hybridfree/eevblog-posts huggingface dataset:
sanity check - window comparator - Page 1
Forum section: electronics / projects

author: poorchava
author_rank: Super Contributor
timestamp: December 30, 2013, 12:47:44 am
content: Hey,I've been designing a circuit that needs some means of protection from supply voltage being either too high or too low. I came up with something like this:The circuit is supposed to cut off the power supply rail if it's below 20V or above 30V. High accuracy is not needed.Obviously the mosfet is first with reasonable Rds from LTSpice library and resistor values are totally out of my ass. Spice says it will work, but maybe I'm missing something obvious?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: December 30, 2013, 12:58:15 am
content: Hi,I can see a few features of this circuit:1) You have a temperature dependency. The Vbe threshold of the transistor will reduce by 2mV degree C. This may be o.k. because you don't require precise thresholds.2) The other feature that I see is that you could end up with the MOSFET in the Linear region. This could mean high dissipation in the MOSFET. some kind of hysteresis is required so that the MOSFET is on or off.Linear Technology has an IC that implements this function. Have a look at the LTC4365.http://www.linear.com/product/LTC4365Regards,Jay_Diddy_B

author: nctnico
author_rank: Super Contributor
timestamp: December 30, 2013, 02:12:02 pm
content: I'd use at least a real comparator like the LM339 (quad) or LM393 (dual). Besides that you'll need a clamping device to limit voltages (=blow a fuse) beyond the supply range of the components.

author: dannyf
author_rank: Super Contributor
timestamp: December 30, 2013, 02:55:56 pm
content: It will work, better with R3/R7 replaced with appropriate zeners and the associated resistors resized.

author: poorchava
author_rank: Super Contributor
timestamp: December 30, 2013, 11:34:54 pm
content: Quote from: nctnico on December 30, 2013, 02:12:02 pmThat's the main problem. A TVS is already in place, but it has a downside of blowing up when input voltage exceeds clamping threshold for longer periods of time. The device has to be flame-safe and all the magic smoke has to be kept inside no matter what.Quote from: Jay_Diddy_B on December 30, 2013, 12:58:15 amThe temperature dependancy of junction voltage drop is not an issue. I am aware of the possibility of the mosfet ending up in linear region, but I could come up quickly with some simple way of adding hysteresis. I will work on that and see what I can come up with.The LT chip seems like an ideal solution, but it's rather expensive. But it made me search for similar devices. What do you think about LM5060?http://www.ti.com/product/lm5060-q1Seems to do pretty much the same thing aside from reverse polarity protection, which is not required in this case (diode bridge before the circuit).

author: nctnico
author_rank: Super Contributor
timestamp: December 31, 2013, 12:59:44 am
content: Quote from: poorchava on December 30, 2013, 11:34:54 pmThen use a bigger TVS and a PTC (self resetting) fuse. I'd use through-hole parts for both.
SATA Port Samsung SSD Replacement - Page 1
Forum section: electronics / projects

author: nhoj_yelbom
author_rank: Contributor
timestamp: January 06, 2014, 12:02:07 am
content: i got a sweet deal on a 750gb samsung ssd, with a broken sata port. i have looked for a replacement, and having a hard time. any help appreciated!some that may be close, looks like sata port inverted on the ssdhttp://www.digikey.com/product-detail/en/5622-6309-ML/3M5555-ND/1207097http://www.digikey.com/product-detail/en/0877030001/WM19111-ND/1499168picture of board

author: Alana
author_rank: Frequent Contributor
timestamp: January 06, 2014, 12:33:41 am
content: I think the simplest solution would be to get laptop hdd for scrap, connector seems to be the same.

author: nhoj_yelbom
author_rank: Contributor
timestamp: January 06, 2014, 12:34:43 am
content: Quote from: Alana on January 06, 2014, 12:33:41 ami have a pile of them, they all have extra shunt port and are too different.

author: Stonent
author_rank: Super Contributor
timestamp: January 06, 2014, 01:50:51 am
content: That looks like a SAS connector not SATA.

author: Stonent
author_rank: Super Contributor
timestamp: January 06, 2014, 01:56:22 am
content: SATA drives will physically plug into a SAS cable and usually work but at a reduced speed. SAS drives won't fit a SATA cable because there's a lot more to the SAS protocol that the SATA controller can't deal with.

author: nhoj_yelbom
author_rank: Contributor
timestamp: January 06, 2014, 02:06:45 am
content: Quote from: Stonent on January 06, 2014, 01:56:22 amfor sure a sata 6gbps, not SAShere is a link to the exact drivehttp://www.newegg.com/Product/Product.aspx?Item=N82E16820147248
Saturday Night's fun time: 9V battery tester - Page 1
Forum section: electronics / projects

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 05, 2014, 02:00:52 am
content: Sure I could have bought something, but from work I get a lot of 9V batteries, and I wanted a fast, repeatable, accurate, adjustable tester that puts a little load on the battery. Most of the batteries are good-enough for use in assorted projects, but some are dead as rocks.I decided to go with a full-wave bridge because it would save time to be able to ignore polarity. And then because I have this thing about making circuits really small, I thought I'd go with surface-mount components too. Plus I want to test the sizes of the footprints I made in the KiCAD library. I had a 3.3V SMD regulator in the drawer, and I had bought some SOT-23-5 op-amps. I forgot I did actually have a 50-ohm SMD resistor, but I used a through-hole for the red "on" LED.In all it works pretty good. The red LED comes on when contact is made with nearly any battery (e.g. more than about 5 or 6 volts, I guess.) The green LED comes on when the voltage is over about 7.5V. (I measured an arbitrary battery at 8.37V then measured the 10K/1K divider and got 0.609V, so my ratio is 0.073 or so, counting the rectifier voltage drop, so with the pot set to divide out 0.55V or so, that's 0.55V/0.073 = 7.5V.)Anyway,... here's the schematic and pictures of the finished circuit. The acrylic conformal coating is drying which is why there's tape on the battery terminals.

