hybridfree/eevblog-posts huggingface dataset:
How to read datasheet - webinar - Page 1
Forum section: electronics / beginners

author: Slobodan
author_rank: Regular Contributor
timestamp: October 09, 2012, 02:52:58 pm
content: Some of the forum members wanted Dave to make a video about this. He didn't (as far as I remember), so here is the alternative:http://www.eetimes.com/electrical-engineers/education-training/webinars/4375989/How-to-Read-a-Datasheet

author: ablacon64
author_rank: Frequent Contributor
timestamp: October 09, 2012, 03:35:52 pm
content: Interesting. Thanks for the link. I tried to register but it gave me an error page, is it IE only?

author: Slobodan
author_rank: Regular Contributor
timestamp: October 09, 2012, 04:14:50 pm
content: It worked just fine for me. I was using Firefox.

author: Neilm
author_rank: Super Contributor
timestamp: October 09, 2012, 07:14:55 pm
content: Looks like you have to register.Neil

author: Slobodan
author_rank: Regular Contributor
timestamp: October 10, 2012, 06:28:11 am
content: Yes you have to register, unfortunately.
How to read the value from 4 power inductors (see pictures) - Page 1
Forum section: electronics / beginners

author: ed1973
author_rank: Contributor
timestamp: May 10, 2021, 02:43:27 pm
content: Hello,I have 4 power inductors, from which I would like to know the value and I have problems reading the value. I know that the "R" sign is a decimal point, but I am not sure what's the value, when there is nothing before the R sign.Can somebody help me with this ?Attached the 4 pictures, the dimensions I measured are:1R5 : 10mm x 10mm x 3.9mm , I think the value is 1.5 uHR18D: 10mm x 10mm x 3.6mm, I think the value is 0.18 uH = 180nFR22H: 10mm x 10mm x 3.75mm, I think the value is 0.22 uH = 220nFR24H: 6.9mm x 6.9mm x 3.5mm, I think the value is 0.24 uH = 240nFAm I right ? Thanks in advance for your help.

author: Jwillis
author_rank: Super Contributor
timestamp: May 11, 2021, 03:22:51 am
content: Yes your interpretations are correct . You made a small mistake using the nF instead of nH . But it's plain to see what you mean.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 11, 2021, 04:27:01 am
content: As for current ratings, you'll have to look up comparable size and type and guess based on that. Those are composite molded chip inductors, of whatever outside dimensions. Presumably they're good to reasonably high frequencies (100s kHz), and with small values like those, they're probably running low voltage and modest current (such as you'd see in a cellphone maybe, laptop, etc.).Tim

author: ed1973
author_rank: Contributor
timestamp: May 11, 2021, 11:12:59 am
content: Thanks for your response :-)

author: Zero999
author_rank: Super Contributor
timestamp: May 11, 2021, 11:19:51 am
content: Quote from: ed1973 on May 10, 2021, 02:43:27 pmYes, other than you got the units wrong for the lower values. Inductors are always measured in Henrys (H), never Farads (F). I've fixed it for you.
How to read this schematic? - Page 1
Forum section: electronics / beginners

author: yada
author_rank: Frequent Contributor
timestamp: June 01, 2017, 01:01:42 am
content: https://www.raspberrypi.org/app/uploads/2012/04/Raspberry-Pi-Schematics-R1.0.pdfSo the Broadcom chip is broken up into several individual rectangles/blocks depending on the grouping of the pins function? How do you find where the pins go to? Match up the numbers on each line? Seems like its missing a lot for such a complex device.

author: jeroen79
author_rank: Frequent Contributor
timestamp: June 01, 2017, 01:52:43 am
content: On the inside of each block each pin's function is listed.on the outside it lists the position of the pin within a grid.(A to V and 1 to 18)http://elinux.org/RPi_BCM2835_Pinout

author: Muxr
author_rank: Super Contributor
timestamp: June 01, 2017, 01:55:50 am
content: They have the BMC chip broken up into multiple components in that schematic.. which is not uncommon for large components or components arrays. Just follow where the pins go. If a pin trace has a label on it.. that label is not just for looks. It's a netlist item. It connects to another pin or trace somewhere on the schematic with the same label.For instance:SDA0 on the BMC chip.. connects to the PH-26 header pin 3.
How to reduce current  - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: January 19, 2016, 08:30:56 pm
content: In my project I am using a transformer that has secondary current of about 700A /3V. In a certain periods I would need to cut the secondary current to about 300A only.What is the best ( easist) way to do so?

author: Simon
author_rank: Unknown
timestamp: January 19, 2016, 08:37:59 pm
content: erm, only use 300A. This is more a question of the load than the transformer, what are you doing with it ? welding ? The transformer will give what is asked of it and at 3V/300A any current limiting prractice needs to be as closely tied to management of the load as possible.

