I only get 10 counts on a 10 bit A/D. Of that 4 counts are noise. And I've found these are drifty with temp. Maybe because these are cheap ebay clones. I think YOU would have difficulty using these in this application. You would be better off using a current transformer with multiple loops.
ACS712 and ESP8266 - Page 1
Forum section: electronics / projects

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 08, 2016, 09:15:32 am
content: Hi All,I want to use an ACS712 current sensor to verify that a device ( heater) is turned on with a nodemcu (ESP8266).It will be 1.5 kw so 6.5 A on 230 V. I will use 20 A ACS712 that is 100mV/A.The output of the ACS712 will thus be 2.5 V + 0.65V sinewave.This would be easy on an arduino, but the ADC pin of the ESP8266, from what I understand is only 1V range.I thus want to transform the output signal in a plain HIGH state for the ESP8266, and notuse the ADC. I just want to know if it is ON or OFF.After searching a little bit, I came with the following design. The final output is PR5.I made the simulation under multisim. A is in ON (2.5 V + 0.65V sine input) , B is OFF (2.5 V input).Please comment and criticise.
act as a LXI device - Page 1
Forum section: electronics / projects

author: e61_phil
author_rank: Frequent Contributor
timestamp: February 07, 2017, 11:57:05 am
content: Hi,I've build a high voltage test system which is based on a raspberry pi and python. Everything is working fine now. However, I would like to add LXI Device support. It would by nice if one can use my device like any other test-equipment via VISA and control it from Python, LabVIEW, Matlab or whatever..Does anyone know some descriptions or a project in which python acts as a LXI device (not host)?ThanksPhilipp

author: voltsandjolts
author_rank: Unknown
timestamp: February 07, 2017, 01:36:12 pm
content: Perhaps a barebones starting pointhere.Or maybe wrapthiscode in python bindings.

author: jbb
author_rank: Super Contributor
timestamp: February 07, 2017, 11:43:12 pm
content: Doing the full LXI is pretty hard. And there are several features you may not need (e.g. precise triggering, webserver to manually control/configure it). Just implementing SCPI over Ethernet might hit the mark for you.

author: e61_phil
author_rank: Frequent Contributor
timestamp: February 07, 2017, 11:49:47 pm
content: SCPI over ethernet will do the job. But it will be nice, if it will work via normal VISA commands.
Activate the design rules in Eagle layout - Page 1
Forum section: electronics / projects

author: rithi3
author_rank: Newbie
timestamp: December 17, 2012, 09:44:26 am
content: Plz tell me the option to stretch/clean up the traces with design rules like spacing,in Eagle layout. Thanks!!!!

author: hlavac
author_rank: Frequent Contributor
timestamp: December 17, 2012, 04:47:37 pm
content: You want to run DRC to find the spacing violations. But you will have to fix them yourself I'm afraid.
Active Bandpass Filter Output - Page 1
Forum section: electronics / projects

author: alihashemi
author_rank: Newbie
timestamp: August 25, 2015, 10:56:46 pm
content: Hi All:This may seem like a dumb question but here goes:I have a INA129 going to an OP481 which is used as a 4 stage bandpass filter. The output of the filter will be going into an ADC. Since the feedback elements of the filter are on the non-inverting terminal, does that OP481 act as a filter AND a buffer thus eliminating the need for a buffer prior to going into the ADC?Thanks in advance!Ali

author: retrolefty
author_rank: Super Contributor
timestamp: August 26, 2015, 01:12:29 am
content: Quote from: alihashemi on August 25, 2015, 10:56:46 pmThat most likely is the case. Most ADC have high input impedance that should not require a seperate driver/buffer.
Active clamp vs Two switch flyback - design effort and efficiency questions  - Page 1
Forum section: electronics / projects

author: Miyuki
author_rank: Frequent Contributor
timestamp: November 09, 2020, 12:18:05 pm
content: Hi folks,I want to discuss pros and cons of Active clamp vs Two switch flybacksTarget is 50-200W lightingActive clamp is much more popular today and at fixed load, it can operate in ZVS/ZCSBut two switch looks simpler to design and tend to have better reduced/light load efficiencyAnd even when I do a quick calculation of expected switching losses, it shows just about 1-2W of switching losses even with Si transistorsIs there any reason why active clamps are commonly preferred over two switch?Is it a noise issue? As ACF can switch slowly, but two switch must turn off really fast and mains capacitor has suddenly reversed current flow.

