hybridfree/eevblog-posts huggingface dataset:
3PST switches - Page 1
Forum section: electronics / projects

author: MONODA
author_rank: Contributor
timestamp: June 09, 2012, 03:55:36 pm
content: So I've been working on a development board recently which includes a PCB prototyping area and another area with a potentiometer connected to the micros ADC and pushbuttons connected to the Digital input. Obviously, I dont ALWAYS want these to be connected so I've been trying to come up with a way to enable or disable these features whenever I would like but am having trouble figuring out how I could do that. My first idea was to use switches with an abnormally large number of poles (3 and up) with a single throw or using DIP switches but I really dont like either of these solutions. I feel like Im missing something really simple. Any ideas?Thanks!

author: 8086
author_rank: Super Contributor
timestamp: June 09, 2012, 05:00:25 pm
content: How often will you be switching them in and out? If it's not too often, you could use solder bridges. Either apply or remove solder depending on which you want connected.

author: TerminalJack505
author_rank: Super Contributor
timestamp: June 09, 2012, 05:15:12 pm
content: One idea is to use 0.1" male headers on the board for the MCU pins and the on-board components (switches, pots, LEDs, etc.) and then use female-to-female jumpers (for example) to connect them. This will allow any MCU pin to connect to any component.

author: MONODA
author_rank: Contributor
timestamp: June 09, 2012, 08:08:37 pm
content: Awesome, I really like the jumper idea. Ill give it a try
3S 20A BMS board resistance  - Page 1
Forum section: electronics / projects

author: grmsyd
author_rank: Newbie
timestamp: July 13, 2024, 12:35:19 pm
content: I notice a 100k ohm difference between the negative input and 0V output,However when connecting an output to a 16850B battery it shows 0 ohm difference,Is this normal?

author: Phil1977
author_rank: Frequent Contributor
timestamp: July 15, 2024, 09:39:29 am
content: It´s the purpose of that board to behave that way.It´s more or less a MOSFET-switch that switches the cells from the load or charger if anything is out of the SOA-windows.If no cell is detected, you are outside of the SOA-voltage and so the switch is open --> high resistanceIf healthy cells are connected, the switch is closed --> low resistanceThe FET in the standard BMS-boards usually is on the low-side, so it´s to be expected that you measure these resistances between battery-ground and output-ground.The only strange seems to me that you say the connection of *one* 18650-cell switches on the output. Usually for a 3S-system all three voltage levels must be present.
3s battery charger - Page 1
Forum section: electronics / projects

author: artag
author_rank: Super Contributor
timestamp: April 09, 2020, 10:58:30 am
content: I've used the TP4056 boards for charging and protecting 3.7V lipo cells but am looking for something similar for a 3S pack.So far I've found BMS boards which balance the pack and can be used with a constant voltage / maximum current supply for charging. However this combination doesn't do charge termination - it only drops to the current taken by the pack at max charge voltage and won't detect faults.Is there an off-the shelf solution (ideally using cheap ebay components) to handle the whole charge and protection for a built-in battery pack ? I don't want to remove the pack so I can't use a standalone packaged charger like those used for model aircraft.

author: IDEngineer
author_rank: Super Contributor
timestamp: April 09, 2020, 04:42:45 pm
content: Quote from: artag on April 09, 2020, 10:58:30 amI think you're close to your own solution here. There are very small "standalone packaged chargers" for 3S packs available on eBay... how about removing the PCB from its enclosure and putting that into your device? It's unlikely you'll be able to one-off anything smaller or cheaper. Just a thought.

author: artag
author_rank: Super Contributor
timestamp: April 10, 2020, 08:36:25 pm
content: That's a option, I guess. There do seem to be some that accept 12VDC in, which I'd want.Unfortunately they are only chargers : they don't implement the other functions of a battery pack, notably cutoff when at low voltage. So I'd have to add that circuit.
3S charger - Page 1
Forum section: electronics / projects

author: lucibel
author_rank: Newbie
timestamp: November 26, 2021, 04:01:04 pm
content: Hi, guys..newbie here..i just tried to design a 3S charger but it seems like my design is not working properly..it charges one battery fine but kinda disregards the other two..i measured the voltages of the batteries but they are unusual..

author: bugnate
author_rank: Regular Contributor
timestamp: November 26, 2021, 09:45:29 pm
content: It is not going to work. You cannot float GND_1 and GND_2 like that without an isolated power supply, which the AP62201 ain't. You say the cell voltages are "unusual" which I take to mean you are likely damaging them and need to be very careful to avoid a fire etc.
3s2p Lithium Battery and Charger - Page 1
Forum section: electronics / projects

author: cpfeiffer55
author_rank: Newbie
timestamp: July 25, 2024, 12:59:25 am
content: I have a device that will be using a 3s2p lithium battery pack. If this was a standard device that used house power I would be set however this device might not have local house power nearby hence the battery pack. I found a UBBL25-FL pack and a UCH0038 charger from Ultralife. I am not familiar with wiring this power to my device. The battery pack will be hardwired in the enclosure and I plan to have a barrel connection panel mounted to plug in the charger when the battery monitor shows low power. My question is can I have the charger connect to the battery pack while it is still powering my device or do I need to break the load circuit from the battery when charging? I understand that might increase charging time if even possible but I don't even know if it is standard practice. Thanks in advance.
3V3 device control 5V ESC? - Page 1
Forum section: electronics / projects