author: Jane
author_rank: Frequent Contributor
timestamp: January 19, 2016, 09:02:02 pm
content: Yes, it will be used for welding

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 19, 2016, 11:15:45 pm
content: I watchedabout how welders work. The basic idea, I gather, is that a chunk of ferrous metal is inserted into the transformer core which causes it to saturate, thereby being less efficient, and thereby outputting less current. You vary the current by varying the position of the ferrous metal.

author: Jane
author_rank: Frequent Contributor
timestamp: January 20, 2016, 07:08:19 pm
content: @jolshefsky Thank you for the interesting video
How to reduce LED lamp DC powersupply voltage to power TV backlight LED's - Page 1
Forum section: electronics / beginners

author: robsims
author_rank: Frequent Contributor
timestamp: April 20, 2024, 02:20:19 am
content: Hi, i have a TV with a damaged powersupply board. The powersupply board doesn't output power to the backlight LED's. I have a powersupply from a LED lamp that outputs 161 volts DC. I want to use this powersupply to power the LED backlights of the TV. The TV has 45 backlight LED's, so the voltage of one LED will be 161 : 45 = 3.6 Volts DC. I want to lower the powersupply's 161 volts DC output so that every LED gets 3 Volts DC. My quesion is what method can i use to lower the output voltage of the powersupply?

author: mariush
author_rank: Super Contributor
timestamp: April 20, 2024, 07:11:32 am
content: That's not how it works ...Leds have a maximum current and a forward voltage that varies with temperature of the leds and the current.For example a cold led may have a forward voltage of 3.2v , and a hot led may have a forward voltage of 3.1v ...The led driver of your monitor is configured for some maximum current, for example 80mA ... it starts to output some voltage (for example if all leds are in series, let's say 45 leds x 2.8v = 125v) and then as it monitors to current, it raises or lowers the voltage to keep the amount of current through the leds at 80mA.Your lamp driver may have the current set to 100mA or more, or may be much lower current... point is you could damage the leds by giving them too much current.A better option would be to use a universal led driver board from eBay or some place, that supports the output voltage range and current range you need.You may also want to double check, those 45 leds of your TV may split in 2 or 3 separate chains (ex 3 x 15 leds), because reducing voltage from 110v / 230v AC down to around 45v is more efficient than potentially boosting it to 150v+
How to reduce possible environmental noise when testing - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: May 04, 2022, 08:15:11 pm
content: I have a self-contained current-to-voltage amplifier circuit that I'm looking to test. I included a schematic of the amplifier below, with the elements in the dotted box being the enclosed amplifier circuit. It is sealed in a grounded box, so the inputs and outputs to it are power supply voltages, a bias voltage, the input current signal, and the output. Under regular operating conditions, the input current is in the range of nano-Amps, and I don't have any equipment that can act as a current source. The way I plan to test it is by introducing a load resistance to ground, R_LOAD. Using circuit analysis and a given bias voltage, I can calculate what the output voltage will be by adjusting R_LOAD. The output voltage will be going into an oscilloscope, represented by R5.The problem I'm concerned about is the possibility of noise at the input. The environment that I'm testing this in is quite noisy; because I'm using through-hole resistors to accomplish the testing (by using a breadboard to hold them in place), I'm concerned that they might pick up excess noise in the environment. Under normal operation, the output of the op-amp was picking up some low level 20 Hz noise which is causing problems for the rest of the circuit. The goal for this testing is to see how the op-amp circuit behaves given a clean input signal. If the output signal is clean, then we know there's something wrong with our input current signal that is introducing noise. Having the resistors on a breadboard sounds good in prototyping, but I read that breadboards can pick up unwanted noise in a circuit. Is there any way to avoid this occurrence, or perhaps there is a better way to approach this testing method?EDIT: After much consideration, I found that the best way is to use a perf-board to hold my resistors. It's a bit inconvenient, but it's non-conductive, so there shouldn't be any stray parasitic components or noise. I guess that makes my question moot. However....looking at the diagram once again, I can't help but wonder: is it possible that a voltage potential induce noise somehow? So, the PCB that my op-amp circuit is on has a copper pour tied to the BIAS voltage, not ground. This is because that was how the original current-to-voltage op-amp was designed. The op-amp and its components were "referenced" to the bias voltage, as if it were ground. The case holding op-amp is actually tied to ground, and it is electrically isolated from the PCB (there's non-conductive material holding the PCB in place, so it is not touching the case). Seeing as how there's a difference in potential from the case and the PCB ground plane, is that to be concerned about?
sleep_mode() power down breaks RF Communication - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: December 13, 2016, 05:07:23 am
content: HiI could run the LWmesh peer to peer application for my atmega256rfr2 devices.http://www.atmel.com/tools/lightweight_mesh.aspx.Now I modified the code for reducing power consumption in rf devices.The modified code for sending device is as followsCode:volatile int lastPIRsensorState=1;volatile int PIRsensorState=0;void Hibernate(){set_sleep_mode(SLEEP_MODE_PWR_DOWN);ADCSRA&=~(1<<7);sleep_enable();EICRA|=(1<<ISC00);EIMSK|=(1<<INT0);sei();sleep_disable();EIMSK&=~(1<<INT0);cli();}ISR(INT0_vect){PIRsensorState=!lastPIRsensorState;}static void appDataConf(NWK_DataReq_t *req){appDataReqBusy=false;(void)req;}static void appSendData(void){if (appDataReqBusy)return;appDataReqBuffer=PIRsensorState;appDataReq.dstAddr = 1-APP_ADDR;appDataReq.dstEndpoint = APP_ENDPOINT;appDataReq.srcEndpoint = APP_ENDPOINT;appDataReq.options = NWK_OPT_ENABLE_SECURITY;appDataReq.data = appDataReqBuffer;appDataReq.size = 1;appDataReq.confirm = appDataConf;NWK_DataReq(&appDataReq);appDataReqBusy = true;}static void appTimerHandler(SYS_Timer_t *timer){appSendData();(void)timer;}static void appInit(void){NWK_SetAddr(APP_ADDR);NWK_SetPanId(APP_PANID);PHY_SetChannel(APP_CHANNEL);#ifdef PHY_AT86RF212PHY_SetBand(APP_BAND);PHY_SetModulation(APP_MODULATION);#endifPHY_SetRxState(true);HAL_BoardInit();appTimer.interval = APP_FLUSH_TIMER_INTERVAL;appTimer.mode = SYS_TIMER_INTERVAL_MODE;appTimer.handler = appTimerHandler;}/*************************************************************************//*******************************************************************************/static void APP_TaskHandler(void){switch (appState){case APP_STATE_INITIAL:{appInit();appSendData();appState = APP_STATE_IDLE;} break;case APP_STATE_IDLE:break;default:break;}}/*************************************************************************//*******************************************************************************/int main(void){SYS_Init();PORTD=1<<PD0HAL_UartInit(9600);while (1){SYS_TaskHandler();HAL_UartTaskHandler();APP_TaskHandler();lastPIRsensorState=PIRsensorState;Hibernate();}}The device communication works well when the Hibernate() function is not called.But when this function is called it enters into a deep sleep and communicate seldom .dis sleep mode affect rf communication?What is the mistake in my code please help.
How to reinforce this through hole joint with a ripped pad? - Page 1
Forum section: electronics / beginners