author: TimNJ
author_rank: Super Contributor
timestamp: November 10, 2020, 04:26:54 pm
content: I have used neither, so this is just high level commentary based on reading through app notes and datasheets. Both TI and ON Semi have ACF controllers, UCC2870 and NCP1568, respectively. We considered them for a new design, but determined that normal QR flyback was sufficient for our power density and cost requirements. ACF appears to need some extra attention to the control loop at light load. I don't know if this is also the case for two-switch flyback, but I don't think so.From what I can tell: ACF has advantage for EMI and efficiency, as it can almost always get very close to ZVS, whereas two-switch flyback still turns on at a non-zero voltage. One proclaimed advantage of two-switch flyback, compared to traditional one-switch flyback, is that you don't need a lossy snubber as you can clamp the switching node voltage directly to the high voltage rail. But, you still get plenty of leakage inductance ringing, etc. So, it's not really a win for EMI...maybe even worse without any sort of snubber?Sorry wish I had a better answer!
Active Discharge circuit for large electrical motor - Page 1
Forum section: electronics / projects

author: eerocketman
author_rank: Contributor
timestamp: July 08, 2017, 10:52:27 pm
content: Hello,I am currently working on an active discharge safety circuit for a very large electrical motor to trigger at the event of an emergency stop.Can anyone advise me as to whether an IGBT or relay is the best option for the main discharge switch. I am dealing with around 100 Amps at a max voltage of up to 500V.

author: Circlotron
author_rank: Super Contributor
timestamp: July 08, 2017, 11:28:42 pm
content: What exactly do you want to discharge? A motor itself has nothing to discharge. Is it a large DC link capacitor in a variable speed drive?

author: jordanp123
author_rank: Regular Contributor
timestamp: July 09, 2017, 12:03:33 am
content: If your working with a large motor, then you may have access to antiquated or obsolete motor starter contactors, if so I would just use one of them, they are very robust, without looking anything up your looking at a NEMA 2 or so.

author: endevor100
author_rank: Contributor
timestamp: July 09, 2017, 04:26:33 am
content: If you're using a VFD or similar drive most of them have build in circuitry to do this. Brake resistor and regenerative resistor are terms I've seen on wiring diagrams. My understanding is that this is usually done with the IGBT both because of speed and cost.You are taking about a load of 50kW. For your own safety you should consider that if you have to ask this question you might not be able to foresee all of the potential dangers to yourself and your equipment from your design. You have a lot of potential to do hard with this much power, be smart.
active HDL in lattice diamond license problem - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: October 18, 2015, 11:12:48 am
content: Hi guys,I recently brought a lattice machx03LF dev board and I installed lattice diamond. I am using windows XP SP3 32 bit . when I started the lattice diamond after got the license from lattice it worked fine but when I start simulate my design active HDL is not shown up instead a error message shown up that "FlexLm error=-5 no such feature exists. I don't know what is wrong. I searched lattice site and It shown that active HDL license is included in lattice diamond package. somebody please help me guys.I also attached the screen shot of the screen of the error message. please guys.

author: marshallh
author_rank: Unknown
timestamp: October 18, 2015, 03:45:05 pm
content: Is Diamond even still supported on XP? Sounds like a paths problem.

author: marcopolo
author_rank: Regular Contributor
timestamp: April 17, 2016, 03:06:10 pm
content: Some problem for me with Win7 64-bitelectros6, have you found a solution?

author: marcopolo
author_rank: Regular Contributor
timestamp: April 17, 2016, 03:20:21 pm
content: Problem solved with a correct LM_LICENSE_FILE environment variable.