author: mrburnzie
author_rank: Regular Contributor
timestamp: January 17, 2020, 10:39:47 pm
content: I have a dsPIC33 which produces a 3V3 PWM signal (50hz). It is ment for an ESC (cheap chinease one) 30A, but it doesn't react on 3.3V signal.I have tried with an arduino mega (5V I/O) and everything works perfectly. I have compared the signal between the arduino and the dsPIC, the only difference is the voltage. On arduino works, dsPIC doesn't.I got a level shifter (https://i.ebayimg.com/images/g/HtIAAOSwilVbpMWY/s-l640.jpg).The problem is when I don't have the ESC powered, I get a 5V pwm output, but when I power the esc (as I must because they have to boot up on the max pwm duty cycle), the voltage drops back to 3.3V.I have everything wired correctly, GND is all connected. Is this some impedance problem?

author: mrburnzie
author_rank: Regular Contributor
timestamp: January 17, 2020, 10:46:10 pm
content: Would something like this solve the issue?https://assets.nexperia.com/documents/data-sheet/74HC_HCT245.pdf

author: ebastler
author_rank: Super Contributor
timestamp: January 18, 2020, 01:04:51 pm
content: Quote from: mrburnzie on January 17, 2020, 10:39:47 pmI can clearly see from the link you provided that your level shifter PCB is red. That obviously can't work.Seriously though, a link to a technical description of the level shifter, and information on the chip it uses, would be much more useful than a small photo of several boards. Also, pardon my ignorance, what is an "ESC" to you? It's one of the more popular acronyms...

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2020, 11:21:47 pm
content: I Googled for HtIAAOSwilVbpMWY and got this ebay hit.https://www.ebay.ie/itm/5Sets-4-Channel-Bi-Directional-Logic-Level-Shifter-Converter3-3V-5V-ForArduMA-PN/133166967704?hash=item1f015eab98:g:HtIAAOSwilVbpMWYIt appears to be a simple MOSFET level shifter, like the one Sparkfun sell.https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/allThe only thing I can think of is the output impedance of the shifter is 10k, when the output is high and it's being loaded, pulling the voltage down.
4-20 mA signal to IFM DP2200 - Page 1
Forum section: electronics / projects

author: idir93
author_rank: Newbie
timestamp: August 29, 2024, 02:50:51 pm
content: Hello,I have an Oxygen sensor that outputs a 4 -20 mA signal. I also have an IFM DP2200 to receive the signal on the PLC side.I am having trouble to understand how to wire them together.The DP2200 is supposed to supply power (24 vdc) to the sensor. However, the sensor already receives its power from a different power supply (12vdc).See below diagrams.Regards,
4-20mA current loop input protection - Page 1
Forum section: electronics / projects

author: nametaken
author_rank: Newbie
timestamp: November 25, 2016, 11:37:52 pm
content: hello!I'm working on a device that would work with a industrial 4-20mA sensor.I figured, to not overcomplicate things, the simplest solution would be the best.So a 220R resistor will give a nice 0-4.4V output for an ADC with room left for 2mA error. Sounds simple enough.But then, came the real world and Murphy's law "Anything that can possibly go wrong, does."What if some one shorts it to the 24V supply line? The resistor has to dissipate 2.6W! I don't have space for a resistor that big.-First solution would be to get a MAX14626 it's a current loop protector. I'm sure it would work, but it's 1usd/pc, but can we go cheaper?-Second solution would be a zener diode, let's say 4,7V and a PTC fuse. When voltage rises above the zener voltage it starts to conduct and trips the fuse.It sounds a little "brute force" to me. In practice it seems that Zener diodes don't start to conduct at their rated voltage, but slowly ramp up. Also fuses rated below 100mA are not very common.I have a general "meh" feeling about this one for some reason.-Third seems the best so far. Analog comparator and a mosfet. Pretty much a "if U>4.4V then switch of the mosfet". Seems to work ok on a breadboard. I have to solder it up and measure everything properly.-Fourth, TI has a IC current loop receiver(RCV420) and in its datasheet there's a "overload protection". It consists of an solid state relay, 555 timer and a double op-amp. I rather go with the MAX14626 than this.I'd appreciate any input on this, comments, tips, critique, whatever.

author: Zero999
author_rank: Super Contributor
timestamp: November 26, 2016, 12:39:04 am
content: What about a crowbar? A thyristor with the zener connected to its gate so it short circuits the supply, tripping the polyfuse, when the safe voltage is exceeded.

author: langwadt
author_rank: Super Contributor
timestamp: November 26, 2016, 01:21:32 am
content: prg18bb470mb1rb and series resistor diode clamp on adc input

author: David Hess
author_rank: Super Contributor
timestamp: November 26, 2016, 07:12:30 am
content: Why not add a two terminal constant current source (or something more sophisticated) in series with a supply? Then if the output is shorted, the current will be limited to some convenient level like 30mA or whatever you select.