author: artvandalai
author_rank: Regular Contributor
timestamp: March 04, 2025, 12:40:35 am
content: I ripped off this trace trying to solder this pin back. Any advice on how to reinforce this pin that has alot of mechanical stress to the through hole when the trace has been ripped off?

author: Jwillis
author_rank: Super Contributor
timestamp: March 04, 2025, 03:12:31 am
content: Copper or Bronze PCB Rivets. You can get them from .8mm to 5mm inside diameter.

author: wraper
author_rank: Unknown
timestamp: March 04, 2025, 03:32:31 am
content: Do not bother with the pad, use neutral silicone adhesive to hold the part in place instead.

author: inse
author_rank: Super Contributor
timestamp: March 04, 2025, 06:04:46 am
content: When you pull or push the connector, the pin will come loose again, silicone won‘t hold it back.Stabilize the pin on both sides with good epoxy glue e.g. JB Weld

author: artvandalai
author_rank: Regular Contributor
timestamp: March 04, 2025, 06:14:21 am
content: Will uv glue work or use epoxy instead?

author: benj38
author_rank: Frequent Contributor
timestamp: March 04, 2025, 08:17:00 am
content: Epoxy is better in this application, but UV glue should also work.Use a jumper wire soldered on one end to the pin, and the other end to another component pad on this PCB trace that was lifted. The wire will serve as a flexible backup to the trace, so even if things move, the pin will still be electrically well connected.
How to remove components from tape easily? - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: April 21, 2014, 06:40:49 pm
content: I've got a whole bunch of 100 mil spaced 100nF capacitors that I'd like to get removed from the tape which looks like cardboard on one side with holes in it and perhaps 5/16" masking tape on the other side holding the component.I've cut them, I've pulled them, both of which get old quick - do you guys have a better way?

author: 8086
author_rank: Super Contributor
timestamp: April 21, 2014, 06:42:52 pm
content: There are machines to do this but they are silly prices usually.I deal with a few hundred a week on tape and I just cut them.

