hybridfree/eevblog-posts huggingface dataset:
SPI Test Device - Page 1
Forum section: electronics / beginners

author: aep9690
author_rank: Regular Contributor
timestamp: May 12, 2013, 02:07:43 am
content: The answer to this maybe on the internet somewhere, however the terminology I am using is kind of vague so it might not be showing up in my search results. But anyway here it goes.I am trying to build a battery management system for an electric vehicle, the battery management chip communicates via a 4 wire SPI bus. I am using the MSP430G2253 to communicate with the chips and perform the cell balancing. I am writing the code to send and receive data from the microcontroller, I would like to have some sort of dummy device that can receive data and then send something back, so I can make sure that the code I wrote is correct.Does something like this exist, or does anyone have any ideas of what I could use?

author: Skimask
author_rank: Super Contributor
timestamp: May 12, 2013, 02:18:11 am
content: Disclaimer: I'm not MSP430 savvy...Does the MSP430's SPI "read in" the SPI data at the same time it "writes out" the SPI data? (The PIC's do it that way, but again, I don't do MSP430's)Couldn't you just do a loop back?Or if you're looking to fire out a 'command' and get back a 'response' (whether it's simulated or otherwise), set up another MSP430 as a slave SPI device and have it send back your dummy data.

author: c4757p
author_rank: Super Contributor
timestamp: May 12, 2013, 02:21:14 am
content: Quote from: Skimask on May 12, 2013, 02:18:11 amIsn't this how bidirectional SPI is always supposed to work?

author: aep9690
author_rank: Regular Contributor
timestamp: May 12, 2013, 02:28:58 am
content: I'm not very familiar with microcontrollers in the first place, but I believe the way it works is that once the GPIO pins are configured as MOSI ans MISO they have 8 bit buffers that you can write to to send data and read from the receive it.The loop back idea is brilliant, I haven't thought of that. I think I will try that and see if it works. Thanks.

author: Skimask
author_rank: Super Contributor
timestamp: May 12, 2013, 02:51:14 am
content: Quote from: c4757p on May 12, 2013, 02:21:14 amBidirectional, sure...But simultaneously bidirectional, where you shift stuff in at exactly the same time as you shift stuff out, I've never had a need to use the SPI module in that way.

author: nuhamind2
author_rank: Regular Contributor
timestamp: May 12, 2013, 03:26:52 am
content: Try buspirate

author: aep9690
author_rank: Regular Contributor
timestamp: May 12, 2013, 06:08:05 am
content: I looked up buspirate, it seems like it could do the job. But it seems like it is meant to act as a master.

author: amyk
author_rank: Super Contributor
timestamp: May 12, 2013, 09:47:58 am
content: What do you need to test exactly? An SPI flash might be of some use.

author: kripton2035
author_rank: Super Contributor
timestamp: May 12, 2013, 10:14:09 am
content: buy any spi peripheral simple to use like a real time clock, a peripheral extension, or a temperature sensorthen you will have a simple spi device to talk to and try your code with that.
SPICE - Measuring impedance and phase - Page 1
Forum section: electronics / beginners

author: Chryseus
author_rank: Regular Contributor
timestamp: July 01, 2011, 09:28:28 pm
content: Hey guys, I've started playing around with ngspice and LTspice and have been wondering how to doinput / output impedance measurement along with phase shift.I've made a quick series RCL circuit that I've already worked out on paper, for a signal of 1MHz theimpedance should be 1004.63 ohms with a phase angle of -5.5 degrees.Code:RCL Impedance TestV1 1 0 AC 1 DC 1Vamm 1 2 AC 0 DC 0R1 2 3 1kC1 3 4 1nFL1 4 0 10uH.ac lin 2 1meg 1meg.endI have already worked out how to measure the input impedance with Z = V(1)/I(Vamm) whichworks fine in LTspice but I get a rather odd result of 1009.279 ohms in ngspice.I'm also not quite sure how to measure the phase or output impedance, Vamm in LTspice shows5.5 degrees imaginary but I don't think that is right seeing as it is positive rather than negative.Help would be very much appreciated.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 01, 2011, 10:36:05 pm
content: See V(out) in attachment.

author: Chryseus
author_rank: Regular Contributor
timestamp: July 01, 2011, 10:51:00 pm
content: Quote from: BoredAtWork on July 01, 2011, 10:36:05 pmThanks mate that is very helpful, now all I need to do is figure out how to measure phase properlyand stop ngspice giving odd results.editNever mind I got it all working now, I used the example you gave me and moved the constant current source to the inputwhich easily gives the input impedance and phase, ngspice is still giving garbage data though.
Spice model file for SMS7630 schottky Diode - Page 1
Forum section: electronics / beginners

author: haniy
author_rank: Newbie
timestamp: February 19, 2025, 01:39:40 pm
content: hello,I was wondering if anyone would know or have the spice model for this particular diode...I have looked through its data sheet but all that I could find is its SPICE model parameter but not the file itself.I have also never used CST so i'm not sure if the parameter is sufficient to do the simulation with the diode (i'm working on Rectenna and using this diode as the rectifier circuit)
SPICE model for LT1082 - Page 1
Forum section: electronics / beginners

author: elki
author_rank: Regular Contributor
timestamp: September 04, 2023, 09:14:47 am
content: Does anyone have a SPICE model to use in KiCad for LT1082 voltage regulator?Thanks!

author: Andree Henkel
author_rank: Regular Contributor
timestamp: September 04, 2023, 10:50:38 am
content: In LTSpice there is a model for it.Maybe simulate your Circuit with LTSpice?