author: Seekonk
author_rank: Super Contributor
timestamp: November 26, 2016, 02:50:28 pm
content: A PTC will protect the resistor. Add a 47K resistor in series with he A/D input. That will limit the input current to a safe level the micros internal diode can handle. Put a .1uF at the input pin to ground. This will provide a low source for the converter.
4-20mA magnetic sensor - Page 1
Forum section: electronics / projects

author: tszaboo
author_rank: Super Contributor
timestamp: June 07, 2022, 03:57:34 pm
content: Does this product exists? I've been trying to find one for hours now, and I think I'm ready to give up.I'm searching for a magnetic sensor, magnet-o-meter, gauss sensor, magnetic field sensor or whatever you want to call it (seriously, we should decide on a name for it) which would be with a 4-20mA output. Or USB. Its for production testing. We make a small magnet-in a box that we include with a product, and the plan is to include some quality control with it. The magnetic strength matters for the product, so lets just buy a meter for it. The operator places the magnet in the jig, presses a button on the PC, a measurement is made, saved, green light/red light. But this sensor doesn't exist. I went through the datasheet of probably a hundred sensor now, which only have a reed switch or NPN or PNP output. Analog output - doesn't exit. There are plenty of ICs, but I just want one of the thing without me making a PCB for it. I need help, how is this thing called?

author: langwadt
author_rank: Super Contributor
timestamp: June 07, 2022, 04:27:30 pm
content: gauss or tesla meterhttps://www.wuntronic.de/en/usb-gauss-meter-tesla-meter-with-analog-output.html

author: GeoRock
author_rank: Newbie
timestamp: June 13, 2022, 08:27:57 pm
content: As langwadt said, it is an gaussmeter that you are looking for (generally different names are used depending on the range of fields measured). There are plenty to be found, but good ones with PC interface tend not to be too cheap, also, you may need to write custom software.Some examples can be found on RS:https://uk.rs-online.com/web/c/test-measurement/environmental-test-measurement/gaussmeters/Since you are measuring a static field (I assume a permanent magnet), you just need a DC meter. The sensitivity depends on the moment of the magnet and the distance between the magnetic and the probe. Depending on the magnet and the setup, I would guess you would be expecting to measure fields on the order of ~1mT up to a few 10's of mT (~1-1000 G).Hope this is helpful

author: TimFox
author_rank: Super Contributor
timestamp: June 13, 2022, 09:07:25 pm
content: For your application, the gaussmeter will probably use a Hall-effect sensor, which is inherently analog.For stable readings of DC fields, the Hall sensor may be excited by AC, with an appropriate AC-DC converter (hopefully, a synchronous detector) after the amplifier for the Hall voltage.You might have better luck searching for "Hall-effect sensor" to get a component or subsystem level device.(Be careful with your fixturing, to ensure that the plane of the sensor is perpendicular to the field internal to your magnet being tested.)Back in the day, I used laboratory-grade Hall-effect gaussmeters from F W Bell.https://fwbell.com/
4 - 20mA Simulator - Page 1
Forum section: electronics / projects

author: StreetRooster
author_rank: Newbie
timestamp: March 22, 2019, 10:33:46 am
content: Hi AllFrom time to time i need to apply a 4 - 20mA signal to a circuit replacing the 300 Bar. Pressure Xducer for fault finding reasons.where can i got a kit or diagram for a current source i can build myself.

author: AndersJ
author_rank: Frequent Contributor
timestamp: March 22, 2019, 11:40:49 am
content: What have you tried?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 22, 2019, 11:44:12 am
content: https://www.instructables.com/id/Simple-4-20mA-Calibrator/?

author: soldar
author_rank: Super Contributor
timestamp: March 22, 2019, 04:32:45 pm
content: Wait a minute. I thought the controller supplies the power and the transducer is powered by the controller and varies the loop current between 4 and 20 mA. So what do you want to do? A transducer simulator which will vary the loop current so you can test a controller? Or a controller simulator which will provide power to test transducers?Or is it that you are trying to simulate transducers which have their own power supply and power is not supplied by the controller?Or am I not understanding the question?

author: tszaboo
author_rank: Super Contributor
timestamp: March 22, 2019, 04:43:10 pm
content: Or NSI50010YT1GDoesnt get easier than this.

author: soldar
author_rank: Super Contributor
timestamp: March 22, 2019, 05:50:28 pm
content: Also, if you are just trying to test the controller, note that almost always the current just goes through a 250 ohm resistor and the controller is reading 1 ~ 5 volts so if you are right at the controller and testing it then you can just connect a 1 to 5 volt power supply.

author: StreetRooster
author_rank: Newbie
timestamp: March 25, 2019, 10:27:02 am
content: Thank you for your reply.In my case all the transducers get there supply from the system 12V / 24V.They then return a proportional 4-20mA loop current back to the controller. the controller then either processes the signal or displays the value of the processed (4-20mA) signal value.The signals are reference to Length, Angle, pressure, temperature rotational speed, etc.When fault finding in the field, it will make it so much easier to be able to plug in my 4-20mA "simulator" and thereby eliminate {pin point the cause of the fault.)Transducer, wiring or the controller itself.