author: ale500
author_rank: Frequent Contributor
timestamp: July 04, 2016, 10:55:24 am
content: It seems that they got a themselves a licensing problem:I don't use Active-HDL often, but today I wanted to use it, and my license was expired. Generating a new one... did not solve my problem, yetCode:FEATURE LSC_BASE lattice 8.0 04-jul-2017 uncounted ............ \VENDOR_STRING="ispLEVER BASE" HOSTID=............FEATURE LSC_SYNPLIFY lattice 8.0 04-jul-2017 0 0 "ispLEVER System with Synplicity" ............FEATURE LSC_SYNPLIFYPRO1 lattice 10.0 04-jul-2017 uncounted \85D9393AFA9C VENDOR_STRING="ispLEVER System with Synplicity \Pro 1" HOSTID=............FEATURE LSC_ADVANCED_DSP lattice 10.0 04-jul-2017 uncounted \EAECFDC810A4 VENDOR_STRING="ispLEVER DSP" HOSTID=............FEATURE LSC_DIAMOND_A lattice 10.0 04-jul-2017 uncounted ............ \VENDOR_STRING="Diamond Free" HOSTID=............Feature has expired.Feature: ACTIVEHDL_LATTICE_LIC_GENExpire date: 30-jun-2016License path: /webprod/source/site-bin/aldec_license.dat:FLEXnet Licensing error:-10,32For further information, refer to the FLEXnet Licensing documentation,available at "www.macrovision.com".
Active Integrator Circuit - Page 1
Forum section: electronics / projects

author: aldanisvigo
author_rank: Newbie
timestamp: March 05, 2019, 06:51:07 pm
content: So I have a question. When creating op-amp integrator circuits, how do you choose the components attached to the op-amp so that you end up with the correct desired triangle wave?For example, say I put a 1KHz square wave into the inverting input, how do I choose the capacitor and resistors so that I will get a 1KHz Triangle Wave on the output? Example circuit below.R2|------/\/\/\------|| |---------||--------|| C1 || _ |R1 | | \ |-------\/\/\/\--------| - \ || | \_____|___ /\/\/\/\/\/\/\/\ (1VPk-Pk 1KHz) Triangle wave| --------| + /(1VPk-Pk 1KHz ) | | /_|‾|_|‾|_|‾|_ | |_ /_|__GNDSo really what I am after is any tricks or tips on how do I figure out R1, C1 and R2 so that the conditions are satisfied and I get a 1KHz 1VPk-Pk wave on the output pin of the op-amp? Any help you guys can provide me will be greatly appreciated. Thanks.

author: magic
author_rank: Super Contributor
timestamp: March 05, 2019, 10:12:49 pm
content: Frequency is of course the same in and out.Pick some sensible R1, like 1k. The current through C1 is C1·dV/dt, where dV/dt is the output rise/fall rate in V/s, and it is essentially equal to the current through R1, which you calculate easily. Pick C1 such that you get the dV/dt it takes to reach the desired amplitude in each half of the signal period.Pick R2 such that R2·C1 is greater than 10x the period in seconds, i.e. 10·0.001 for 1kHz. Increase for less distortion, reduce for better output centering around zero. If unpractically large, try again with lower R1.

author: aldanisvigo
author_rank: Newbie
timestamp: March 05, 2019, 11:41:37 pm
content: Hey thanks so much for your reply. I will give this a go and post what I come up with. Thanks you so much.
Active Load - Page 1
Forum section: electronics / projects

author: janengelbrecht
author_rank: Regular Contributor
timestamp: November 13, 2014, 07:00:05 am
content: Inspired by Daves Active Load design:Suggestions and comments will be appreciatedIts seems to work...but i need another FET and rail-to-rail OpAmp.The expensive 10 turns pots is not ideal too.My problem really is that i think the opamp that drive the MOSFET ought to have an output voltage at 4.5V...but it is nearly 1 Volt higher....hmm..... maybe I ought to go back to my uni and start all overNot that it in any way influences the function of the circuitIts just....it shouldnt really work as i see it....but it does(The OpAmp U1:A has a resistor with a really high value : Gate-source resistance in MOSFET as its feedback resistance so it ought to have an amplification near its Open Loop Av. So one would assume it acts like a comparator ? Then it should settle at half supply when there is 0 volt difference between its inputs. Well if such things as offset errors didnt exist - Tried to remove R2 - no difference!What is it i am missing ? God damn...now i can feel i only has worked with software the last 19 years)