author: elki
author_rank: Regular Contributor
timestamp: September 04, 2023, 10:53:48 am
content: Yes, I can of course do it in LTspice; was just wondering if there is any similar SPICE model that I can use in KiCad - I see there are other similar boost converters like LM2577, but also no decrypted models around.

author: liaifat85
author_rank: Regular Contributor
timestamp: September 04, 2023, 03:07:51 pm
content: Maybe you can ask this to the KICAD forum too.

author: elki
author_rank: Regular Contributor
timestamp: September 04, 2023, 03:10:18 pm
content: Yep, already didQuote from: liaifat85 on September 04, 2023, 03:07:51 pm
SPICE Model for NE602 Wanted - Page 1
Forum section: electronics / beginners

author: Alexandros81
author_rank: Regular Contributor
timestamp: July 17, 2018, 08:36:07 pm
content: Hi!I am trying to find spice model for the NE602 mixer or the SA602 or the SA612I have done a search on the web with no success finding any models.I want them for TINA.Do they exist?

author: Benta
author_rank: Super Contributor
timestamp: July 17, 2018, 10:09:35 pm
content: I'd ask NXP. If they don't have it, odds are it doesn't exist. You normally don't use Spice for VHF-frequency simulation.

author: iMo
author_rank: Super Contributor
timestamp: July 18, 2018, 05:31:57 pm
content: http://ltwiki.org/files/LTspiceIV/examples/LtSpicePlus/Rf/SA612%20LTSpice%20Model%20Rev%2004/https://github.com/dprentiss/KC3FOH/tree/master/spice/SA612NE602 is not produced anymore (discontinued ~20y back), the NE612 is the replacement.. Search for "NE612" or "SA612" instead..
Spice Model - Page 1
Forum section: electronics / beginners

author: nasrmiad
author_rank: Contributor
timestamp: February 14, 2012, 01:22:53 am
content: Where can I find Spice models for devices that don't have a simulation model in altium designer? devices such as the L293D? Thanks.

author: Rerouter
author_rank: Super Contributor
timestamp: February 14, 2012, 02:38:18 am
content: the manufacturer of the parts website?

author: nasrmiad
author_rank: Contributor
timestamp: February 14, 2012, 02:57:06 pm
content: Quote from: Rerouter on February 14, 2012, 02:38:18 amFor example st micro, doesnt have the L293D model on their website.

author: Bored@Work
author_rank: Super Contributor
timestamp: February 14, 2012, 03:17:33 pm
content: Quote from: nasrmiad on February 14, 2012, 02:57:06 pmThen build your own model, pay someone to build a model for you, substitute the part with (an approximation of an) equivalent circuit, don't simulate the part of the circuit that uses the particular part, or don't simulate at all.
SPICE Models Database - Page 1
Forum section: electronics / beginners

author: masster
author_rank: Regular Contributor
timestamp: May 22, 2015, 10:34:33 pm
content: Hello everybody!I would like to know if there is a comprehensive SPICE Models Database online?I am working with NI Circuit Design Suite (Multisim) and I can't find 2 parts:- voltage regulator LM2940T-8.0- a generic analogue gauge for showing the fuel quantity in a car (those with 2 coils)Thank you.
Spice Models for Eagle or how do I do it... - Page 1
Forum section: electronics / beginners

author: JeRo
author_rank: Newbie
timestamp: March 02, 2021, 05:59:49 pm
content: Hi from Germany guys!I am trying to simulate with Eagle and I can not figure how I get a simple voltage regulator to be simulated. I am new to simulation so any help is appreciated...Cheers,jens

author: jpanhalt
author_rank: Super Contributor
timestamp: March 02, 2021, 06:12:00 pm
content: It might help to know which version of Eagle you are using. Toward the end of its run as an independent entity (versions before, Eagle tried to incorporate LTSpice. The models were very limited, and I found it useless. Autodesk has abandoned that approach and has its own simulation program, as I understand it.I use Eagle 7.7.0 or 7.2. I do not use an Autodesk version and am not familiar with its offerings.

author: JeRo
author_rank: Newbie
timestamp: March 02, 2021, 07:57:08 pm
content: Hi, thanks for your answer, I am using Version 9.6.2.
spice question - Page 1
Forum section: electronics / beginners

author: KTP
author_rank: Frequent Contributor
timestamp: October 07, 2010, 02:41:16 pm
content: Does anyone know what hold time or delay time is used in a nested dc sweep in LTspice?Is there a way to change this value?example:.dc V1 0 10 .01 V2 1 3 .5(this will sweep voltage source V1 in a ramp from 0 to 10 volts five times for values of V2 of 1,1.5,2,2.5 and 3 volts)how long does LTspice dwell on each measurement point in the simulation?

author: Bored@Work
author_rank: Super Contributor
timestamp: October 07, 2010, 04:37:39 pm
content: There shouldn't be any hold or delay time. SPICE picks a pair of values and performs a DC operating point analysis for that pair of voltages. When it has found a result it moves to the next pair and again does an operating point analysis. Until all pair combinations have been run.

author: KTP
author_rank: Frequent Contributor
timestamp: October 07, 2010, 04:58:50 pm
content: I guess I don't understand. In this application I was simulating a curve tracer for a 2n3904. (To approach a real world simulation we have to do in our lab next week I chose to use a base and collector resistor instead of applying the voltage sources directly to the terminals). It works fine and all, but how does LTspice know to sweep at a slow enough rate, or what timing does it use for the ramp in the inner loop such that it can perform the dc operating point analysis. Does my question make any sense?Here is a screenshot of the simulation results. Note the 5 green curves are the collector current plotted against Vce for Vbe ranging from 1V to 3V. Also note the fat blue line is a plot of Ic/Ib (beta) vs Vce on the same graph.