author: Weisserrabe
author_rank: Newbie
timestamp: April 21, 2014, 06:43:30 pm
content: keep cutting them, because you don't want the gunk of the tape on your leads when you solder them later

author: ElektroQuark
author_rank: Unknown
timestamp: April 21, 2014, 07:05:50 pm
content: If yo have a lo of them to cut, one of these cheapo can help:

author: SeanB
author_rank: Super Contributor
timestamp: April 21, 2014, 07:12:15 pm
content: Just grab the kitchen scissors and do a dozen at a time.

author: Simon
author_rank: Unknown
timestamp: April 21, 2014, 07:23:34 pm
content: well if it's through hole your talking surely you can just pull them off. the ends need cutting once they are soldered anyway

author: David_AVD
author_rank: Super Contributor
timestamp: April 21, 2014, 08:52:01 pm
content: Since we don't need to do this often, we use a pair of tin snips. Can cut 6 or so at a time and the blades don't mash the cut end.If we had a lot of them to do I'd buy a radial cutter machine. The axial cutter (and bender) machine we have does 1000 resistors in under a minute.

author: con-f-use
author_rank: Unknown
timestamp: April 21, 2014, 08:57:06 pm
content: Has anybody tried to soak the paper in soap water, alcohol or acetone? The only time I ordered a few components packaged like that, it was 20 MOVs. I picked them out by hand but I can see how it is annoying as Phuq.

author: gibbled
author_rank: Regular Contributor
timestamp: April 21, 2014, 09:16:02 pm
content: I've used mineral spirits/paint thinner to remove the goo after pulling the tape off.

author: alank2
author_rank: Super Contributor
timestamp: April 21, 2014, 10:00:42 pm
content: Quote from: EdoNork on April 21, 2014, 07:05:50 pmYES!!! This method rules. Just knocked out 500 caps quickly and easily!Thanks everyone.
How to remove hot glue? - Page 1
Forum section: electronics / beginners

author: obiwanjacobi
author_rank: Super Contributor
timestamp: February 22, 2015, 10:34:43 am
content: Is there a trick to removing hot glue from parts and PCBs with SMD?I fear that if I start pulling I might rip some SMD components from the PCB.

author: Psi
author_rank: Super Contributor
timestamp: February 22, 2015, 10:39:00 am
content: Use hot air to melt it and wipe it off gently, then repeat.

author: wraper
author_rank: Unknown
timestamp: February 22, 2015, 10:46:41 am
content: Put it in the freezer. Then while it still cold, poke the glue, it will just fall off without leaving residue. Of course this will work if this is really the hot glue, not some kind of silicone.

author: obiwanjacobi
author_rank: Super Contributor
timestamp: February 22, 2015, 11:10:54 am
content: Hahaha one answer for each end of the spectrumThanx guys!

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: February 22, 2015, 12:23:08 pm
content: Isopropyl alcohol will do the trick. Just use a swab and rub it around the edges of the glued object and or the glue you want to remove and it will come right off. If you Google this you can find videos and all kinds of articles on the hows and whys. Hope this helps!

author: electr_peter
author_rank: Unknown
timestamp: February 22, 2015, 12:32:35 pm
content: Quote from: Terabyte2007 on February 22, 2015, 12:23:08 pmIPA works for plastic/flat surfaces very well.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 23, 2015, 07:20:26 pm
content: Cheap hot snot comes off without any stick poking, but real brand hot snot can be a bugger. I would suggest rubbing alcohol as someone else did.

author: PeterFW
author_rank: Frequent Contributor
timestamp: February 23, 2015, 11:33:52 pm
content: Quote from: electr_peter on February 22, 2015, 12:32:35 pmYep, i have not met a type of hot glue that likes isopropanol.Either is will come of as a whole piece or it gets crumply and can easily be removed with a brush or poker.First time trying this method i was stumped how well isopropanol works.I got a big cannister of denatured ethanol and isopropanol for various tasks, no one should be without a good amount
How to remove solder from standoffs? (Picture Included) - Page 1
Forum section: electronics / beginners

author: brokenbones
author_rank: Newbie
timestamp: October 06, 2025, 06:17:57 pm
content: 1. What do you call these standoffs that hold solder and leads?2. How do you remove the solder to get the component out?TIA

author: Swake
author_rank: Frequent Contributor
timestamp: October 06, 2025, 07:36:32 pm
content: With a de-soldering gun.Are these accessible from the other side? If not remove the component first by melting with a 'big' iron and then use the sucker to empty the tube. You might have to add some new solder before it sucks up.
How to replace  PIC16F676  with Arduino/ESP32? - Page 1
Forum section: electronics / beginners

author: mrnams
author_rank: Newbie
timestamp: September 15, 2023, 12:41:48 pm
content: Hello All,I have auto switch for 3 Phase DOL starter with current sensor (using CT) and is working fine, i.e. is sense current and stop motor if it takes more current, it stops motor one phase failure, it working as expected, i just want to control it using ESP32 so that I read values and send it to cloud and based on that values give command to ESP32 to operate particular relay.So, I want to remove PIC16F676 and use Arduino/ESP32. I know its hard to understand,what inputs given to PIC16F676, I want give a try.