author: Richard Head
author_rank: Frequent Contributor
timestamp: November 13, 2014, 07:54:51 am
content: Why two pots and not just a resistor in series to limit the range?I would add a bit of hysteresis on the current limit so the current limit LED either goes ON or OFF and not gradually switches on.I suggest some bypass caps across the power rails and Zener also.

author: janengelbrecht
author_rank: Regular Contributor
timestamp: November 13, 2014, 07:57:39 am
content: Hmm two pots for coarse and fine adjustYour other advice i will implement at once - thx....still i have some troubles understanding why it actually worksIn my next project i will not use this trial/error approach in my design proces but actually calculate it all firstCurrent limiting LED: It really doesnt gradually turn on/off.....Its either ON or OFF

author: Seekonk
author_rank: Super Contributor
timestamp: November 13, 2014, 08:48:52 am
content: I would expect to find the fine pot to be in series with the course pot source voltage source OR something like a 20K resistor in the lower leg of the fine pot. As it is the course pot sets the max voltage and the fine pot is 0-100% of that.
Active loop filter for a PLL, opamp caveats? - Page 1
Forum section: electronics / projects

author: mathias
author_rank: Regular Contributor
timestamp: June 20, 2014, 06:50:07 pm
content: Hi all,I was playing around with an active filter for a PLL I built. The filter was designed with ADISimPLL and built with an ADF4002 PLL chip and SP869 VCO. I never gave much attention to the opamp in the circuit and started out with a OPA227 (low noise, GBW of 8MHz). The loop filter had a designed bandwidth of 10kHz. When I built it up, the output was extremely dirty, not really locking at all. The Vtune signal was a nice triangle though. Then I switched to the LT1115 (GBW of 70MHz) and it would lock, but still a very dirty spectrum on the SA. Adding some caps between output and input of the opamp ameliorated the situation.Now comes my questions: what are the typical caveats with designing active PLL loop filter that aren't mentioned in the app notes?

author: KJDS
author_rank: Super Contributor
timestamp: June 20, 2014, 08:02:03 pm
content: Make sure that the op-amp is decoupled properly. PSRR may well be very high at low frequencies, but will fall as frequency rises. It's worth having a separate regulator for the logic and the op-amp.Make sure that the inputs and output aren't at the supply rails or you'll run into more problems.

author: w2aew
author_rank: Super Contributor
timestamp: June 20, 2014, 08:38:37 pm
content: Don't forget that the loop already has one pole in it. The loop filter controls the *frequency* of the VCO, but the phase detector that drives the loop filter measures *phase*. Thus, even if you use a first order filter, the overall loop response is 2nd order. Thus, watch out for underdamped response, etc.

author: moffy
author_rank: Super Contributor
timestamp: June 21, 2014, 12:08:36 am
content: What I think is happening is that the input products(multiple of input waveform and VCO) have some large high frequency components, so that even though your loop bandwidth is only 10kHz the lower GBW product opamp can't cope. The inverting pin is not being held close to the non inverting pin. You can try and prefilter these components as long as the prefilter is well outside the capture loop frequency.

author: mathias
author_rank: Regular Contributor
timestamp: June 21, 2014, 06:30:47 am
content: @w2aew: I would think/hope that the ADISimPLL software would already take this into account. I'm not well educated enough (in the field of EE) to design a filter from scratch, so I have to rely on other peoples calculations. A video by Dave on this subject is highly welcome.@moffy: I'll play around with the PFD frequency. Currently it was set at 1MHz.