author: allanw
author_rank: Frequent Contributor
timestamp: October 09, 2010, 02:21:00 am
content: DC operating point analysis means that it's not time-based at all. It opens capacitors and shorts inductors and finds the dc voltages.
SPICE/Keysight ADS Netlist Help - Page 1
Forum section: electronics / beginners

author: fourierpwn
author_rank: Regular Contributor
timestamp: August 06, 2016, 12:55:30 am
content: Hi guys, I am trying to import a nonlinear model for a HEMT device into Keysight ADS (beginner with ADS) and I don't understand the netlist format that ADS gives. I have been through Keysight tutorials to which they provide sample netlist files of a diode to import, which I understand. The nets in that are logical and I can see where everything should connect together. However, the HEMT model netlist format seems bizarre.Here is a screen capture of the model imported into ADS.I am aware that you can simply import the model as a netlist and use that in your design, or create a subcircuit to use, however I would like to know how all of the parasitics are connected so that I can reproduce the model myself (for use in other EDA packages).

author: fourierpwn
author_rank: Regular Contributor
timestamp: August 08, 2016, 03:20:19 am
content: Ignoring the netlist names and looking at the component names, I understand about Cgs, Cds, Cgd, Ls, Lg, Ld though I don't understand what the others are for, i.e., Cgs1, Cds1, Lg1 etc.Any ideas?
Spike in power line relay - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: September 10, 2024, 08:06:05 am
content: I have this circuit below.I have an issue where, when the input turns on the transistors, I see a spike in the nearby power supply rail. I have other power supply rails such as 3.3V and 5V. Whenever, the transistor turns ON, I see a spike of say 15V peak to peak on the 3.3V rail. This causes my ICs connected to 3.3V malfunction.However, the spike of 15V peak to peak is not happening always. The amplitude of the peak to peak spike varies by say +/-5VAttached in the circuit image.Can someone let me know why this happens and what fix I can try?

author: Phil1977
author_rank: Frequent Contributor
timestamp: September 10, 2024, 09:00:55 am
content: It´s strange that the spike happens when the relay is switched on. Usually the back-EMF when switching off relays is causing trouble, but here it must be something else.I´d do two things:- Put some decoupling capacitors on the power rails near the relay driver- Slow down the switching on of the transistor. E.g. by a 330pf-cap from base to emitter- Put a clamping zener or TVS on your 3.3V rail to protect the digital components.Are you sure that the spike is coming from the relay itself and not from it´s connected load? What kind of power supply do you have, is it possible it suffers from really bad cross-regulation?

author: ramussons
author_rank: Contributor
timestamp: September 10, 2024, 09:09:33 am
content: It is doubtful if the spike occurs from the shown schematic.Is the relay operating some other equipment?Where / How is the drive to the transistor generated? That also needs to be investigated.

author: tggzzz
author_rank: Super Contributor
timestamp: September 10, 2024, 09:37:06 am
content: Quote from: Freshman on September 10, 2024, 08:06:05 amThis could be a real effect, a consequence of how you are measuring the spike, or because of "stray/parasitic" components not included in your schematic.What is the relay switching, and is that load connected to the components shown in the schematic?Show photo of implementation, how you are measuring the spike, and the measurement.

author: BeBuLamar
author_rank: Super Contributor
timestamp: September 10, 2024, 06:04:58 pm
content: Usually there is a spike in of negative voltage when you switch off but the diode should clamp it.

author: Zero999
author_rank: Super Contributor
timestamp: September 11, 2024, 12:48:40 pm
content: Presumably the diodes are connected to the transistor's collector and the coil?Here's the correct way of drawing it.Note the bottom diode doesn't do anything. It never conducts.

author: djococaud
author_rank: Regular Contributor
timestamp: September 12, 2024, 05:37:20 am
content: The 1N400x is way too slow to absorb the spike from the relay coil. Try a schotty diode instead (like 10MQ100N or similar)
Spiky-shaped PCB pads? - Page 1
Forum section: electronics / beginners

author: lpc32
author_rank: Frequent Contributor
timestamp: May 19, 2015, 12:06:18 pm
content: What's the point of these pads?

author: Simon
author_rank: Unknown
timestamp: May 19, 2015, 12:08:58 pm
content: It looks to me like they have bent the pins of the connector over and made a pad to suit that.

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 19, 2015, 12:27:00 pm
content: Quote from: lpc32 on May 19, 2015, 12:06:18 pmCouldn't help but notice your pun. Not sure if it was intended.I think the spikes may have something to do with "solder thieves" for wave soldering.

author: lpc32
author_rank: Frequent Contributor
timestamp: May 19, 2015, 01:41:05 pm
content: Simon, it's difficult to see in the photos, but the pins aren't bent.I think it indeed may be solder thieves/robber pads:http://www.ami.ac.uk/courses/topics/0170_wsp/#4Though, why are some pins exempt in the second photo?Is this a common practice? I don't think I've these before.PS: Pun intended, but there's nothing more annoying than referencing it in line.

author: amyk
author_rank: Super Contributor
timestamp: May 19, 2015, 01:44:30 pm
content: If they were for wave soldering they'd be pointing in the same direction.My guess is ESD dissipation spark gaps.

author: lpc32
author_rank: Frequent Contributor
timestamp: May 19, 2015, 01:47:00 pm
content: Not constraints due to connector pin positions, and diagonally works too?