author: soldar
author_rank: Super Contributor
timestamp: March 25, 2019, 11:16:13 am
content: And you could just use a resistor, fixed or variable.And even put a meter in series if you want to know the exact current flowing.
4.3 inch LCD, 480X272 pixels with Capacitive touch screen  - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 16, 2017, 08:41:42 am
content: Hi,I have ordered 10 samples of the new beast in town MIMXRT1052DVL6A, I wanted to know if you happen to know a good and reliable china made 4.3 inch LCD with the Capacitive touch screen, I wanted it to be in good quality and have reasonable prices, since the beast cost is so damn good, if the Panel and the touch passed our test, I need them to be manufactured at least 3 years cause I will order in the range of 10K to 20K each time after that.Any part number or hint is highly appreciated, the capacitive touch is a must

author: Rerouter
author_rank: Super Contributor
timestamp: December 16, 2017, 09:03:48 am
content: I've used them aswell, the postage is a bit on the high side, but I've used a number of there TFT's in products, and so far haven't had any issues.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 16, 2017, 10:30:00 am
content: Thanks and big thums up, do you suggest any other model form them, since I need the capactive touch option and My MCU is i.MX RT seriesAlso since the RT series have built in LCD controller there would be no need for any controller inside the panel.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 17, 2017, 06:50:22 am
content: Thanks
4 bit magnitude comparator vision system + DTMF Quadcop idea - Page 1
Forum section: electronics / projects

author: rickey1990
author_rank: Regular Contributor
timestamp: May 30, 2015, 08:18:59 pm
content: So its a Sunday, just spent some money on a few new components and have been looking through my component draws, where i came across a 4 bit magnitude comparator and fort what can i do with it. I wanted a better vision system for a robot design called head walker, so iv been experimenting with things, The robot is a Light following walker, Head turns to the brightest source of light then the body follows. also added a sharp ir sensor for reversing. Rough design attached.Using these for ease of use £0.50I have also been working on my drone project, i decided to put a arduino between the receiver and motors, so that i could also use the arduino as a on board computer for proximity sensors ect. it was ok But it got me thinking about using a 16 channel DTMF module with a old phone which would be on board. then id ring the phone and control the drone like that. I also purchased a cheap quadcopter board with firm loader so i could send the DTMF signals into the flight controller. the main issue with this design will be with the control surfaces, distinguishing between light and large stick movements. But iv looked on DTMF module and there is a toggle,latch and momentary. so il have to play around with it. But the main advantage is signal, youv got the mobile phone towers doing all the hard work, you can send video by 3/4g with the camera on your phone,so range now turns into a battery problem.
4 conductor shielded cable- Crosstalk? - Page 1
Forum section: electronics / projects

author: FenderBender
author_rank: Super Contributor
timestamp: February 10, 2013, 02:38:00 pm
content: Hello everyone,One final question about my amplifier that I brought up in a separate thread. I know this isn't an audio forum but this isn't audio specific, I don't think.If I have two separate audio signals. (Left and Right) and I put them in the same cable, will there be problems with interference or crosstalk with each other?Here's the cable I'm using:http://www.mogamicable.com/category/bulk/microphone/quad/Mogami W2534Thank you.

author: Unknown
author_rank: Unknown
timestamp: February 10, 2013, 03:12:23 pm
content: Short answer: YesLong answer:On the link you gave there is a schematic at the bottom. Draw this in LTSpice and use the values from the table above to see exactly how much effect is there. Chances are that it doesn't make all that much difference.

author: Marco
author_rank: Super Contributor
timestamp: February 10, 2013, 03:58:12 pm
content: The cable is pretty well specified, lets just do some approximate math ... for a meter you have around 0.2 Ohm path resistance and 100 pF between pairs I think, at 20 kHz the impedance from the capacitance is around 100 kOhm so the attenuation between pairs will be around 500000. Theoretically with 24 bit sampling this gives cross talk ... practically for audio it won't, it's quite a few dBs beyond the dynamic range of 16 bit sampling.

author: CarlG
author_rank: Regular Contributor
timestamp: February 10, 2013, 06:18:15 pm
content: Assuming that the driver impedance << input impedance, the crosstalk depends on the driver impedance in relation to the impedance (capacitive coupling) between the leads. IMO, the cable's lead resistance is not relevant in this case.

author: FenderBender
author_rank: Super Contributor
timestamp: February 10, 2013, 06:36:02 pm
content: Alright. Thanks. I guess I'll try to keep them separate, though I agree, the effect doesn't seem like it would be terribly big.
4 controller USB3 card for M.2 slot - Page 1
Forum section: electronics / projects

author: blazini36
author_rank: Regular Contributor
timestamp: May 10, 2023, 01:02:49 pm
content: This is a very niche PCB. It was meant to work with a small X86 SBC, the Odroid H2. That was discontinued but they brought out the H3 in the same form factor a while later. The purpose of this thing is because I do some stuff with machine vision cameras and at the time I was using USB3 cameras. If you've ever used high resolution USB3 cameras you know when you add a 2nd one to the same USB3 controller there are major issues with bandwidth. I have a tight form factor I try to maintain and needed something like this but the challenge is that the H2/3 has only an M.2 slot, not a PCIE slot.Odroid makes a netcard that uses 4, 2.5gbe controllers and they have a special bios that splits the m.2 x4 PCIE lanes into 4 x1 lanes so no PLX chip is necessary. I started this thing, then the great chip shortage happened and I couldn't get ahold of USB3 controllers which is difficult anyway since not many are available directly to consumers so the initial design used an obsolete TI chip which was a bad idea. Between the H2 being discontinued and chip problems I dropped and picked this thing up like 4 times. Now Renasis chips are readily available so this last design uses the common Renasis controller.At some point I ran a prototype which wound up not being worthy of use because an M.2 slot uses a 0.8mm PCB. I used type A connectors and it was obvious the thing wasn't gonna handle 4 USB cables plugged into it. I reworked it into USB3 headers with a mechanical stiffener since that actually works better with my required form factor anyway (meant to sit in an electrical enclosure). I got sidetracked and didn't finish routing it but it looks like I finished the schematic and routing is only a little work left.I'm pretty much a novice when it comes to 4-layer PCBs and PCIE and USB3 so rather than wrapping it up and shooting out another prototype I figured I'd share it and see if anyone has any suggestions. I don't think I've touched it in like 6 months and I just uploaded it to git as it was. This is in KiCAD BTW. Any suggestions are appreciated.https://github.com/ShadeTechnik/ST_H2_USB3-4
4-digit 7-segment LED display: not a red light area - Page 1
Forum section: electronics / projects