author: moffy
author_rank: Super Contributor
timestamp: June 22, 2014, 05:20:36 am
content: Yeah I have seen the same thing before while designing my own sigma/delta converter. If the products have high frequency components the GBW product of the filter has to be very high.
Active-Low enable input driven by high voltage signal - Page 1
Forum section: electronics / projects

author: mspider65
author_rank: Contributor
timestamp: September 20, 2021, 09:12:11 am
content: Due to the chip shortage I am trying to adapt a circuit to use what is available.In particular, I have to replace a Step-Down which, starting from the voltage of an e-bike battery, should generate 5V.The doubt concerns the Enable signal of the new DC-DC which is now active low.What I have is an output (PSU_ON) which in case of ON is at battery voltage while in case of OFF it is at GND or floating.The EN input must be less than 0,8V to enable the chip and must be above 1,8V to disable the chip.Max Voltage at enable pin is 7V.I thought of using the circuit you see below but I ask those who have more experience than me for an opinion if it can be good or if there is a better way to go.In particular i have a very small footprint to accommodate everything and any suggestion to lower the number of nedded component is welcome.

author: gcewing
author_rank: Regular Contributor
timestamp: September 20, 2021, 11:50:04 am
content: At VIN = 60V, the high level at EN will be about 6.9V, which is getting rather close to the absolute maximum of 7V. You might want to decrease R4 a little, although that would reduce your high level margin at lower VIN.It might be better to replace R4 with a zener to clamp the high level to 4 or 5 volts.

author: mspider65
author_rank: Contributor
timestamp: September 20, 2021, 12:18:54 pm
content: You are right, a Zener is much better to clamp the EN voltage regardless of the VIN value.As for R1, how far can its value be safety increased to reduce the current when the circuit is off?

author: iMo
author_rank: Super Contributor
timestamp: September 20, 2021, 06:15:09 pm
content: So we waste our time?https://www.eevblog.com/forum/beginners/active-low-enable-input-driven-by-high-voltage-signal/msg3699757/#msg3699757
Active PFC Waveforms - Page 1
Forum section: electronics / projects

author: Digibin
author_rank: Regular Contributor
timestamp: May 02, 2016, 07:15:04 pm
content: I'm looking at using theLT1249for active power factor correction in a ~400W SMPS design. I've taken the example LTSpice schematic available from the website and altered it for my application (output voltage, line current limit, Zener power supply network). Based on simulations the circuit is achieving a power factor of around 0.89 at full load, dropping to ~0.7 at very light load. My question is what PF would be considered reasonable for a 400W application? I appreciate 'reasonable' is ambiguous. I just mean a typical ball park figure, as I really have no idea. I don't know what the relevant standards require (IEC61000-3-2?), but I'm not designing to meet any standards, I just want to be in the right ball park.Schematic attached for info. So what should I be aiming for, roughly speaking, for a 400W SMPS application? And if I need to, how might I improve the PF... increase L? Different controller topology/mode?

author: Digibin
author_rank: Regular Contributor
timestamp: May 03, 2016, 07:44:01 pm
content: Anyone?

author: Marco
author_rank: Super Contributor
timestamp: May 03, 2016, 08:21:45 pm
content: All I know is that that is below the minimum requirements for PC PSU 80 PLUS certification (.90 at full load, 80 PLUS Titanium even requires .95 from 20% load and up).