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 19, 2015, 01:47:55 pm
content: Well, they are roughly pointing to the left. Some are tilted away but still slightly towards the left....If they are PCB spark gaps, there should be another exposed area near it that is connected to ground. And you don't usually put spark gaps to ground pins
Spirit fitness XBU 55 repair - Page 1
Forum section: electronics / beginners

author: PeKi
author_rank: Newbie
timestamp: March 19, 2025, 04:46:00 pm
content: Hello!I had an error with a spirit fitness xbu 55 exercise bike. When I plug it in, all lights light up and the screen turns blue. After that, nothing happens.I have tested all sensors in the bike, and I think they are working (maybe they aren't, all resistances-voltages seemed to be OK to me).Is there a place I might find the main board's schematic, or would someone be willing to baby me through diagnosing it?TIA

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: March 21, 2025, 09:57:25 am
content: Here is the owner manual.https://www.spiritfitness.com/pub/media/wysiwyg/service/XBU55_OM_20181011.pdfIt may help you to troubleshoot the other parts.

author: PeKi
author_rank: Newbie
timestamp: March 24, 2025, 12:58:06 am
content: Thanks!Realised, that *something* in the console is broken, and drawings aren't available. Traced it to a broken LDO supplying the main chip. Currently waiting for replacement
Split rail function generator or single rail ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: March 28, 2018, 12:36:41 pm
content: I want to make a project to use a little split rail linear PSU I should have made already. So I'd like to make some BJT and/or op-amp function gen. like they might have in the 1960/70s with RC and LC circuits for audio frequency and AM band (if I can find a 'real' schematic') and solder it up today for fun.Do professional/$$$ function generators usually output +V/-V or is it 0-->V+ ? I have a XR2206 function gen. kit that's single rail, so I should built a split rail type I guess.
Split-rail or single supply for ADC/PGA with differential input. - Page 1
Forum section: electronics / beginners

author: bluespider
author_rank: Contributor
timestamp: September 19, 2024, 10:14:17 am
content: I am redesigning a circuit that has an ADC IC - The existing version uses a +/-2.5V supply for the ADC and its integrated PGA. The input is isolated differential, and the circuit is battery powered. The have always been more parts on the circuit board that required a negative voltage supply (+/-5V). Those parts are no longer needed so the only negative voltage required is for the ADC.The other option is to bias the mid-point of the differential input to Vref/2 instead of GND and have a 5v-GND supply on the analog side. This would simplify the power supply of the overall circuit. Are there any other considerations to going this route that a beginner might not have considered?

author: Andy Chee
author_rank: Super Contributor
timestamp: September 19, 2024, 10:48:07 am
content: What is the analog signal going into the ADC? Microphone audio? Air flow/pressure sensor? Light sensor? Magnetic field?

author: bluespider
author_rank: Contributor
timestamp: September 19, 2024, 12:50:14 pm
content: Currently a geophone (magnet moving in a coil), but will possibly add a hydrophone (piezoelectric) later - will require a high-impedance input.

author: Andy Chee
author_rank: Super Contributor
timestamp: September 20, 2024, 04:43:48 am
content: In the interests of preserving low frequency fidelity, I would be inclined to retain any existing DC coupling, and keep the bipolar power supplies.However, I'm not familiar with geophones nor the typical data it generates, so I'm making some assumptions about your frequencies of interest.If you do decide to go with Vref/2, it is important that the input AC coupling capacitor has enough low frequency response, otherwise your data may be distorted.

author: bluespider
author_rank: Contributor
timestamp: September 20, 2024, 12:04:20 pm
content: For our purposes >2Hz would be fine. I've attached the current input circuit (minus the clamping diodes) and an example given in a datasheet for a different (but similar) ADC - which shows the alternative.
Split rail power supply suggestions  - Page 1
Forum section: electronics / beginners

author: Jwillis
author_rank: Super Contributor
timestamp: December 03, 2017, 01:05:40 am
content: Hello folks.I've been working on a TOA MCX 106 power mixer that looked like it was struck by lightning.I've managed to repair most of it and it works great so far.Now I need to repair the Dolby X on the cassette recorder but I need to supply both positive and negative to do the repairs and calibrations. Up until now I have been getting by on a home brew supply for most of my projects but now I need a fairly decent adjustable split rail supply that won't cost me any limbs or organs.And I can't tell for sure if some of the units on EBay are true split rail or not, just because they have three terminals. I would venture to say they are not .It would be nice to get at least 30 to 50 volt for later projects but 20 volt would do for now.I try to avoid cheap switchers,for they can more trouble then they're worth so linear would be best.Any ideas ?

author: Brumby
author_rank: Unknown
timestamp: December 03, 2017, 02:15:48 am
content: If you don't need the split supply to have tracking capability (where one adjustment changes both +ve and -ve voltages at the same time) you can simply get a second supply with floating output and just connect them together.This video gives a great insight...If you happen to have a plugpack with the right voltage and current capacity for one of the rails, you can use that. It's output will be floating.

author: Jwillis
author_rank: Super Contributor
timestamp: December 03, 2017, 02:29:16 am
content: Well bummer I was hoping I could just get one.

author: buck converter
author_rank: Regular Contributor
timestamp: December 03, 2017, 03:36:54 am
content: Why not one of thesehttp://r.ebay.com/fSq0B6

author: Brumby
author_rank: Unknown
timestamp: December 03, 2017, 04:03:06 am
content: Quote from: Jwillis on December 03, 2017, 02:29:16 amYou certainly can. There are plenty out there.I was just offering some less expensive alternatives.