author: PerranOak
author_rank: Frequent Contributor
timestamp: November 10, 2021, 05:39:23 pm
content: I'm looking for a 4-digit, 7-segment LED display that is green or yellow or, well, not red.I don't want it mounted on a PCB and I don't want the ones with a ":" between the digits, like for a clock.The trouble is that when I find one, often the picture does not match the description - suspicious.Is there a specific name or type I can search for that will yield the proper results?Cheers.

author: edavid
author_rank: Super Contributor
timestamp: November 10, 2021, 05:57:05 pm
content: They are easy to find on AliExpress.Here is a seller I have bought from with no issues:https://chelead.aliexpress.com/store/group/4-bit-digital/121968_507041080.html
4 Digit 7 Segment Serial Display - Page 1
Forum section: electronics / projects

author: buffalo_den
author_rank: Newbie
timestamp: February 13, 2019, 10:20:12 pm
content: Hi Guys,I have a 16 character data stream coming into the Arduino from a device through serial, I am trying to display 4 of the characters (11,12,13,14) on a 4 Digit 7 Segment Display.Example 1 16 Character data stream - l 0 ' ' 5 0 ' ' l 1 H O R N ' 'Example 2 16 Character data stream - l 0 ' ' 7 0 ' ' l 1 1 5 1 1 ' '(so what I would like to display on the 4 digit 7 segment display is (HORN)(so what I would like to display on the 4 digit 7 segment display is (1511)Im not to sure how to display the characters in their correct form (Eg. 1 = 1 Instead of 49 which I believe is the dec value) also i'm not sure how I would go about extracting just the 4 digits out of the 16 digit string.Would anyone be able to help me with this?

author: TomS_
author_rank: Frequent Contributor
timestamp: February 14, 2019, 01:59:38 pm
content: Quote from: buffalo_den on February 13, 2019, 10:20:12 pmIf the characters you want to display are always in the same position, you could buffer all received characters in RAM and then look at the memory locations corresponding to the positions in the string you want. You would need to know how to determine when one string has finished being transmitted so that you can reset the buffer pointer to position zero.If the characters you want are always at the end of a string, you could cycle all characters through a 4 position buffer such that at the end of receiving a string your buffer contains the 4 characters you want. Again you need to know how to determine when a string is finished so you can then process the 4 characters.Font wise, you can come up with anything you want and drive your display(s) via GPIOs, shift registers, whatever you need to produce the output you need. 7 segment displays need a bit of creativity, or you could look at using 14/16 segment displays instead.
4 inch TFT display  - Page 1
Forum section: electronics / projects

author: Alex QW
author_rank: Contributor
timestamp: January 18, 2024, 07:16:33 am
content: Hi guys,I am looking for a 4-inch TFT display with a touch controller and it is an SPI interface (8bits) most importantly it must be supported by the LVGL lib as I needed to use this display interface my esp32-s3 via SPI (8BITS).Display solder with an esp32 controller is not preferred due to I need my own PCB design in the future.Do you guys have any recommendations?

author: globoy
author_rank: Frequent Contributor
timestamp: January 18, 2024, 03:30:07 pm
content: Look at buydisplay.com (https://www.buydisplay.com/tft-display/tft-display-panel?diagonal_size=291)There's another often-used distributor too but I'm sorry the name escapes me at the moment.
4 layer board stackup copper thickness - Page 1
Forum section: electronics / projects

author: michaelym
author_rank: Regular Contributor
timestamp: June 18, 2014, 06:44:38 am
content: I saw in various places two versions1)1oz0.5oz0.5oz1oz2)0.5oz1oz1oz0.5zWhy would I choose one over the other? What is more common?Assuming the inner layers are PWR and GND should that affect the decision?Thanks

author: richard.cs
author_rank: Super Contributor
timestamp: June 18, 2014, 09:40:28 am
content: More common is to use:0.5oz1oz1oz0.5zwhen the board is intially etched and then after plating (for the vias) copper has also been deposited on the outer layers giving a final:1oz1oz1oz1oz

author: PointyOintment
author_rank: Frequent Contributor
timestamp: June 19, 2014, 12:25:33 am
content: If you have high-current traces on the inner layers you may want them to be thicker for better heat dissipation/less heat production, because they're not exposed to the air.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 19, 2014, 02:11:06 am
content: Hmm, I often see heavier copper preferred on the outer layers. Probably because it's easier to plate to final thickness there, whereas there may be concerns over stiffness or warping or via construction, or, who knows what.It's usually possible to get any combination of thicknesses I think, of course the design rules are more relaxed for thicker copper (6/6 rules are pushing it for 2oz on any layer, AFAIK?).Tim