author: calexanian
author_rank: Super Contributor
timestamp: January 05, 2014, 03:47:39 am
content: Fancy..... I just have a pair of cheap multimeter probes with a 300 ohm resistor soldered in across them half way down the leads.

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 05, 2014, 12:35:49 pm
content: Quote from: calexanian on January 05, 2014, 03:47:39 amI should make one of those too, but I also have to get through over 200 batteries ...Maybe I'll test the ones that flicker that way (e.g. with no hysteresis, turning on the green LED can sometimes drop the battery voltage below the threshold, turning off the LED, letting the voltage come back up, and so on.)

author: Jon86
author_rank: Frequent Contributor
timestamp: January 05, 2014, 01:23:54 pm
content: Great little project, how much current does the tester draw from the battery?

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 05, 2014, 08:41:37 pm
content: Quote from: Jon86 on January 05, 2014, 01:23:54 pmThanks. I measured about 40mA; 45mA if the battery is good (both LEDs lit).
SAVE WWV Time and Standard Frequency Station in the US - Page 1
Forum section: electronics / projects

author: LaserSteve
author_rank: Super Contributor
timestamp: September 12, 2018, 04:02:27 pm
content: The director of NIST wants to sunset WWV, WWVH, and WWVB time stations in 2019.. Bye Bye self setting clocks...Petition to save WWV..https://petitions.whitehouse.gov/petition/maintain-funding-nist-stations-wwv-wwvhNon Americans can sign....Steve

author: drussell
author_rank: Super Contributor
timestamp: September 12, 2018, 04:42:59 pm
content: https://soylentnews.org/article.pl?sid=18/08/26/1548226

author: NivagSwerdna
author_rank: Super Contributor
timestamp: September 12, 2018, 05:13:30 pm
content: That sounds like a business opportunity.I remember once reading an article about someone that had an external antenna and then distributed the signal to low power repeaters near the clocks. A GPS version would be quite do-able.I use DCF77 and to a lesser extent MSF60 but to be honest they really struggle with noise around PSUs, monitors and PCs.http://ka7oei.blogspot.com/2013/03/getting-atomic-wwvb-clocks-to-work.html?m=1

author: Tom45
author_rank: Frequent Contributor
timestamp: September 13, 2018, 07:45:40 pm
content: I just checked and there are less than 20,000 signatures on the petition. Far short of the 100,000 apparently needed in the next two days.

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2018, 08:40:20 pm
content: Quote from: NivagSwerdna on September 12, 2018, 05:13:30 pmThey already did the business opportunity by adopting a patented "improvement" to WWVB stopping existing phase locked receivers from operating and preventing others from releasing new receivers.https://en.wikipedia.org/wiki/WWVB#Phase_modulation
Saving money by simulating industrial sensor datastreams - Page 1
Forum section: electronics / projects

author: wobbly
author_rank: Regular Contributor
timestamp: August 23, 2025, 04:50:01 pm
content: I've been trying to teach myself all about PLCs and ladder logic. I found myself wanting to put the knowledge into action using real sensors and analog input modules. That is until I saw the price of them!My PLC has a serial port which supports both ASCII and Modbus communication methods. And the ladder logic allows access to this for importing sensor data from remote systems.So I set out to build a small simple device that can simulate some arbitrary piece of industrial equipment, such as a water tank or a conveyor belt or a pneumatic actuator etc.My go-to item for projects like this is an AVR microcontroller. I programmed an ATMega328P with some simple code to send out 12 bytes over the serial port. 3 bytes of prefix "PS@" and 1 byte of suffix "#" with 8 bytes of simulated sensor data in between. In the logic analyser screenshot below you can see the whole stream. "A" and "B" are two of the sensor readings.The ladder logic checks the incoming data for this packet format and then all 8 data readings are transferred into the PLC's memory at specific locations - from which they can be used directly as part of the main PLC program!The really nice thing about this is that I can program the AVR to simulate the behaviours and faults of real machinery in order to test out different parts of my ladder logic programs!Also, I added a few opto-couplers so I can interface directly with the physical IO terminals on the PLC itself, which gives me some more options.The ladder logic screenshot shows the PLC correctly parsing the serial data and capturing the "A" as 65 in the lower left corner.The PLC is anAutomation Direct "C0-00DR-D"which has eight sink-source 24V inputs and six light-duty relay outputs.This gadget will allow me to explore more elaborate LL programs without spending $$$ on real hardware!