author: Brumby
author_rank: Unknown
timestamp: December 03, 2017, 04:07:34 am
content: Quote from: buck converter on December 03, 2017, 03:36:54 am30V 2A dual supply with selectable configuration and tracking - plus a third output of 5V 3A.Used and with analogue metering, but nonetheless quite useful.(Note: I have no personal experience with this brand)

author: Jwillis
author_rank: Super Contributor
timestamp: December 03, 2017, 04:12:21 am
content: Quote from: Brumby on December 03, 2017, 04:03:06 amThank you Brumby for helping understand how the idea works .Its helping with the search.Quote from: buck converter on December 03, 2017, 03:36:54 amYa .That looks like it would work.looks to be based on the HY3005F-3 design, like the Mastech and Dr Meter.
Split rail power supply - Page 1
Forum section: electronics / beginners

author: KBJ
author_rank: Newbie
timestamp: May 18, 2019, 10:54:38 am
content: I am currently designing a power supply system where i need 3 voltages i.e 3.3v,2.5v and -2.5v. for 3.3v i'm using a MIC5504-3.3YM5-TR. For the bipolar voltages i have planned to use a charge pump of 5v and use a split rail power supply. The entire system uses a 3.7v lipo battery. The problem i'm facing is ground reference. There is a virtual ground from the split rail power supply and 3.3v LDO has a ground. Is implementing such a system is possible if so how to connect the ground and virtual ground?

author: Audioguru
author_rank: Super Contributor
timestamp: May 18, 2019, 03:44:24 pm
content: Many linear amplifiers that use a split supply can be biased at half the supply voltage and use coupling capacitors to work perfectly with a single supply.

author: Zero999
author_rank: Super Contributor
timestamp: May 18, 2019, 08:51:18 pm
content: Awhile ago, Audioguru did schematic showing the inverting and non-inverting op-amp configurations: both DC and AC coupled. Here's my version, showing the differential configuration too. The recommended resistor values are selected to ensure the DC impedance seen by the inputs are virtually equal and is important for a bipolar op-amp, with high bias currents.

author: mariush
author_rank: Super Contributor
timestamp: May 18, 2019, 09:17:31 pm
content: How much current on each rail ?How accurate must the 2.5v and -2.5v be?If the current is low on 2.5v, you could get that simply by adding a diode after the 3.3v ... a basic `1n4001..1n4007 will have a forward drop of 0.7v..0.8v at even 50-100mA ... so 3.3v - 0.7v = ~ 2.6vYou could get a basic charge pump regulator like MAX1720 to invert the 2.5v and you get -2.5v if you only need up to 50mA or so :https://www.onsemi.com/pub/Collateral/MAX1720-D.PDFThere's also regulators like AP3427 which have 2 outputs, so you can use one chip to create both 3.3v and 2.5v with higher efficiency:https://www.diodes.com/assets/Datasheets/AP3427M.pdf

author: MosherIV
author_rank: Super Contributor
timestamp: May 18, 2019, 10:19:44 pm
content: Quoteno, it is not possible to mix a 0V with virtual ground/0V.ALL voltages are with reference to a 0V !As Mariush has suggested there are special ASICs that convert a positive voltage to a negative voltage.I was going to suggest the old classic 7660, which converts a positive toltage to a negative voltage.Hope that helps.
Split supply from Rigol DP832A - Page 1
Forum section: electronics / beginners

author: Legion
author_rank: Frequent Contributor
timestamp: April 02, 2014, 05:14:05 pm
content: I'm working with opamps and need both positive and negative rails. I have a DP832A. Do I just use two channels and wire the second channel backwards to act as a negative supply? Or do I link the two channels somehow? I've seen people connect the positive output of one channel into the negative of the second. But I don't understand what they're doing and would like to avoid blowing up my DC supply.

author: Fsck
author_rank: Super Contributor
timestamp: April 02, 2014, 05:30:41 pm
content: ie: set channel 1 to 15V, channel 2 to 15V[Chan1 -] [Chan1+]-----[Chan2-] [Chan2+]^neg rail----^ ^--"0V"--^ ^pos rail -----^^-----[-15V]--^ ^---[+15V]---^you end up with a floating virtual common reference point "0V aka "ground" " between the two rails at the Chan1+ and Chan2- (which you need to connect together) terminals.if you measure between Chan1- and Chan2+, you should get 30Vthis works because the channels are floating (from earth) and isolated (from each other).**** For this power supply, isolation is: Chan1 ||| Chan2 & 3 **** aka, Chan2 & 3 have a common "-" terminal (per specs)which means you can set a small negative rail or asymmetric +/- rails using Chan2&3:[Chan 2/3-] [ Chan 3+ ] [Chan2+]^----neg rail ----^ "0V" ^----pos rail--^^---( 0V-5V )^ ^-----( 0-30V)--^but with restriction of:^-------- (0-30V)---------------^Both of these are basically the electrical equivalent of a changing of basis or moving the origin. (math&physics)Since voltage is potential difference between two points, it's technically undefined without a set reference point.

author: Legion
author_rank: Frequent Contributor
timestamp: April 02, 2014, 06:24:01 pm
content: Thanks! That worked.