author: Ian.M
author_rank: Super Contributor
timestamp: September 15, 2023, 02:16:56 pm
content: I'd bet the PIC16F676 can respond to a severe overload in under a millisecond, certainly in less than one mains half-cycle. Good luck getting an ESP32 + Arduino framework to do that with concurrent cloud connectivity without diving into assembler to write the ISRs.For the sake of your sanity *keep* the PIC16F676 and set its trip current appropriately as a max. limit. Then at least any unexpected delays in your code wont burn the wiring and are less likely to burn the motor. You may be able to tap into the same current sensors without affecting the PIC16F676 and can share the same contactor.
How to represent negative voltages in schematics? - Page 1
Forum section: electronics / beginners

author: vmallet
author_rank: Regular Contributor
timestamp: August 20, 2020, 12:49:56 am
content: The circuit I'm looking at now has +12V and -12V and I am not sure how to properly represent these in a schematic. Attached is an example where the power comes to the board through a header. I can see two ways of representing that but I'm not sure which one is the most "common" or if there are other ways to draw these.Thanks!

author: ledtester
author_rank: Super Contributor
timestamp: August 20, 2020, 01:54:11 am
content: For -12V you could use the +12V port symbol rotated 180 degrees.

author: TimFox
author_rank: Super Contributor
timestamp: August 20, 2020, 03:47:02 pm
content: All of them are understandable, but you should use the same arrowhead for both positive and negative. Ground symbols look ugly pointing up, so your use of down-pointing symbols for ground/common is preferred.

author: Zeyneb
author_rank: Regular Contributor
timestamp: August 20, 2020, 11:52:08 pm
content: If you have space in height you might want to stack the capacitor/resistor on top of each other. It is quite common to have ground in the middle (maybe even a horizontal line). Positive voltage nodes above the ground line and negative below the line.
How to route differential pairs? - Page 1
Forum section: electronics / beginners

author: shai
author_rank: Contributor
timestamp: January 04, 2019, 01:21:31 am
content: Background: I'm making an OpenPNP pick and place board that runs on smoothieware. I am creating a USB 2.0 Hub (since LPC1769 chip uses USB 2.0) for the two cameras and smoothie so I can connect my machine using one USB cable instead of three. I've already tested it and it works.I have an FFC connector that runs to the head of the PNP head. Two of the traces on the FFC are for the downward facing camera. This FFC connector needs to be placed where it is currently on the board (assume I cannot move it) and assume the HUB on the right side in the attached pictures also cannot be moved.What's the best way to route the differential pairs from the FFC on the left to the Hub Controller on the right?The board is 4 layer board (from top to bottom):TOP (traces) with GND pourGND pour onlyVCC (12V pour, 3.3v pour)BOTTOM GND pour (with traces)I was thinking of routing these pair of differentials on the bottom of the board where there's no components (ok, it goes under a few components on the left side only).Am I transferring between layers correctly?I did some research but couldn't find much on how to transfer differential pairs between layers correctly.. or is it fairly simple? Any help appreciated!! The lengths are matched 100%P.S. Would this long routing from left to right for the downward camera work in theory? lolSee attached images.

author: ataradov
author_rank: Super Contributor
timestamp: January 04, 2019, 01:34:55 am
content: It is only Full-Speed USB, you will be fine. You also don't need that length matching kink in the trace. Place a row of vias along the pair, you seem to have plenty of space for that.

author: shai
author_rank: Contributor
timestamp: January 04, 2019, 01:40:16 am
content: What's the purpose of placing the Vias along the traces on the sides? Should they be GND and 12V Vias on opposite sides? Can you show a quick drawing to make sure I understand correctly?