author: poorchava
author_rank: Super Contributor
timestamp: June 20, 2014, 06:20:09 am
content: I remember hearing a PCB company telling me once, that the general rule of thumb in the industry is around 3-4mils/1oz, and it's strongly dependant on chemicals being used.While it's not that hard to make thick copper on the inner planes, the highest current traces are mostly on top and bottom to improve power dissipation.
4 Layer High Voltage Layout Review KiCAD - Page 1
Forum section: electronics / projects

author: Arsh ahmad
author_rank: Regular Contributor
timestamp: October 28, 2024, 07:44:32 pm
content: Hi All,I am working on 4 Layer Board Having some High Voltage Sections(125 Volts), and a bunch of other stuff like DAC, MCU. Would love to have some opinions, corrections, suggestions for the layout.Some routing and Ground Connections are still in progress, but most routing is done.One on the Top LEFT is HV Switching Type Boost Convertor and Centre one is an OPAMP whose output can go up to 100V which is connected to SMAThanks in Advance.
4 pin (or 3 pin) industrial sensor connector - Page 1
Forum section: electronics / projects

author: atwoz
author_rank: Regular Contributor
timestamp: August 21, 2013, 02:30:49 pm
content: Hello Everyone,Can anyone recommend a 4 pin (3 pin could also work) sensor connector? I need the male and female parts. The female connector will be attached to a case. If some sensors goes bad, the idea is to replace it easily. The case will suffer some very light vibration and shock 24/7 during several years.Thanks!

author: tszaboo
author_rank: Super Contributor
timestamp: September 01, 2013, 09:08:27 am
content: M12 or M8 connectors are considered industry standard for sensors. They are extremely sturdy, with locking, one of the best connection system you can use.
4 pin round connector for PSU output? - Page 1
Forum section: electronics / projects

author: ElectronSurf
author_rank: Regular Contributor
timestamp: April 24, 2020, 08:27:19 am
content: I was thinking instead of having four female banana plugs on the panel (two positive and negative, two for remote sensing), I use one of this 4 pin round connectors with USB or Ethernet cable since current is just 1A. and just two alligator clips.Can anyone please suggest better alternative 4 pin panel mount connector and/or proper cable with 4 wire?
4 Pole 5 Way Rotary Switch Selector headache - Page 1
Forum section: electronics / projects

author: Pete2103
author_rank: Newbie
timestamp: April 29, 2018, 07:07:21 am
content: HiI never thought it could be so frustrating to try and find pinouts on a 4 pole 5-way rotary switch. I have searched all over Google, came across several which look simple enough but cannot find anything which is like the one I have typicaltried with multimeter Coffee break & more multimeter, just when I thought it was correct it turned out it wasn’tHas anyone came across this type of switch, it’s very small, the solder lugs do not make any sense to me.ThanksPete

author: Ian.M
author_rank: Super Contributor
timestamp: April 29, 2018, 07:54:57 am
content: Pinouts for pre-Millenium parts are fairly rare and difficult to find on the web except for popular semiconductors where someone's scanned the paper datasheet. Without a make and exact part number you are usually S.O.L. Wafer switches are especially problematic, as there were various brands of rotary make-a-switch kit, some of which were customisable right down to loading individual bare wafers with contacts of different angular lengths. You can still buy switch frames with adjustable stops, and different types of individual wafer for them (all proprietary so not interchangeable accross brands and ranges), but nowadays the wafers come pre-assembled with a captive rotor.Better photos would help - in focus and properly lit so they aren't so grainy. Four with the pillars holding the switch body level, (use bluetack) at a slight oblique angle tilted to the front and to the back looking down into the contact side of each wafer as far as the center - take a pair from the top then flip it for the other pair, and one square on to the back wafer.Worst case you can always undo the two pillar nuts at the back and slide off the wafers and spacers one by one, photographing each wafer, and stacking the spacers and any washers on two stiff wires in the order they came off in to aid reassembly. It looks fairly old, so that's also a good opportunity to clean each solder tag so they take solder more readily.

author: kripton2035
author_rank: Super Contributor
timestamp: April 29, 2018, 08:59:57 am
content: I also had difficulties with a "simple" 3 ways 3 poles switch ...I dismantled it to finally find the correct wiring ... and as lots of springs popped up was unable to rebuild it after that !I would say you need to write down 4 tables of 5x5 entries, and in each pole entry you write the ohms betweens each way.