author: Legion
author_rank: Frequent Contributor
timestamp: April 02, 2014, 06:51:29 pm
content: Actually, I'm getting some strange behavior. The positive rail is outputting 6V which is what I set. But the negative rail is only putting out -1.9V, even though it's set to -6V. The positive rail shows almost no current output (2mA) but the negative rail shows 104mA.I'm attempting to make a basic inverting amp with an LM741. Only thing missing from the circuit schematic are the supply rails which are supposed to be +-6V and the two offsets which are both tied to ground.I've got my FG hooked up to Vin. My scope is hooked up to Vouton channel 1 and Vinon channel 2.Why won't the negative supply output -6V?
Splitting ground planes or not in power application - Page 1
Forum section: electronics / beginners

author: anvoice
author_rank: Frequent Contributor
timestamp: July 02, 2025, 08:04:43 am
content: I have a motor driver circuit in the works, and was wondering if it's better practice to split the power and signal grounds (to be connected via a thin bridging trace) or just use a single ground plane? Design is likely going to use a 4-layer PCB, not 6, so I can't dedicate 2 layers to ground. If ai understand correctly, possible EMI induced by the motor current is my main possible issue, and I've heard some encourage splitting grounds, while others say never to split them.

author: thm_w
author_rank: Super Contributor
timestamp: July 02, 2025, 09:48:08 pm
content: Single ground plane.https://www.eevblog.com/forum/beginners/split-ground-plane-to-do-or-not-to-do/https://www.eevblog.com/forum/beginners/split-vs-common-ground-plane-for-switching-converters/

author: anvoice
author_rank: Frequent Contributor
timestamp: July 04, 2025, 05:40:12 am
content: Sounds good, that seems to be the prevalent advice I'm getting from different sources today.

author: wraper
author_rank: Unknown
timestamp: July 04, 2025, 06:49:12 am
content: Splitting the grounds (unless galvanically isolated) is the easiest way how to make something that works fine into something that has EMI and hard to catch intermittent problems.

author: Terry Bites
author_rank: Super Contributor
timestamp: July 04, 2025, 12:30:24 pm
content: The anti slotters are probably right.Stategic decoupling can also modify current paths.
Splitting wires - Page 1
Forum section: electronics / beginners

author: shaiss
author_rank: Contributor
timestamp: September 03, 2016, 04:15:15 am
content: I have 1 open 12v rail coming of my PSU. I'd like to use it for LEDs, fans, and some other small bits. I could pigtail the cables but that would be ugly and probably a bad idea.So im trying to learn what's the best way to take one v+ wire and a gnd to a rail. Similar to what I do on my breadboards.Would a terminal block do this? From what I read on Amazon didn't sound like it would.Any guidance on what this would be called and links would be greatly apprilicjsted!

author: rstofer
author_rank: Super Contributor
timestamp: September 03, 2016, 05:32:44 am
content: Barrier terminal block with jumphttps://www.jameco.com/shop/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&freeText=barrier%20terminal%20block%20jumper&search_type=jamecoall
SPO-256 AL2 voice synth chip needs tons of resetting to work - Page 1
Forum section: electronics / beginners

author: newastrocity
author_rank: Contributor
timestamp: April 27, 2018, 10:15:25 pm
content: Hi all,I have followed the project here to make a voice synthesizer:http://www.instructables.com/id/Arduino-Vintage-Speech-Chip/(Including having to make my own colpitts oscillator because I didn't have the correct oscillator, just the crystal...)It is working (except I need to add an amp), but like the instructables says he encountered, I need to reset my project upwards of 20 times rapidly to get the "Hello world" sound to come out, or else it is just static and weird noises. Is there a component I can add to this project so that it will work everytime on boot?Thanks and any help greatly appreciated, I assume some sort of capacit-whatsit somewhere could solve this. I am feeding the chip a solid 5VDC (more than one PSU, and measured at the chip).

author: Ian.M
author_rank: Super Contributor
timestamp: April 27, 2018, 10:50:08 pm
content: I'd start by putting the Arduino in control of the SP0256's /Reset (2) and /Sby_Reset (25) pins. Tie the two SP0256 resets together, connect them to an unused Arduino I/O, and in your sketch's setup() function, set that I/O as an output and set it low for 100ms then set it back high. The 100ms is much much longer than the Archer SP0256 datasheet's minimum reset pulse length of 100us because after powerup, you need to be certain the power supply is stable before releasing the SP0256 from reset. If you want to reset it during operation a 1ms low going reset pulse should be sufficient.Now you've got me inspired to dig out a SP0256 from the box of bits I got when Tandy UK went under and see what I can get out of it.

author: newastrocity
author_rank: Contributor
timestamp: April 27, 2018, 10:57:21 pm
content: That answer makes a ton of sense, I will try that when I get home and report back my results. Thanks!

author: newastrocity
author_rank: Contributor
timestamp: April 27, 2018, 10:58:11 pm
content: Oh, and if you do get your chip working, post it up, I have a weird obsession with these dedicated 70's/80's chips that can be mimicked with microcontrollers, I have a weird passion for this oldschool stuff.
SpO2 monitor sensor - please help me understand - Page 1
Forum section: electronics / beginners

author: solar_pi
author_rank: Newbie
timestamp: January 07, 2022, 01:23:51 am
content: Intro story: I spent way too much time in the hospital with my newborn over the last weeks. Now he's home so all good. As I was in the hospital I noted SpO2 monitor connected to his foot. These run on a long cable to a head-unit, which is a clever device. The sensor itself is a disposable unit, which (with permission) I took.To my knowledge principle is simple: IR + Red led + a photo-diode.After a small disassembly I noted that there are few elements I did not expect / understand.Cable is set up as follows:- external shielding / silver color- red/black power for diode(s) in said shielding- another white cable which after stripping down has:Red/black wired LED - I guess it has Red + IR build inGreen/White - photo diode?Photo diode was wrapped in copper which was connected to 2 separate shielding

author: cdev
author_rank: Super Contributor
timestamp: January 07, 2022, 02:07:48 am
content: i think the most popular brand contains a UART connection, or something like that. But I dont know how to use it.