author: Terry Bites
author_rank: Super Contributor
timestamp: August 23, 2025, 07:08:04 pm
content: A "process calibrator" is the thing you want, they emulate automation signals.Branded calibrators cost an arm and a leg but I've seen cheap ones on Aliexpress. Keep an eye out on Ebay.It would be an interesting project to DIY one.www.aliexpress.com/w/wholesale-process-calibrator.html?g=y&SearchText=process+calibrator&pr=-100
Sawtooth Oscillator Waveform - Page 1
Forum section: electronics / projects

author: dotcom.com
author_rank: Contributor
timestamp: May 05, 2023, 08:40:11 am
content: I am currently working on a sawtooth oscillator and I cant seem to get the shape right. I'm not sure if it's a component issue. I am trying to use this to implement into a 10V boost converter.EDIT:I lowered my capacitance and R5 values and was able to generate a sawtooth. However I'm not sure how good it is especially at the start of it. I Attached the new screenshot of the transient and schematic below the original

author: Avelino Sampaio
author_rank: Frequent Contributor
timestamp: May 05, 2023, 09:53:28 am
content: Watch the video of our participant W2aew

author: wasedadoc
author_rank: Super Contributor
timestamp: May 05, 2023, 02:30:21 pm
content: Quote from: dotcom.com on May 05, 2023, 08:40:11 amWhy do you want to use that to implement a boost converter?

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 05, 2023, 03:59:18 pm
content: QuoteThe schematics is off. Follow the one on the youtube video. It uses a more precise current generator to have the linearity you wanted.

author: dotcom.com
author_rank: Contributor
timestamp: May 05, 2023, 09:02:04 pm
content: Quote from: wasedadoc on May 05, 2023, 02:30:21 pmI am making this oscillator to meet certain design parameters of my boost converter. It is a part of my control scheme as I also have to create PWM, error amplifier and maybe a compensation network.Where my parameters are:a) Input voltage Vin=5Vb) Maximum load current = 250mAc) Output voltage ripple < 50mVd) LIR under 20%e) Clock frequency=100KHzf) Power efficiency >90%Amplifier and switches must be implemented at transistor level.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 05, 2023, 09:14:04 pm
content: Seems this question has already been asked and responded onhttps://www.chegg.com/homework-help/questions-and-answers/b-justification-description-chosen-architecture-c-design-procedure-values-relevant-compone-q114095153

author: Someone
author_rank: Super Contributor
timestamp: May 05, 2023, 10:43:29 pm
content: Quote from: dobsonr741 on May 05, 2023, 09:14:04 pmCertainly smelled like homework. Discrete transistor design, LIR, fixed frequency ? completely non-realistic.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 05, 2023, 11:59:08 pm
content: Though I liked that it made me review the UJT oscillator, it's nice how the youtuber used a current source to linearize the sawtooth.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 06, 2023, 07:54:37 pm
content: Without even looking at the schematic (except for the 5V power supply rails):The rising flank is fairly lineair up to about 4V, and then it starts to taper off. Conclusion is that your current source needs about 1V of headroom to work properly, and you should switch your switch before your capacitor is charged to 4V.
SayoDevices Programmable Keypad - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: March 20, 2025, 05:00:14 pm
content: I just picked up one of these programmable keypads:https://vi.aliexpress.com/item/1005007096723667.html?spm=a2g0o.order_list.order_list_main.10.3b361802C68jFf&gatewayAdapt=glo2vnmIt seems to work fine, however the only way to program it (that I'm aware) is to use the online programmer.That's fine for today, however there is a strong possibility that online programmer will either cease to exist in the future or have a fee associated with it.Any chance an actual program (Windows or Linux) exists that will allow programming if said online programmer becomes unavailable?No luck contacting SayoDevices
SC1000 - scratch DJ controller with enclosure made from PCBs - Page 1
Forum section: electronics / projects

author: rasteri
author_rank: Contributor
timestamp: October 24, 2019, 06:43:29 pm
content: Hi, so I released this project ages ago but it just occurred to me the all-PCB construction might be interesting to you guys.Here's a video showing what it can do :A couple of pics of a finished unit :The enclosure consists of six PCBs screwed to two 3D-printed bars, and the jog wheel is another PCB. Here's a pic showing the internal construction :The rotational angle of the wheel is measured using a AS5601 magnetic rotary sensor, which detects the angle of a diametrically-polarized magnet dangled a few milimetres above it. The jog wheel is also capacitive-touch-sensitive to detect when the user is touching it, to simulate a motorized turntable (which would continue playing when the user is not touching the record).The code runs on an Olimex A13-SOM-256 system-on-module, which in turn uses an Allwinner A13 ARM Cortex A8 SoC, and runs a custom buildroot linux distribution.Another random thing I wanna mention is the use of the TE Connectivity 2108877-1 Micro USB connector, which is really robust and is happy to be mounted straight to a normal PCB. All other micro USB connectors I've seen really need to be mounted to their own little compliant/flex PCB and/or given additional reinforcement as part of the device enclosure (like in phones).More information and source code are on github -https://github.com/rasteri/SC1000
SC18IS604 SCLK input - does it have a resistor network on it? - Page 1
Forum section: electronics / projects