author: Wolfram
author_rank: Frequent Contributor
timestamp: May 04, 2016, 02:45:24 pm
content: A few things are not right with the circuit, particularly the low voltage supply part. On every switching cycle, the MOSFET has to absorb most of the energy stored in C7, resulting in 100+ ampere current spikes through the MOSFET and significant power loss. I would suggest starting from the LT1249 example circuit supplied with LTSpice, and playing with the component values one by one to get a feeling of how it works.
Active SLA Battery Desulfator / Charger with MCU Battery Status Monitoring - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 03, 2018, 01:29:51 pm
content: this is my 40V 5A Lead Acid battery Desulfator / Charger with 1.25 - 30V SMPS PSU. Features are:1) MCU (atTiny13A) controlled pulse between 500 - 2500 Hz user adjustable2) adjustable pulse duty cycle 1 - 80%3) can desulfate/charge 6, 12, 24V lead acid batteries4) Pulse/desulfate/charge every 10 seconds, rest 1 second and check battery status. If battery is full ( equal or more than 6.75, 13.5, 27V), stop pulse and beep twice every 5 seconds.5) If battery not connected, stop desulfation/charge process.6) If user set duty cycle to less than 30%, the unit will go into unconditional trickle charge (no battery voltage level monitor)7) Internal Mosfet (power element) Damage or input overvoltage check by continuous warning beep.8} 2 SMPS output since i have more room on the PCBsome idea and inspiration came from this thread...https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/msg1253994/#msg1253994with mcu control, error can also be checked (and beep accordingly):Attached are the schematics and the build process. As of this post, this unit has been working 24/7 for the past 4 weeks repairing my old batteries.. FWIW...Best regards...
Active Twin-T Notch and Sallen-Key LPF with Summing - Page 1
Forum section: electronics / projects

author: fyberlabs
author_rank: Newbie
timestamp: January 05, 2015, 10:31:39 am
content: Hi, I am working on an analog notch filter in SMD to a low Q Sallen-Key LPF that does Summing to shift the signal up from -3.3-3.3v to 0-3.3v. This is for a high impedance ECG sensor from Plessey.I just wanted some sanity checking and advice. It is hard to get 1% capacitors and resistors, but I think I can get a 'good enough' design with 5% as necessary. As is I centered it around 55Hz as tolerance and drop at 50Hz and 60Hz is pretty significant. I have set the LPF at 1KHz and made it a 3rd order, though I might set it lower. I believe I am getting decent results with feedback from both sets of filters, so that worries me.Anyway, attached is a picture of the design. The spice files are athttps://github.com/FyberLabs/FlexModule/tree/master/sensors/ECGADCBuffer/notched/sims. I welcome any advice on the design.Thanks!

author: fyberlabs
author_rank: Newbie
timestamp: January 06, 2015, 06:44:54 am
content: Updated values after running more sims and tweaking values to more available components. All caps will have to be 10% and ceramic and resistors will be 5%, but 1% is order-able from factory. Repo updated and here is the new layout for the sim.
Acute and right angle for PCB traces? - Page 1
Forum section: electronics / projects

author: slcf2003
author_rank: Newbie
timestamp: November 17, 2022, 04:54:44 pm
content: I'm still new on PCB layout. It is the first time I have to connect a 5V power trace to 2 different ICs in a triangle arrangement, and I'm not really sure how I should do it. I did some researches online and also in the forum, and I saw people agree and disagree with using acute and right angle on traces.This is how it is like in my layout:There's acute angle in this solution:There's right angle in this one:I only came up with these 2 solutions. Could someone tell me which one is better, or maybe there's another way to connect these 3 points together for a low-frequency signal or power traces in my case?Thank you.

author: tszaboo
author_rank: Super Contributor
timestamp: November 17, 2022, 05:19:06 pm
content: This is not an issue anymore with modern PCB manufacturing. Even before, you just got a slightly larger number of failed board, but I don't think anyone has good statistics on how much of an issue this was. Might be the difference between 0.1% and 0.3% of boards failing. Route the way you like it.

author: janoc
author_rank: Super Contributor
timestamp: November 17, 2022, 05:21:12 pm
content: If nothing else, the T-shaped junctions look better than the "spiky" acute angle traces.

author: Vovk_Z
author_rank: Super Contributor
timestamp: November 20, 2022, 09:43:39 am
content: I don't see T-shape as more beautiful and triangle will definitely work better, because it lowers an interraction between different ICs.Triangle is better both for precision DC circuits and of cause for high-speed circuits.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 21, 2022, 10:16:19 pm
content: Obviously this is more aesthetically pleasing

author: Vovk_Z
author_rank: Super Contributor
timestamp: November 22, 2022, 08:06:14 am
content: It depends on if it is a small-signal route or it is a power line.
Ad hoc ZIF Kelvin probe for axial THT components - Page 1
Forum section: electronics / projects

author: RoGeorge
author_rank: Super Contributor
timestamp: December 15, 2023, 10:21:45 pm
content: Four square golden pins, twisted 45 degree, soldered on a perfboard, then bent as in the picture, but without touching each other, and with a plastic band to press the DUT against them. Note that the golden pins are pressing against the DUT terminals with one of their edges, and not with their flat side.The plastic band is a piece of ice cream bucket handle, anchored on the perfboard with two paper staples.Solder each wire from the Kelvin probe to a pin, and the springiness will do the rest.