author: ataradov
author_rank: Super Contributor
timestamp: January 04, 2019, 01:42:29 am
content: Quote from: shai on January 04, 2019, 01:40:16 amBoth sides should be grounds, at least along the USB traces. They will forms a "shield" of sorts, preventing EMI from both sides.I assume you have ground polygons on both sides. Because that is something you should actually do. Then just place a bunch of vias along the traces.Here is a random picture from Google to illustrate the idea. But there is no need to have them this dense, every 1/4"-1/2" will be sufficient and won't annoy your board house.
how to safely charge 18650s with 5v supply connected in series?  - Page 1
Forum section: electronics / beginners

author: stormrazer121
author_rank: Newbie
timestamp: May 17, 2023, 09:18:41 am
content: Confusing title i know! i will try explain this as best i can.I am building a portable speaker, i want to be able to use 18650 cells but charge them from a normal USB wall socket aka 5v USB micro b for example.The problem I'm running into is this, The i don't want the output of the 18650 cell to be 3.7-4.2v, i want to boost that voltage to 12v by running 3 18650 cells together, i understand that this means i need a BMS, what i am trying to get my head around is if i do this then i would need1. a BMS to safely charge the 18650 cells2. a separate charger PCBSo if my understanding is correct the BMS will make sure the battery's are charged safely and the charger PCB would be the one taking control of current control etc right?This then moves onto the next dilemma that i need to address, I want to be able to power this all from a normal USB cable, I'm okay with it taking longer than normal to charge i just want it to be safe!So would doing what i am attempting be safe? or.....would i need to add a boost converter between the Charger PCB and the BMS to get the correct voltage? if so what would be the right steps to take to make sure it is done right?Thanks guys

author: tunk
author_rank: Super Contributor
timestamp: May 17, 2023, 10:30:51 am
content: It may be simpler to put the 18650s in parallel and use a boost converterto get 12V. Then you can use a simple BMS and e.g. a TP4056 module forcharging. And a BMS does not control charging, it controls overcharge,overdischarge and overcurrent.

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 17, 2023, 12:33:24 pm
content: Most efficient way would be to use a step-up 3s charger controller, you also need cell balancing when changing in series.For example:https://a.aliexpress.com/_Ezi3rbbIt uses ijoinic IP2326 controller, attached chinese datasheet.(Pretty hard to find the newer version, old one was only 2S).It's not clear to me how it manages 3S balancing...

author: stormrazer121
author_rank: Newbie
timestamp: May 20, 2023, 06:43:21 pm
content: Quote from: tunk on May 17, 2023, 10:30:51 amNot possible, I have already tried that and all Boost convertors I used cause the amp to cut out due to amp draw being higher than 2ampsQuote from: DavidAlfa on May 17, 2023, 12:33:24 pmHm, I would be cautious with this for a number of reason, I'm no engineer but I also like to be extra safe when it comes to safely charging and discharging Li-ion hahaI am still stuck and so far the BMS is something I know I need, its just managing to charge that with simple USB, I suppose I could but it would be silly slow if I used a boost convertor, I'm just stuck!I would use that chip but I don't have the equipment necessary to test it to see if its overvolt/charge and undervolt etc all work properly.
How to safely o'scope Dell laptop adapters - Page 1
Forum section: electronics / beginners

author: 13hm13
author_rank: Frequent Contributor
timestamp: December 08, 2013, 09:34:07 am
content: In EEV Blog #279, (at 09:25) Dave noted that his Dell laptop adapter has roughly 1K-ohm between mains earth (ground) and DC negative. This sets up a potentially hazardous situation for many o'scopes.Dell makes great laptops (IMO) but their adapters are notorious for failing or getting noisy. So I have two basic question:(1) WRT to the discussion of o'scope safety, how do I SAFELY use my Tektronix 465 (classic 1976 analog 'scope) with a now-failing Dell laptop adapter (it's similar to the one Dave showed in the episode -- i.e, it is three-prong with an mains Earth prong).(2) The "failing" adapter can be heard over the audio signal in terms of audible noise -- I have no noise using another (good) adapter; and with the "failing" one, I can make the noise go away for a while by gently (physically) tapping. It's been like this for several mos., but the adapter does now seem to be getting any worse -- i.e., a gentle tap every few days and I'm good to go until the noise comes back (after 3-4 days ... then just hit it again.TTBOMK, related to the noisy adapter, I have not noted any (non-audio) other glitches in this laptops performance (its an Inspirion 1764, Win 7 laptop from July 2010). I am concerned that if I can hear the (switching?) noise, it's probab. not good for myriad other components comprising this laptop. Damage that "accumulates" over time. And this is why I want to SAFELY o'scope the adapter.Thx!!

author: Psi
author_rank: Super Contributor
timestamp: December 08, 2013, 09:44:36 am
content: Run the laptop (power adapter) from and isolating transformer while working on it with the scope.
How to sample 8 pins at 24 MHz and detect for 50ms periods... - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: April 14, 2016, 01:26:28 am
content: How to sample 8 pins at 25 MHz and detect for 50ms periods:all lowall highmixed high and lowI want to make a logic probe type of thing that indicates the state of 8 lines. The 50ms limits the LED changes to 10 Hz which is easily visible. This way a quick pulse that you would never see in the LED would be visible.What components would you recommend that can detect as small as a 40ns change (25 MHz)? I don't need to know how many - just sample for 50 milliseconds and each line needs LOW, HIGH, or MIXED.