author: peter-h
author_rank: Super Contributor
timestamp: October 10, 2025, 10:49:11 am
content: I am getting a weird waveform on that signal, as if this chip had say a 10k +10k network on the clock input, so the signal floats to 50% of VCC when not driven.I've never seen any such thing and the DS doesn't mention ithttps://www.nxp.com/docs/en/data-sheet/SC18IS604.pdfOTOH, the SCLK input is seeing all sorts of clock speeds because the SPI is shared between a number of devices. The DS says 1.2MHz max but I am sending up to 21MHz to it. I wonder if that mucks it up? It should not do that because SPI can run at lots of clock speeds.Another aspect here is that my SPI (STM32F417) clock output may not be hard driven (to 0V) when no clock is being generated, so even a weak pullup will cause this behaviour.EDIT: testing suggests there is indeed just a pullup inside this stupid chip, of the order of 90uA. See here for the resulting problemhttps://www.eevblog.com/forum/microcontrollers/what-does-a-stm32f4-do-with-its-spi-clock-output-between-transactions/
SC6531  - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: December 12, 2015, 05:33:05 pm
content: HiDoes anyone have or know where one could find the datasheet for this device.http://www.spreadtrum.com/en/SC6531.htmlOpen the link above with firefox or internet explorer. Chrome does not work on my machine.I have contacted spreadtrum with no response yet. I have also googled for it without any success. My suspicion is that this might be a devices for which you will only get the datasheet if you are an OEM manufacturer.It is used in a US$6 Dollar phone (new) that bought.http://www.mintmobile.co.za/F1.aspx

author: amyk
author_rank: Super Contributor
timestamp: December 13, 2015, 01:42:11 pm
content: What you are looking for is called "SC6531 Device Spec".

author: Cicada
author_rank: Regular Contributor
timestamp: December 17, 2015, 11:46:25 am
content: Quote from: amyk on December 13, 2015, 01:42:11 pmThank you for this information. I was able to find some more info suing this search term.I cam across this blog. Very interesting to see how differnt the west's model is from the east's regarding IP and open sourcehttp://www.bunniestudios.com/blog/?p=4297
Scaling images using 2D Fourier transform - Page 1
Forum section: electronics / projects

author: Dukov Ahzrukhal
author_rank: Regular Contributor
timestamp: April 22, 2021, 03:28:59 pm
content: Hello everyone, I wrote a small program to scale images using the 2D Fourier transform, but the output I get does not look quite right. I did get a good result by scaling an image to its original size, but all other tests look wrong in various ways.While testing this I also realized that using this method to scale images is a terrible idea because it's very slow, but now that I've started I really want to finish this. If anyone can point out what I'm doing wrong I would greatly appreciate it.

author: Dukov Ahzrukhal
author_rank: Regular Contributor
timestamp: April 24, 2021, 04:33:16 am
content: I'm surprised nobody posted a reply, but that's ok, I figured it out anyways. Since it wasn't easy to find suitable examples I will post my fixed code in case someone else wants to try this.I got it working in two different ways: The code in test 7 is a complete hack, it relies on cropping the DFT image in an unusual way by keeping the corners of it. It's not the normal way to implement the 2D Fourier transform, but it does give the advantage of not having to deal with negative frequencies. The code in test 8 is what I think is the normal way to implement the Fourier transform, which has negative frequencies. The DFT image is cropped by keeping the center part of it. The zero frequency point is in the middle of the DFT image, and stuff to the left and up represents the negative frequencies. I wouldn't recommend that you use this code in your project as it is very slow, but it was certainly a very interesting and educational experiment to try.
Scanner controller IC - Page 1
Forum section: electronics / projects

author: Sísifo
author_rank: Newbie
timestamp: November 29, 2021, 07:55:17 pm
content: Hello! I'm new in this forum, so I don't know if this is the right place to ask, but I'm working on a project that involves developing a kind of scanner, akin to a standard flatbed scanner, but I have a problem finding a good IC for this purpose.I am looking for help regarding a viable ASIC for the purposes of controlling a linear CCD/CIS scanner.I have searched for hours but the only ones I could find are from a company called Genesys Logic (G1L25, GL128, GL3466...) but are not available anywhere not could I find a datasheet for them.The only other one is from TI (LM9833) but it is very dated (2001) and its parameters will not be sufficient for my application.Do you know of any other IC for controlling this kind of scanner? Or, if it doesn't exist, a CCD/CIS signal processor that is more recent?I could also settle for trying to implement this kind of function on an FPGA but It is less desireable. In the case you know where I could start in that regard, that would also be helpful.Thanks in advance!

author: TheMG
author_rank: Frequent Contributor
timestamp: November 30, 2021, 12:53:18 am
content: What about AD9822?
Scanning electron microscope - Page 1
Forum section: electronics / projects

author: Sweet
author_rank: Newbie
timestamp: September 15, 2018, 11:22:46 am
content: Hi everybodyI worked on various electronic system and produce prototype of them in the electronic field and by rely on empirical work.Recently I entered in Nano-electronic area which relates to development of electronic devices and components in a very small scale.My field of study is Nano-electronic and electronic but I like to work as an expert on development of SEM and I would like to gain experience and knowledge in this field. Indeed I am really determined to do this job with great enthusiasm and decided to choose my PHD course in manufacturing and design of this system.Right now I focused on studying the structure of electron microscope in order to reach a right insight and then I want to study SEM and its kinds to get familiar with all aspects of project for setting clear and precise goal to manufacture a prototype.I keep studying and researching regarding the path, in spite of all contempt I have faced so far.while tolerating all these is too painful, I am still delighted because it demonstrates the magnitude of the task I have been through.A very important point is that I don’t want to copy the similar system; moreover, I look for a great perception of designing and developing this system in a scientific way.would be so grateful if I know your point of view or recommend some books or articles which help me to have a better understanding.My email address : MohammadSajadi_68@yahoo.comhttps://www.linkedin.com/in/mohammad-sajadi-150010131/

author: ycui@eml.cc
author_rank: Newbie
timestamp: October 14, 2018, 02:06:41 am
content: The best way to do that is to work for a SEM manufacture. The general term is called e-beam. SEM is a portion of it, the other part is e-beam lithography. They are fundamentally the same. E-beam lithography has more advanced optical system.Three decades ago, this would be easier, as government was funding this type of research. Nowadays, there is no funding and professor won't teach you how to do that any more.Designing an electron microscope is not cheap. Just the simulation software package will run you $250k. It also costs you $10k+ for annual service. It will likely cost more than $5 millions to get a new design.