author: mawyatt
author_rank: Super Contributor
timestamp: December 16, 2023, 01:54:18 pm
content: Clever idea!!Best,
AD quiz thevenin vs norton - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: March 12, 2025, 09:50:29 pm
content: https://ez.analog.com/how-to-use-engineerzone/logic-lounge/f/quizzes/579578/kcc-s-quizzes-aqq254-about-thevenin-norton-dipoles-enigmaWhat I thought is that for a truely ideal stable voltage the loss would need to be 0 so it would be like a super insulator (sphere in sphere charged capacitor floating in deep space locked in a orbit so there is no support structure to leak charge), and for a no power loss current it would need to be a super conductor loopand one makes a magnetic field but the other one has some fringe electric field from the interconnects
AD202KN...worth salvaging? - Page 1
Forum section: electronics / projects

author: KTP
author_rank: Frequent Contributor
timestamp: August 01, 2012, 05:53:37 pm
content: While cleaning out my machine shop area, I stumbled across a older board (date code 1997) from a 30J ruby laser. It has quite a few AD202KN parts, which seem to be a somewhat slow isolation amplifier. Should I bother desoldering these modules, or just bin it? I can't think of an immediate use for them, and I am trying to reduce garbage..

author: SeanB
author_rank: Super Contributor
timestamp: August 01, 2012, 06:51:34 pm
content: Whip them off, if nothing else you can use them as an isolated power supply for low current loads.

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 01, 2012, 06:58:38 pm
content: This must be the first datasheet I've ever seen that starts the features list with channels per inch

author: Short Circuit
author_rank: Frequent Contributor
timestamp: August 01, 2012, 08:28:42 pm
content: Seems a fairly universal device, and quite expensive.Might be worthwhile to dump the board on eBay (or the EEV for sale section).
AD4110 eval, etc - Page 1
Forum section: electronics / projects

author: cncjerry
author_rank: Unknown
timestamp: January 29, 2020, 11:39:29 am
content: Anyone using one of these in either a chip-based, custom PCB, or eval solution? The eval is a 24bit, up to +/-10v, ADC that comes with software. Its $99 but it looks like you need a general purpose ADI SDP-B as well for $50.Thanks
AD5206 zipper noise reduction, zero crossing questions.  - Page 1
Forum section: electronics / projects

author: iampoor
author_rank: Frequent Contributor
timestamp: May 31, 2016, 02:58:32 am
content: Zipper Noise reductionHiIn my current project, I am planning on using an AD5206 digital pot. I am planning on using all 6 channels for (effectively) volume controls. Eliminating zipper noise is my #1 priority. Analog Devices suggests using the zero crossing detector in the AD5290 datasheet, but it is designed for only 1 channel. If I wanted to use this for 6 channels, would I simply build a zero crossing detector for each channel and then cascade the outputs of the AND gates together? I am not sure if there is a more elegant solution, but if it works...it works I suppose. My concern is that in some situations, not all the channels would simultaneously be at a zero crossing state and that the pot may not automatically update (As the chipselect line would not go high). Is there a more elegant solution?
AD5290 Digital Potentiometer with dual supply - Page 1
Forum section: electronics / projects

author: drewman2000
author_rank: Newbie
timestamp: December 05, 2013, 09:03:28 pm
content: The issue I'm having is that have a AD5290 that needs to be able to have voltages on the A/W/B terminals that go between +-12V. Therefore I currently have Vss connected to the negative 12V rail of my power supply and Vdd is connected to the positive 12V rail. I'm using an Arduino Mega 2560 to send SPI commands and if I want to power the Arduino via the positive 12V rail I can't ground it without causing issues. If I ground it to the common ground of my power supply then whenever I connect the Arduino ground to the digital ground on the AD5290 I short the negative rail of my power supply, any suggestions on a work around?