author: alank2
author_rank: Super Contributor
timestamp: April 15, 2016, 12:19:31 pm
content: Thanks evg149 - I actually found a way to do it very efficiently with an xmega. The gpio's on it have pin sensing so you can sense both edges on them using INTFLAGS after setting INTMASK for them. I am doing the entire port. Once I enabled the internal 32MHz clock, I can sense an edge at 35ns consistently!!
How to save footprint library in KiCAD - Page 1
Forum section: electronics / beginners

author: MrOmnos
author_rank: Frequent Contributor
timestamp: August 14, 2016, 10:21:50 am
content: SO, I made a component and used it in my schematic. I generated the net list and associated the footprints for the parts that were already in the library. Now I need to create the footprint for the part I created. I opened pcbnew and created a new footprint. Saved it in new library. And I can see it is saved in a .pretty folder. But it doesn't show up in the cvpcb? How do i associate it with my part? I have wasted hours looking for an answer, some talk about Git, some say 'restart you KiCAD', no concrete answer.

author: Thor-Arne
author_rank: Unknown
timestamp: August 14, 2016, 03:43:50 pm
content: If you saved your footprint to a new library you need to add that library to the fp-lib-table.From pcbnew, "Preferences" -> "Footprint Libraries Manager".Add your library there.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: August 14, 2016, 08:26:06 pm
content: The procedure for adding a custom part in eeschema and pcbnew is very similareeschema:1) Open eeschema2) Open library editor3) Create new component4) Save component in a new library5) Back in eeschema, add the new library to the projectpcbnew:1) Open pcbnew2) Open footprint editor3) Create new footprint4) Save footprint in a new library5) Back in pcbnew, add the new library to the projectIt sounds like it's that last step you're missing. And of course, once you've added the new library to the project, from then on you can just save the parts in it. I have noticed that you need to restart KiCAD before the new footprints will show up in CvPcb though.

author: alexanderbrevig
author_rank: Frequent Contributor
timestamp: August 15, 2016, 01:25:14 am
content: Hope your problem is resolved! If you want more help with KiCAD you will probably have luck here too:https://www.eevblog.com/forum/kicad/
How to Save Outgoing PM? - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 12, 2010, 04:46:29 pm
content: maybe i'm the stupid or the ignorant crap. But just how to save the Outgoing Private Message into our Outbox? my outgoing PM just simply vanished after i click send button

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: October 12, 2010, 04:51:07 pm
content: On the left side of the "MY MESSAGES" screen there is both an inbox and an outbox. My outbox has a copy of every PM I've sent.

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 12, 2010, 06:31:10 pm
content: mine is empty! even just after sending a PMmaybe i've set something wrong?

author: Time
author_rank: Frequent Contributor
timestamp: October 12, 2010, 06:32:02 pm
content: print and file for later use

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: October 12, 2010, 06:40:40 pm
content: Go to "PROFILE" on the tab above.On the left edge at the bottom you'll see "Personal Message Options" ... click it.Toward the bottom is a check box for saving your messages.

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 12, 2010, 06:58:48 pm
content: settled. as i said, stupid me!. thanx John.
How to search for a gearbox? - Page 1
Forum section: electronics / beginners

author: SenSeS
author_rank: Contributor
timestamp: June 15, 2015, 12:47:33 pm
content: Hi all,I've found a motor (I think) that fits my requirements. However I'm trying to find a spur gearbox (1:150) that goes along with it. How is this usually done? It seems that I can't find a general approach to this. When taking apart products with gearboxes I usually see one of 2 possibilities. 1) the gears are big, generally plastic, and spread across the product (printers, scanners, etc). 2) there is a custom gearbox designed that looks like something you would get when buying a geared motor but then placed in a special order or shape to fit the product. Are these the 2 prevailing options in commercial products? For a hobbyist project this is pretty expensive. It seems that there is no real collection of "standard" gearboxes that I can just attach to my motor. Ideally I would want the following shape of gearboxThe reason for this is cause it needs to be as short as possible. A worm wheel could work but is very inefficient. I'm currently looking at a Mabuchi DC motor. Thank you for your help!

author: PSR B1257
author_rank: Frequent Contributor
timestamp: June 15, 2015, 04:32:22 pm
content: QuoteWhy such a high ratio? Can't you use a different motor to start with?Whats the application?QuoteUsually this does not really matter, if you have to choose a worm gear.Why did you not buy a gear motor directly?