author: PointyOintment
author_rank: Frequent Contributor
timestamp: October 14, 2018, 05:59:27 pm
content: There are a few projectsherewhere people are building or modifying SEMs (or trying to).

author: iMo
author_rank: Super Contributor
timestamp: October 15, 2018, 11:15:54 am
content: A DIY "STM" could be easier to make at home.. No vacuum needed. And the VoltNuts here know well how to measure the small currents..https://hackaday.com/2015/01/13/cheap-diy-microscope-sees-individual-atoms/

author: PointyOintment
author_rank: Frequent Contributor
timestamp: October 15, 2018, 08:19:10 pm
content: STM is the easiest to DIY (low hundreds of dollars to a couple thousand at most, and a few hours' work), followed by AFM as a close second. Then SEM is third easiest (but much more difficult than STM & AFM), followed by TEM.
Scanning laser backscatter imager - Page 1
Forum section: electronics / projects

author: Kaptein QK
author_rank: Regular Contributor
timestamp: October 29, 2017, 09:23:29 pm
content: My latest project, making a image with a scanning laser and a single sensor:

author: ale500
author_rank: Frequent Contributor
timestamp: October 30, 2017, 12:45:40 pm
content: I find it quite impressive. It would be great if one could extract depth information too. (no audio for me)

author: _Wim_
author_rank: Super Contributor
timestamp: October 30, 2017, 08:59:14 pm
content: Nice! I like it!

author: Kaptein QK
author_rank: Regular Contributor
timestamp: November 04, 2017, 02:37:23 pm
content: Quote from: ale500 on October 30, 2017, 12:45:40 pmExtracting depth information (time-of-flight) is well above the capability of the hardware.It was just a proof-of-concept as I never have seen this done in the visible light spectrum, just in airport body scanners, with x-rays.Do not think it it will replace any known imaging technologies, thoughHas anyone seen similar use with visible light?

author: LaserSteve
author_rank: Super Contributor
timestamp: November 05, 2017, 05:34:22 am
content: Laser linescan has been done from recon aircraft since the early 1970s, starting with visible lasers and then moved elsewhere in the spectrum.As for hobby uses, there is a Russian web page some where of a guy scanning from an apartment.Steve

author: DTJ
author_rank: Super Contributor
timestamp: November 06, 2017, 06:51:44 am
content: That's quite neat.Years ago I worked on a Scanning Laser Opthalmoscope which was very similar but the beam was swept using galvos. Beam was trained into the eye and light reflected from the retina and internal structures was imaged.Using different wavelength laser diodes gave extra info that ophthalmologists could use to enhance imagining and make diagnostic decisions.Fun stuff!
Schematic feedback please - uC controlled lights, multiple pwr sources - Page 1
Forum section: electronics / projects

author: luxfx
author_rank: Contributor
timestamp: August 15, 2018, 07:45:17 am
content: Newb hobbyist here. If I can get this working, it will be the first project I intend to get a PCB printed for. It's a learning project, I'm playing with lower power, uC sleep modes, switching power regulator (not using prefab modules), and running from multiple power sources (i.e. once wall power has switched on, it will stop draining the battery).Let me stress the 'newb' partThe goal is to light up my workbench, which occupies a closet cabinet (it's nicer than it sounds). I want the light to fade in when I open the door. I'll be using a simple reed switch for the door and LED strip lighting with a 12V power brick. To save power, I don't want to just keep the power brick plugged in and control PWM to turn on and off the lights, so I'm using a relay (module for now, so the schematic doesn't show any supporting components) on the AC side. The microcontroller detecting the reed switch and controlling the PWM will run on 2-3V, mostly in sleep mode from the battery. The relay needs 5V so I need a boost converter to get it to turn on.Once on, the power brick will create 12V output and power the lights (cue fade-in PWM from the uC). And also a 5V linear regulator that will take over supplying the power for the relay and the uC. The battery and boost converter can be disconnected at this point, and the wall power will keep the circuit going without further battery drain until the uC detects the reed switch closing again, at which point it fades out the PWM and turns off the relay. When the 5V linear regulator output drops, the battery and boost converter are reconnected for the cycle to restart.Here's my schematic so far. I hope it's legible and looks ok, I'm also a newb with Fritzing. My basic questions are - 1) have I done anything stupid? and 2) does it look like it might work? I'm open to suggestions on the project generals but keep in mind I'm mostly trying to learn, so if I've made things overly complex it's just to try something out. I'm not trying to do this the best way.Thank you!
Schematic fo PIC16LF1938-I/SO - Page 1
Forum section: electronics / projects

author: ResR
author_rank: Regular Contributor
timestamp: September 29, 2013, 12:59:01 pm
content: Can anyone source me the schematic for PIC16LF1938-I/SO or any other smd MCU with on-board programming possibility. It's used for remake of the robot project using much compact and cheaper smd components. It is planned as wireless, with basic movement (left, right with solenoids, foward and backwards with rear wheel drive) and at least 8 lights on-off switching remotely from controller to device, also audio and video feed back from device to controller. Any suggestions for better MCU is also appreciated.