author: solar_pi
author_rank: Newbie
timestamp: January 07, 2022, 10:59:35 am
content: Thanks. The paper I read explained just that and some math behind it. I am curious about the engineering part of the sensor I got now as well. I see that my last night post does not have the pictures and the full text. I will update it later on!
Spot light- led strobe feature removal  - Page 1
Forum section: electronics / beginners

author: Gillett02
author_rank: Newbie
timestamp: May 25, 2022, 07:03:29 pm
content: Hi all,I have fitted some spot lights to my car, they have two light settings a full beam and a low beam/ all day running light.The full beam works perfectly fine. However, the low beam seems to have a strobe feature which I want to bypass. The strobe feature isn’t on all the time it alternates from being a solid light to strobe every time you turn the light off and then back on. I have attached and image of the circuit, the bit highlighted in yellow is the low beam and the red circle is the power supply for the low beam.Is there an easy way to bypass the strobe feature so it will always show as a solid light?Thank you in advance!

author: thm_w
author_rank: Super Contributor
timestamp: May 25, 2022, 11:23:22 pm
content: Can you take a closer photo of the two small 8 pin ICs, or read the part numbers off them.

author: james_s
author_rank: Super Contributor
timestamp: May 26, 2022, 12:52:57 am
content: It seems like the Chinese are absolutely obsessed with stupid strobe modes, especially on flashlights but this is even worse.

author: aargee
author_rank: Frequent Contributor
timestamp: May 26, 2022, 02:39:36 am
content: Yes, who the heck wants the flashing option so accessible!Does it have 12V onto the light all the time? If so, a relay to turn it off completely (for a short time?), that way it will always have the first option... and the flange broken from the inductor is floating around the bottom there, not that it will affect operation.

author: Gillett02
author_rank: Newbie
timestamp: May 26, 2022, 10:28:03 am
content: Bottom 8 pin chip

author: Gillett02
author_rank: Newbie
timestamp: May 26, 2022, 10:29:15 am
content: Top 8 pin chip

author: Gillett02
author_rank: Newbie
timestamp: May 26, 2022, 10:33:38 am
content: Quote from: aargee on May 26, 2022, 02:39:36 amThe light only has a 12v feed when the lights are turned on, it seems to swap from whatever mode it was last on regardless of how long you wait.( it doesn’t default to particular mode )

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 26, 2022, 12:32:38 pm
content: There're two power wires (red/yellow), so it might be something else, have a look under the board.Those two 8-pin ICs seem simple led current drivers.Take a DMM and measure the voltage between black and red/yellow when it's strobing.If the voltage goes on and off, then there's something else.
spot welder cable terminal - Page 1
Forum section: electronics / beginners

author: Sigi_cz
author_rank: Newbie
timestamp: December 03, 2022, 10:53:39 pm
content: Hi all,I want to make better cables for my chinesium spot welder and for that I need to buy the connectors/ terminals.At first glance the original one looks like 8 mm bullet or EC8 connector; however, it's longer and crimped.After a lot of googling I did found this one EC8 image with exactly what I need.But all EC8 connectors, I found for sale, look different and have the hole for soldering so they are not meant for crimping (with hydraulic hex crimpers).As English is not my native language, maybe my search terms are not correct?Anyway. Any idea where to get the 8 mm bullet crimp connectors?

author: BillyO
author_rank: Super Contributor
timestamp: December 04, 2022, 03:02:17 am
content: Standards in spot welding are few and far between. Most spot welding cables use some form of bolt-on attachment, but there are many other methods too. I'd see if I could find some DIY welding forums. All that said, soldering should not be an issue if the equipment duty cycle is adhered to. If the cables are big enough, something else would let go before the solder melted.BTW, the Chinese make some of the best spot welding equipment on the planet. They are also masters of supplying a market. Any market. So they will gladly provide stuff to a market that does not value their hobby/job/etc. enough to buy the quality they really need then complain about the junk they bought.

author: woodchips
author_rank: Frequent Contributor
timestamp: December 05, 2022, 08:15:37 pm
content: A spot welder uses a couple of volts at hundreds of amps, perhaps the problem is using any type of cable? Most spot welders use rigid arms, with the absolute minimum of enclosed area inside the arm loop.Welders use Dinse connectors, these are a sort of bayonet connector, but excellent for high current use. Not so great on low voltage because made from brass, and the current rating means they are large.Alternatives are connectors for fork lifts and similar.

author: Sigi_cz
author_rank: Newbie
timestamp: December 10, 2022, 08:01:54 am
content: So no one has an idea where to get that connector?

author: BillyO
author_rank: Super Contributor
timestamp: December 10, 2022, 01:55:37 pm
content: "I'd see if I could find some DIY welding forums"
Spot Welder Circuit ?? - Page 1
Forum section: electronics / beginners

author: jijcomm
author_rank: Newbie
timestamp: March 04, 2018, 06:13:10 pm
content: Hi all,I am a beginner in electronics, and I would build a simple spot welder for 18650 batteries.Can this simple circuit do the job in a good manner.The capacitor is charged with closed interrupter, when it's full the interrupter is opened, then it is disharged through the transformer with the second interrupter (it can be a relay or a Mosfet).and thanks

author: Cliff Matthews
author_rank: Unknown
timestamp: March 04, 2018, 09:45:51 pm
content: No it won't work. Transformers pass AC through induction (a collapsing and expanding field). Your source on the left is drawn as AC passing through a diode bridge rectifier to make DC. (edit) Kasyan TV's channel has a number of DIY battery spot welder video's to watch:Yellow high-lighted battery can be an old car battery and the 555 sets the pulse width to send to the driver / output mosfets.

author: FrankE
author_rank: Regular Contributor
timestamp: March 05, 2018, 06:30:16 am
content: I would start with projects with much lower energy density.I've worked 11kV and I'm shit scared of soldering lithiums, welding and generally things that spark .