author: Ian.M
author_rank: Super Contributor
timestamp: April 29, 2018, 09:31:23 am
content: Start with a close visual inspection + confirmation by multimeter of the rear wafer, then see if that gives you enough to make sense of the other wafers multimeter readings
4-Switch Buck Boost DC-DC Controller Design Advice Needed (USB-C PD) - Page 1
Forum section: electronics / projects

author: chendragon
author_rank: Newbie
timestamp: March 26, 2018, 06:51:57 am
content: Hi allI'm currently working on a design for a rather powerful power-bank type application. The battery pack will be ~7s 18650 cells and the goal is to support USB Type C/Power Delivery on three ports for both input and output purposes.For those unfamiliar, USB TypeC/PD runs at 5-20V and outputs up to 4A.What this means is that I am going to need to build 3 DC-DC converters that support buck-boost for charging the battery and/or outputting the right voltage, and digital control of the voltage and hopefully current is desired for each.There is something called the OmniCharge out there that does something similar but I can't find out what type of switching controller it is using. I'm considering using the TI LM5175; previously I was going to implement a digital dc-dc converter using a FPGA but ADCs that perform well seem to be very expensive. The FPGA will probably be onboard anyway, due to other requirements.Any advice on how to go about selecting a controller for this would be appreciated.Thanks!

author: jbb
author_rank: Super Contributor
timestamp: March 26, 2018, 08:42:04 am
content: This could be fun.To make your life easier, I suggest an 8S pack so that the pack voltage is > 20 V. That way you can use buck converters, which are cheaper, smaller and more efficienct than buck-boost.Analogue control might work quite nicely. A decent synchronous buck converter with an output voltage tracking feature might work for the 5-20V output.For digital control, I would suggest a microcontroller rather than an FPGA. Writing firmware is still a pain, but much easier than writing VHDL / Verilog. To select a chip, peripherals are everything: you need good PWM (high clock frequency, hot/cold outputs and dead time) and a good ADC (say 12b 1MegSample or higher) and a hardware synchronisation line from the PWM module to the ADC.The Texas Instruments C2000 piccolo chips are quite good (good PWM, high speed ADC) for power electronics. Alternatively, I think there are some ARM chips which could fit the bill, but haven’t looked into them.

author: jbb
author_rank: Super Contributor
timestamp: March 26, 2018, 07:08:50 pm
content: Actually, Blueskull is right. You're going to be spending some money here, so full digital control is probably better.Also, you'll need some processing power to run the battery balancing and USB C port negotiations. The Piccolo chips are quite capable and could do more than just run the power converters.
4" tesla coil  2000 watts - Page 1
Forum section: electronics / projects

author: teslaman
author_rank: Contributor
timestamp: September 07, 2019, 02:57:13 am
content: My third design, based on what I considered the best traits of several plans I found online combined with a few originals. Secondary coil has spring loaded contacts on bottom so no wiring necessary to pull it apart. 26"x4" coil and 18" torus store underneath. Wheels and steering are electric scooter salvage. I don't know how much I spent on brass and nylon fasteners, can't have iron near the primary coil because of hysteresis. Uses 4 15,000v neon sign transformers (non GFCI of course) and four banks of twenty capacitors, and lots of shielding! I thought all the old house insulators and brass knurl nuts a nice touch. Primary coil is 50 feet of 1/4" copper tubing ( skin effect, you know) wound in a 2' coil on polypropylene runners on 1/4" polycarbonate sheet base. I have not started building rotary spark gaps yet, just getting started, so it is a static spark gap made from 1/4" copper lugs and 1/4" tungsten rods with a high velocity fan for a quench. You do not want to be closer than 10' from this thing when I hit the switch, and it will assault all your senses, nose (ozone like you never smelled before and nitric oxides) skin crawling, you cannot hear a person yelling right next to you the static discharge is so brutal. Next one has to be 240v 30 amp. Only thing more fun than a 8000 watt tesla coil is a 200 watt laser, good times. If there are any coilers out there, with down and dirty specs for 16,000v .50 amp trans, drop me the specs, 2 minute duty cycle, so no need to get carried away with making it super efficient.

author: teslaman
author_rank: Contributor
timestamp: September 07, 2019, 03:01:49 am
content: Terry filter and nst's

author: patrick1
author_rank: Contributor
timestamp: September 07, 2019, 07:56:09 am
content: super power

author: Gyro
author_rank: Super Contributor
timestamp: September 07, 2019, 09:19:38 am
content: Quote from: teslaman on September 07, 2019, 02:57:13 amI'm not quite sure how this squares with your aims in your other thread!Quotehttps://www.eevblog.com/forum/projects/need-plans-for-16kv-50amp-transformer-please/
4 to 20mA reading circuit. - Page 1
Forum section: electronics / projects

author: pedrovdsc
author_rank: Newbie
timestamp: December 17, 2015, 01:39:48 am
content: Hi!I'm developing a circuit to read current from a flow meter and his output is the typical 4 to 20mA. I'm thinking use a precision 250 ohm resistor - maybe 4 1k precision resistors in parallel - in series with the current source and read the drop across the resistor with an ADC. The voltage drop will vary between 1 and 5 volts.Are there any problem doing that? Have a better way to do that?Thanks!!

author: lwatts666
author_rank: Unknown
timestamp: December 17, 2015, 02:32:11 am
content: That's the way its done in the industry. Usually 250 Ohm resistor, giving 1-5V.There are two gotcha's:1) There will be a limit to how many 250 ohm devices can be in series (eg. Control System input, Local Display, etc., plus your input). Flow meter spec should define maximum output voltage it can drive, or the maximum resistance. If there is a problem, use a lower value resistor and amplify the signal accordingly.2) You have to use a differential input ADC, and it must be able to withstand the open circuit voltage of the flow meter.