author: amyk
author_rank: Super Contributor
timestamp: September 29, 2013, 01:04:04 pm
content: Did you meandatasheet?

author: ResR
author_rank: Regular Contributor
timestamp: September 29, 2013, 04:06:30 pm
content: Something like that I was looking for, thanks. I have no idea why I missed that on Digikey. Oh another question: can I use radio 27MHz for digital data link between device and controller or is there any other frequencies for free use for this application?

author: mamalala
author_rank: Unknown
timestamp: September 29, 2013, 04:39:43 pm
content: Quote from: ResR on September 29, 2013, 04:06:30 pmYou need to check what frequencies are allowed to use for such a purpose. Normally the 11 meter band (27 MHz) is used for CB radio. For example, here in Germany only on a few channels in that band are allowed to do data transmissions.You will probably be better off to use some ready-made RF modules that work in one of the ISM bands (2.4GHz, 434MHz, 867MHz, 915MHz, etc.) that are available in your country.Check here for info about ISM bands:http://en.wikipedia.org/wiki/ISM_bandI often use the RF modules from HopeRF:http://www.hoperf.com/rf/module/Basically you just need an SPI connection to the module and write a bit of software, then you are good to go. These modules are pretty cheap as well.Greetings,Chris

author: ResR
author_rank: Regular Contributor
timestamp: October 10, 2013, 06:11:33 pm
content: Thanks for your help, Chris. It looks promising.OT: Although I managed to find MC6802P and a few 5V logic chips for free from scrap bin at my workplace and started to make a demo version based on that dip-40 chip, I'm little suspicious about it though, another board from that device had signs of overvoltage - 2 of 4 green led's were turned into conductors.Martin.
schematic for 60Hz notch filter (passive) for input to DMM - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: August 25, 2018, 10:03:52 pm
content: I thought to make a passive notch filter using the highest voltage components I can find to get rid of 60Hz for a ACDMM measurement.Any circuits?

author: ejeffrey
author_rank: Super Contributor
timestamp: August 26, 2018, 04:07:40 am
content: A twin-T notch filter is a pretty common passive notch filter. It's handy because it doesn't have any inductors, which tend to be impractical for low frequency, high impedance filters. The notch can be very deep, but the shoulders are quite broad so it isn't going to do it if you need to measure a signal at 55 Hz.
Schematic for Japanese 1975 SS91 Silver Receiver-Amplifier - Page 1
Forum section: electronics / projects

author: jonovid
author_rank: Super Contributor
timestamp: September 01, 2024, 03:13:31 am
content: seeking a schematic for a 49 year old Japanese receiver-amplifier. part of the SILVER rack system.I have two SS91 Silver receivers. one is working but not the other.using my second workstation as the other work bench is full of incomplete projects.the still working SS91 had a dead mummified mouse & spider removed. just how a mouse got inside the case is puzzling.repaired the dial cord stringing as the knob shaft had failed. so the aluminium clad, plastic front cover had to be removed.cannibalizing knob shaft parts from the no-working receiver. at the present time replacing dial lamp on the backlit signal strength meter.looking at the circuit board on the working receiver. I note that the 49 year old electrolytic capacitors may need replacement.but without a schematic this could be problematic if the receiver stops working when swopping out electrolytics.looking online for a 49 year old SS91 Silver circuit board schematic was disappointing. so the old but still good electrolytics remain in place.this receiver has both good selectivity & sensitivity on all modes MW FM & SW . this Japanese receiver had an FM band in 1975 .just how long the working receiver will continue to operate reliably is unknown.
Schematic for PSU-AC-62 wanted - Page 1
Forum section: electronics / projects

author: oz3qy
author_rank: Newbie
timestamp: December 25, 2022, 11:43:57 am
content: Hi allI’m looking for schematic and other possible information on a network switching power supply. Make and type number is EMERSON / DELTA ENERGYPSU-AC-62. It is also known as EricssonBML 161 174/1.
Schematic for switching an AC-220V motor with ON/OFF non-locking switch - Page 1
Forum section: electronics / projects

author: VSV_electron
author_rank: Regular Contributor
timestamp: October 20, 2022, 06:18:13 pm
content: Hello,Not long ago I bought a 2-button On-Off switch to control the ON-OFF state of a Taig micro-lathe. The description indicated it was a locking switch, that is either button was supposed to stay in its respective "down" state until the accompanying button was pressed. The power rating of the switch is 3A at 230V AC. The specs suggested that's a power switch.However, on receipt I found that the buttons are NON-locking type and this switch as a result is not a power switch but rather a power control switch that needs a separate device responsible for activating the motor and "locking" the ON/OFF state such as a magnetic contactor. I have a dilemma now: either to return this 2-button switch (and get a locking ON-OFF type) or to implement a simple schematic for the power ON/OFF state of the motor.Please advise what would be the most common and simplest way to implement such a schematic. You of course understand that using a magnetic contactor for a 250W 220V AC motor in the micro lathe is an overkill.NOTE: You may of course suggest me to use a simple toggle switch in place of a 2-button switch (many Taig owners use just that and are happy) but I wanted to make it work more like a serious lathe power ON/OFF switch which is always a 2-button type.Here is how the button looks (I bought in a different store, btw):https://aliexpress.com/item/883125434.html

author: inse
author_rank: Super Contributor
timestamp: October 20, 2022, 06:45:09 pm
content: You have three options: contactor, return, trash bin because you somehow need to latch the on-state.Above that, the latching switch type has a safety function not allowing the machine to restart after a power outage.Judge the risk of this happening by yourself.