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: March 05, 2018, 08:34:20 pm
content: Interesting video Cliff Thanks for sharing.Chris
Sprague Transistor Curve Tracer - Page 1
Forum section: electronics / beginners

author: nancysand
author_rank: Newbie
timestamp: November 10, 2017, 12:31:41 am
content: Hello, I am not sure this is the right place to post this. We are selling off some old equipment of my husbands includingSprague Transistor curve tracerOcean Applied Research Corp Automatic Direction FinderI have absolutely no idea as to the value of these pieces of equipment. The second one I found reference of on another site. Refurbished $1k. However, these piece work but not refurbished.Anyone who has any knowledge of these pieces would be appreciated.

author: danadak
author_rank: Super Contributor
timestamp: November 10, 2017, 02:08:16 am
content: You should list the model numbers of the equipment. Also if youhave the manuals for the equipment state that., titles, pub date.Also there is a forum section for selling equipment where thispost belongs.https://www.eevblog.com/forum/buysellwanted/Regards, Dana.

author: nancysand
author_rank: Newbie
timestamp: November 10, 2017, 02:56:57 am
content: Thank you I wasn't trying to sell, I was trying to find out if they are worth anything. If not they will get scrapped
Spreadsheet for simulating aliasing - Page 1
Forum section: electronics / beginners

author: calzap
author_rank: Frequent Contributor
timestamp: April 08, 2014, 12:50:39 am
content: Attached is an Excel 2007 spreadsheet that simulates aliasing that sometimes occurs with digital oscilloscopes. I created the spreadsheet so I could understand the phenomenon better. Aliasing is when a waveform appears on the display that is of lower frequency than the input waveform and can happen when the sampling frequency of the scope is lower than the frequency of the input waveform. The scope is snatching samples from different cycles of the input and constructing a lower frequency waveform from the samples. The spreadsheet is setup for a sine wave, but can easily be changed to another type. There are two examples in the spreadsheet. One is the obvious case where the sampling interval is an integer or half-integer multiple of Pi times the period of the input signal. At least in this case, the displayed peak-to-peak amplitude is correct even though the frequency is wrong. The other example is where the sampling interval is an out of phase factor times the period of the input signal. In this example, both the peak-to-peak amplitude and frequency are wrong. There is a good discussion and instructive graphs of aliasing on Wikipedia.Mike in California
Springloaded linear potentiometer - Page 1
Forum section: electronics / beginners

author: Sudo_apt-get_install_yum
author_rank: Regular Contributor
timestamp: June 11, 2019, 10:53:24 am
content: Im working on a project where i need to measure a small amount of linear movement (a few millimeters).I had a few laying around but cant find a supplier for them does anybody know of any company who produces or supplies these types of potentiometers?I would like to hear if anybody has a better solution for measuring very small movements in one axisThe below image is of the linear potentiometer.

author: AndyC_772
author_rank: Super Contributor
timestamp: June 11, 2019, 12:11:06 pm
content: What level of accuracy do you need? How fast is your target moving?

author: Sudo_apt-get_install_yum
author_rank: Regular Contributor
timestamp: June 11, 2019, 12:16:40 pm
content: The speed is variable but it’s never more than a few millimeters per second. The accuracy should be somewhere between 1/10mm - 1/100mm.

author: mariush
author_rank: Super Contributor
timestamp: June 11, 2019, 12:27:36 pm
content: Maybe the same idea behind precision rulers/calipers...Maybe you can repurpose a mouse sensorMaybe you can do some infrared led and detector annd measure change in light as object movespermanent magnets on partt, hall effect sensors on botom?

author: mikerj
author_rank: Super Contributor
timestamp: June 11, 2019, 04:07:46 pm
content: https://www.variohm.com/images/datasheets/KTP_Position_Sensor_%201807_E.pdfhttps://www.megatron.de/en/category/potentiometric-position-sensors.html

author: Sudo_apt-get_install_yum
author_rank: Regular Contributor
timestamp: June 13, 2019, 07:08:52 am
content: Thanks for the advice, I'll look into the caliper solution!

author: TERRA Operative
author_rank: Super Contributor
timestamp: June 14, 2019, 04:16:04 am
content: What about a slider pot like used in audio mixing desks?
SPS Programming (EN: PLC) & CODESYS known outside of Germany (DACH)? - Page 1
Forum section: electronics / beginners

author: davidleverett30
author_rank: Contributor
timestamp: July 30, 2014, 09:16:46 am
content: Hi folks,I have been searching for a student job/internship in Germany, Stuttgart. I am looking for positions where I can work with Electrical Engineers (or of that nature).While looking for a position,I`ve come across "SPS Programming" (English "PLC Programming".) a hell of alot.Also knowledge of "CODESYS"??Has anyone outside seen this outside of Germany (DACH)??http://en.wikipedia.org/wiki/CODESYShttp://de.wikipedia.org/wiki/Codesys