author: retrolefty
author_rank: Super Contributor
timestamp: December 17, 2015, 02:35:56 am
content: Quote from: pedrovdsc on December 17, 2015, 01:39:48 amThat's the way it is mostly done. Just be sure about the loop supply polarity and how you will reference the loop common to your measurement common. Also be sure how you will mediate/protect your input circuitry what happens if your dropping resistor ever is opened (usually due to human brain fart with loop powered up) that will impress full loop voltage to your measurement input pin, usually 12-24vdc.

author: Jeroen3
author_rank: Super Contributor
timestamp: December 20, 2015, 12:09:16 am
content: You can use specialised current shunts amplifiers. You'll need an amp anyway.If you need isolation, take a look at TI's AMC1200. It will be ideal for this since you'll only need the resistor and an dc/dc brick.The real challange comes in designing such circuit that it can either do +-10Vor+-20mA by selecting a dip switch.
4 transistor 40W class A 0.0004% THD amplifier - Page 1
Forum section: electronics / projects

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: January 05, 2022, 06:42:24 am
content: The output stage is a voltage follower that I was using with an input step up transformer. I didn't tried it out yet with this configuration but only on Tina simulator.The temperature dependent CCS LM334 is mounted upon the pmos.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 05, 2022, 07:15:47 am
content: Looks like something Nelson Pass would cook up (or maybe did?). Good for keeping warm on these chilly winter months. Well, in Vietnam maybe not so much. Maybe in the mountains? Idunno.Tim

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: January 07, 2022, 06:57:07 am
content: Class A is fun and all but it's needless environmental terrorism especially at speaker level power outputs.I made a lovely valve headphone amplifier with 0.006% efficiency (1mW audio out, 15 watts of power in). Kinda stupid really.I'm going to re-use the valves from that amplifier in a Class AB amp for my turntable. The tube in a "starved anode" mode is a low voltage circuit and produces some of the fun distortions at higher volumes. There's no reason why you can't follow that with an accurate AB push-pull or even Class-D (sacrilege!) power amp.

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: January 07, 2022, 08:26:27 am
content: The above circuit can have the output replaced by a lateral mosfet complimentary pair of EXC10p/n16 biased 150ma and provide 40w with 0.002%THD at 7.5W. The problem with discrete component amplifiers bellow 50w are replaced by chips, as LM3886, only 3$ cost. when it comes to class D, only recently we got fast drivers/ GaN transistors that can achieve down to 4ns dead time resulting open loop THD of 0.007% at 1W or 100W, seehttps://www.eevblog.com/forum/projects/20bit-pwm-class-d-amplifier-idea/msg3713314/#msg3713314

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: January 07, 2022, 09:47:41 pm
content: The output, Nelsons or mine is SRPP, shunt regulated push pull circuit invented in tube era.Nelson uses two weighing resistors and a transistor making it much slower.By using lm334, I get much simpler and very fast shunt regulator.

author: BrianHG
author_rank: Super Contributor
timestamp: January 08, 2022, 01:12:23 am
content: An LM334 has more than 4 transistors in it let alone the rest in your design.Though, it is still simple...

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: January 08, 2022, 02:39:21 am
content: The LM334 serves as temperature compensator, it doesn't make part of the signal path. The zener diodes and their resistors can be replaced by voltage regulators for better PSRR.
4-wire cables, where can I find them? - Page 1
Forum section: electronics / projects

author: anfang
author_rank: Regular Contributor
timestamp: October 23, 2016, 07:46:14 pm
content: I have been making custom DC power and USB cables to attach to my boards. Right now I am connecting the plugs with jumper wires. They work perfectly but they are too loose and look horrible. I tried braiding them but then the cables become too rigid.Where can I find cables with 4 wires (copper, possibly tinned)?I tried searching on Aliexpress and ebay, but I haven't found anything. I think I miss the right search keyword.My contingency plan is to order some USB cables from Aliexpress and cut the plugs, but I fear I will receive those with cheap aluminium wires.

author: jitter
author_rank: Frequent Contributor
timestamp: October 23, 2016, 08:10:21 pm
content: Google for "4 strand wire".Or for your application, you might want to look for "4 strand shielded wire".

author: SL4P
author_rank: Super Contributor
timestamp: October 23, 2016, 08:17:40 pm
content: For USB, you want a twisted pair for data, and the power pair.There are many sources of cable online.

author: mariush
author_rank: Super Contributor
timestamp: October 23, 2016, 09:16:27 pm
content: Digikey :Cables with multiple wires inside :http://www.digikey.com/product-search/en/cables-wires/multiple-conductor-cables/1638739[ filter by number of conductors , cable thickness, if you need screening or not ]cable assemblies , ready made cables of all kinds with connectors on only one side or both etc (usb, audio etc) :http://www.digikey.com/product-search/en/cable-assembliesNewark/Farnell : (replace uk in the url with "at" to get the Austrian version of the site, with german languagecable assemblies :http://uk.farnell.com/cable-wire-cable-assemblies_cable-assembliesmulticore cable screenedhttp://uk.farnell.com/screened-multicore-cableand unscreenedhttp://uk.farnell.com/unscreened-multicore-cablemultipair cable screened or unscreened :http://uk.farnell.com/multipair-cable(pick screened or unscreened)May want to check Mouser.com as well.Since you're in Europe, TME.eu may be a good choice as well, so have a look at themhttp://tme.eu