author: themadhippy
author_rank: Super Contributor
timestamp: October 20, 2022, 07:21:17 pm
content: Quoteuse a 3 pole relay instead,2 poles for the power and the third for the self hold circuit
Schematic for this buck converter? - Page 1
Forum section: electronics / projects

author: Ray CI
author_rank: Contributor
timestamp: May 13, 2023, 05:52:54 pm
content: Hi Folks...Does anyone happen to know if the schematic is available for this very common buck converter available on Amazon, eBay and many other places? Yes, it's probably not terribly hard to reverse engineer but, I'm looking for the easy way out. FWIW, I've used these in a few projects and they're not bad at all if used within reason.Amazon:https://tinyurl.com/4xeybapneBay:https://tinyurl.com/2p94cb2jThanks...Ray

author: langwadt
author_rank: Super Contributor
timestamp: May 13, 2023, 08:36:48 pm
content: most likely straight from the datasheet example

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 13, 2023, 10:16:32 pm
content: The listed IC is the MP1584, the datasheet can be easily found. And sure the schematic is the bare minimum judging from the picture.https://www.monolithicpower.com/en/mp1584.htmlBe aware that the actual IC on the boards you'll get may be different. Happens very frequently.

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 14, 2023, 12:22:00 am
content: This seems to be it:HD picture attached.

author: Ray CI
author_rank: Contributor
timestamp: May 14, 2023, 12:24:52 am
content: Quote from: SiliconWizard on May 13, 2023, 10:16:32 pmQuote from: langwadt on May 13, 2023, 08:36:48 pmBoth of you are probably right.I looked at the datasheet some time ago but, didn't pay much attention to the reference design.FWIW: I found a particular batch that worked very well and bought 20 of them for about $18. I was thinking about doing some experimenting with them.ThanksRay

author: Ray CI
author_rank: Contributor
timestamp: May 14, 2023, 12:28:21 am
content: Thank you David!Yes, that sure looks like it!Ray

author: strawberry
author_rank: Super Contributor
timestamp: May 14, 2023, 03:08:58 pm
content: SS34 0.5V@3A ~1.5Wstatic lossMP1548 input ~1.3W static lossinductor ~1W@3A+switching lossreally hot
Schematic from reverse engineering of two inductive different proximity sensors - Page 1
Forum section: electronics / projects

author: taser8612
author_rank: Newbie
timestamp: October 18, 2020, 10:51:00 pm
content: I bought a couple inductive proximity sensors from two different over-seas manufacturers and set about trying to reverse engineer them. After cutting away the casings and boiling the resin the tiny boards were encapsulated in, I did my best to identify the components and their connections. This schematic for the two different boards is the result.I am but a hacker (no formal education or training in electronics), but research tells me these sensors include an oscillator, demodulator and output signal processor. I think I recognize a Hartley oscillator but I am unable to decipher the rest.I tested them both before tearing them apart and they both performed as advertised. Sensor A was happy with just 5 volts from an Arduino, but sensor B required at least 6 volts to function.I'm hoping those more knowledgeable can look at the schematic and determine (1) if the design would work and (2) how they can be so different and accomplish the same thing.
schematic needed - Page 1
Forum section: electronics / projects

author: p.larner
author_rank: Frequent Contributor
timestamp: October 23, 2023, 01:04:29 pm
content: i want to build an oscillator to drive a small transformer that will output ac,the output of the transformer only needs to be a few ma at say 24v max,powered from an 18650,any ideas?.its to build a small octopuss component tester to work with a handheld scope in xy mode,the idea is basicaly have a small portable huntron tracker.

author: Terry Bites
author_rank: Super Contributor
timestamp: October 23, 2023, 07:50:50 pm
content: 4000 series cmos will work happily down to 3V.Paralleling gates gives plenty of output drive for your mosfets or transistors.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: October 23, 2023, 08:00:32 pm
content: Hi Terry,sorry to contradict you, but a square-wave will not do for a component-tester.Sine- or triangle-wave is needed (imho).Best regards

author: p.larner
author_rank: Frequent Contributor
timestamp: October 23, 2023, 09:40:46 pm
content: thats what i thought,a square wave will smack a transistor or diode junction on or off,not turn it on in a linear manor to display properly on a iv tester?,is that right?.