author: Skimask
author_rank: Super Contributor
timestamp: December 05, 2013, 10:04:24 pm
content: Shouldn't have any problems. I've been using the AD5290 for the past year or so and hooked up to a MegaADK.AD5290 pin 3 to -12AD5290 pin 4 to digital ground (e.g. 0 volts)AD5290 pin 9 to +12MegaADK gets power off the +12v rail thru a regulator.Works fine.Let's see your power supply.

author: drewman2000
author_rank: Newbie
timestamp: December 06, 2013, 04:41:08 pm
content: Figured it out, bad chip lol. I guess I must have wired it up wrong one of these times and it didn't like it, thanks for the quick response!

author: Skimask
author_rank: Super Contributor
timestamp: December 06, 2013, 07:07:51 pm
content: I've got 4 AD290's mounted on SMT-DIP adapter boards that I play with from time to time...or rather HAD 4 of them.Haven't miswired any of them, but still somehow managed to blow the pot out of 3 of them.Touchy things...
AD5290 Help - Page 1
Forum section: electronics / projects

author: DevTeck
author_rank: Newbie
timestamp: February 02, 2016, 08:03:45 pm
content: Hello all,I need some help in connecting the AD5290(Data Sheethttp://www.analog.com/media/en/technical-documentation/data-sheets/AD5290.pdf) Digital potentiometer to a KBRG-225D(data Sheethttp://www.kbelectronics.com/manuals/kbrg_255_manual.pdfmotor controller). I am trying to replace the circuitry that in figure 6 on page 9 of the KBRG that utilizes the Bidirectional with reversing contact. Pin 10 is a +10Vdc and pin 11 is a -10Vdc and which is then wired in to a the potentiometer to pins 12 and 13 where pin 13 is a "Common" pin. So my question is Can someone suggest how to wire this in to adjust the +/- voltage from pins 10 and 11 into pins 12 and 13. Thanks for any help and have a great day.

author: Paul Price
author_rank: Super Contributor
timestamp: February 04, 2016, 01:03:53 am
content: Speed Control Mode – When jumper J7 is set to the “SPD” position, the KBRG-255 willvary the motor speed as a function of the voltage on input terminals "12" (signal) and "13"(common). IMPORTANT: When J7 is set for speed control (“SPD”), J8 must be set to“S/LT” position (factory setting). The input voltage can be derived from the wiper of themain speed potentiometer or from an isolated analog input (voltage following mode). Sincethe KBRG-255 is a 4-quadrant regenerative drive, the motor speed will follow both apositive and negative wiper voltage and drive the motor in both the forward direction andreverse direction. In addition, it will apply both forward and reverse torque in order tostabilize motor speed.Since you must use a MCU to control the AD part, then you have available A2D inputs that can measure measure voltages from the controller and be used to set the solid-state pot to control speed and direction. You write code to accomplish this.Be most aware that the adj. points are not AC mains isolated and you cannot get more than 5mA max. out of the digital pot, some buffering would be required.

author: DevTeck
author_rank: Newbie
timestamp: February 07, 2016, 05:43:01 pm
content: Quote from: Paul Price on February 04, 2016, 01:03:53 am
AD5331 10 bit D/A  - Page 1
Forum section: electronics / projects

author: JohnnyP
author_rank: Regular Contributor
timestamp: February 02, 2015, 11:26:39 pm
content: The AD5331 us a parallel D/A. Has anyone used it?Can I use it with an 8 bit uP without using a storage register for the lower 8 bits?The data sheet says the input register is double buffered, but it's a little hard for me to understand.Thanks for any help.Link to data sheet:http://www.analog.com/static/imported-files/data_sheets/AD5330_5331_5340_5341.pdf