author: Kim Christensen
author_rank: Super Contributor
timestamp: October 23, 2023, 10:13:09 pm
content: I assume the amplitude and frequency isn't super critical:You could LPF a 50/60Hz square-wave or triangle-wave (to turn it into a pseudo sinewave) and feed that into an audio amplifier IC to drive a small step up transformer. (Low voltage mains transformer in reverse)Or feed the AF amp from a phase shift oscillator running at 50/60Hz.
Schematic of a chinese amp board from ebay - Page 1
Forum section: electronics / projects

author: Michaelaudio
author_rank: Regular Contributor
timestamp: September 29, 2020, 06:05:55 pm
content: Does anyone know where I can get a schematic of this board? (Reverse engeniering really sucks on this one ) There is no Brand or anything on it sadly, u can get this board from ebay and Ali express.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 29, 2020, 07:08:58 pm
content: youll have to translate the chinees characters ?? msut be a class H amplifier of some sorttry to unscrew the heatsinks to see the part numbers

author: Michaelaudio
author_rank: Regular Contributor
timestamp: September 29, 2020, 07:34:45 pm
content: Its a tpa3116 amp board, the Chinese Letters are translated in english just under them.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 29, 2020, 11:29:39 pm
content: knowing the part number, search for the datasheet and application notes, you can make the schematic yourself ??

author: ebclr
author_rank: Super Contributor
timestamp: September 30, 2020, 02:21:23 am
content: It's not a schematic but have a lot off detailshttps://item.taobao.com/item.htm?spm=a230r.1.14.72.4d67388cZpsyU1&id=521337200949&ns=1&abbucket=9#detailUse google translator
Schematic Review of Clock Project - Page 1
Forum section: electronics / projects

author: cougar618
author_rank: Newbie
timestamp: June 20, 2020, 09:04:13 pm
content: Hi all!I'm new here, and I believe this is the right place. I have a design I'm working on, and was hoping someone could give the power and USB portion of it a look over.The schematic PDF is here:https://drive.google.com/file/d/1Uuv5jio_vhPbxPwsWwzzxBKSSQ_cVjdH/view?usp=sharingSynopsis:I'm trying to power a 132 LED ( of which, 60 are RGB) clock via the Type-C port. I want to take advantage of the USB-PD spec, which is why I have the STUSB4500 chip. The plan is for normal operations it gets 15-20V, passes it to a DC/DC converter, and then get 5V over 2 seperate rails.There's also the microC logic, which sits between two bidirectional power switches. The idea here is if the board is plugged into the PC, I would be able to program the microcontroller.I don't have much experience with BPS's, DC/DC converters or the type-c, actually. I was hoping you guys could help me out and look over the power portion of it. The schematic is 11 pages (8.5x11), but half of those are just LED's.I'm sure there's some really dumb dumb small brain mistakes on here, hoping to learn at the very least.Thanks!
Schematic Review Request: USB HID Control Device - Page 1
Forum section: electronics / projects

author: copperrat
author_rank: Newbie
timestamp: February 21, 2024, 07:59:52 pm
content: This is the schematic for a USB HID device that I am going to use to control software I am working on. I plan on putting a WS2812B LED string on this (about 10-15 LEDs). I have designed some simple PCBs before but I'm primarily a FW/SW engineer, so I don't dip my feet into this as often as I like.I checked this over a few times and I think I got all the obvious issues, but I'd like to see if anyone has some feedback or sees any problems.A couple questions:Do I really need this many TVS diodes? I put them anywhere I will be touching frequently because of ESD events on the recommendation of a HW engineer I know.For the 5V rail for the WS2812B LEDs, will I need extra capacitors? I have two 22uF caps there, but will they interfere with the USB VBUS line since they are being powered from it? The USB spec says the line should have no greater than 10uF of capacitance.Note: the header with PWM and MOSI is there because I am not sure if I am going to use the SPI MOSI for the LEDs, I want to experiment with both.I broke out some audio lines as I may try to route USB audio through it in the future (if I get adventurous enough).
Schematic standard for fixed logic input? - Page 1
Forum section: electronics / projects

author: beaker353
author_rank: Unknown
timestamp: September 20, 2014, 06:01:46 am
content: Does anyone know if there is an official standard to designate a fixed logic level on a digital logic gate/block in a schematic? Think your standard JK flip-flop where the J & K inputs are often tied high for the flip-fop to act as a frequency divider. In a schematic you can tie the J & K inputs to Vcc, but being that it's actually a logic input and not a power input, I feel that just indicating the logic level is more straightforward and makes for a cleaner and better looking schematic. Google has proven to of little help with the only thing vaguely helpful was from a IEEE standard 91-1987 document describing how to designate a fixed OUTPUT. [See attached picture] I'm guessing I could just do the same concept for an input, but I'm curious to hear if there is a/some accepted standards that are more "tribal knowledge" in the electrical engineering world as hard documentation seems to be scarce... Thanks!-EM

author: tautech
author_rank: Super Contributor
timestamp: September 20, 2014, 07:14:53 am
content: QuoteDepending on the schematic editor that you use, assign a VCC power port label to the VCC supply AND to the GND. Then hide the IC's power pins(VCC & GND). They should connect invisibly.Then any pin that requires to be tied H or L, just attach the appropriate power port label to it.That will keep schematics tidy.At a glance it is obvious which pins are tied H or L.

author: beaker353
author_rank: Unknown
timestamp: September 20, 2014, 07:54:18 am
content: Tautech, what you describe is what I currently do. However, with some higher pin devices and complicated sets of some pins tied high and some low, it gets messy and not easy to follow in a hurry. In textbooks they often just have a 1 or a 0 next to an input to indicate a fixed value. Would make it easier to decipher a counter MOD number or a set of slew of device parameters (my current messy schematic). I can the use the textbook style indication, but I figured there might be something more elegant that is commonly used.- EMSent from my iPhone using Tapatalk