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: June 16, 2015, 03:16:18 am
content: Have a look at McLennan gearboxes, spur gearboxes, ovoid instrument units...or such like. I have used them in telescope drives. But they are not that expensive..well not for what I want.http://www.mclennan.co.uk/products/gearboxes-speed-reducersI didn't see a 150:1 but they might in their other ranges although Polo has some:https://www.pololu.com/product/2368Also Maxon motors may have what you want but they cost a lot. Most motor suppliers have gearbox options these days so it's best to search for a gearbox AIO using the motor mfgrs as a base.

author: FrankT
author_rank: Regular Contributor
timestamp: June 21, 2015, 09:19:50 pm
content: I find it is easier to find the motor+gearbox combo. I don't know what your price range or precision requirements are, but super droid robots have a great range of motors with/without gearboxes, with/without encoders...http://www.superdroidrobots.com/shop/category.aspx/gear-motors/7/

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 22, 2015, 12:50:02 am
content: Without torque or power or something to give me an idea of what to look for, I'd send you to Hobby King to search for sail winch servos.
How to select uC for motor control  - Page 1
Forum section: electronics / beginners

author: sean87
author_rank: Regular Contributor
timestamp: September 18, 2017, 07:35:16 am
content: Hi! I am completely new in motor control. I want to create a low-cost motor control for BLDC (brushless DC) that comes with HAL sensors. There are 2 motors that should be controlled independently. I want to use 2x TI DRV8323 as the drivers. My question is, what kind of peripherals the microcontroller should have. E.g:- Number of timers (I beleive 3 PWM signals per motor is a must?)- What peripheral should be used for HAL sensor? ADC or digital input logic?- Is there anything I am missing?I have some nucleo boards sitting around. The datasheet reads:16x timers: 2x 16-bit advanced motor-control, 2x 32-bit and 5x 16-bit general purpose, 2x 16-bit basic, 2x low-power 16-bit timers (available in Stop mode), 2x watchdogs, SysTick timer.So,l 2x16bit advanced motor-control means I can safely choose this chip for controlling the 2 motors I have?

author: Benta
author_rank: Super Contributor
timestamp: September 18, 2017, 08:38:41 am
content: There are lots of MCUs with dedicated 3-phase timers for motor control. Advantage is, that they have hardware fault protection of the power stage. This is crucial, specially when debugging. You can't single-step a motor control application without letting the smoke out of the power stage.

author: sean87
author_rank: Regular Contributor
timestamp: September 18, 2017, 08:56:28 am
content: Quote from: Benta on September 18, 2017, 08:38:41 amThanks for the feedbackcan you please name one of those MCUs? I really have no idea. Also, since HALL sensor will make this a closed-loop-system...what is your opinion about the amount of processing power required?

author: Benta
author_rank: Super Contributor
timestamp: September 18, 2017, 09:34:58 am
content: Forget my previous post, I missed the reference to DRV8323.In this case, you just need an MCU that can generate a PWM signal. Everything else the DRV8323 takes care of. No processing power really required apart from setting up a PWM timer.
How to simulate DC characteristics of a 5 terminal MOSFET? - Page 1
Forum section: electronics / beginners

author: tec5c
author_rank: Frequent Contributor
timestamp: February 06, 2017, 11:39:28 pm
content: Hi all,I have a model of a 5 terminal MOSFET; Drain, Source, Gate, Body, Substrate, that I am trying to simulate its DC characteristics (IV curve). I know for certain that the Body is not tied to the Substrate terminal but I am unsure on what I should do here to get the sim working.Any advice on how I can simulate such a model? I am working in LTSpice.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 07, 2017, 03:03:06 am
content: Well, do whatever the datasheet tells you to do... You've told us basically nothing about it, so we can only make vague guesses.On the upside, you can't burn any parts by wiring it up randomly. Give it a try...Tim

author: danadak
author_rank: Super Contributor
timestamp: February 07, 2017, 11:45:38 am
content: Not clear to me the difference between body and substrate connection.In short the substrate normally connected to source terminal. If it is connectedto another bias point where the Vbias is not same as Vsource that affects thethreshold voltage of the MOSFET.Called the body effect or source bulk effect.https://en.wikipedia.org/wiki/MOSFETRegards, Dana.
how to simulate mc34063 in proyeus - Page 1
Forum section: electronics / beginners

author: poohpary
author_rank: Contributor
timestamp: July 10, 2013, 03:29:54 pm
content: i tried to simulate boost converter in proteus but its simulation takes too much time to be done....i dont know whats the problem...is there any one to help me plz?

author: c4757p
author_rank: Super Contributor
timestamp: July 10, 2013, 04:02:36 pm
content: Switchers are always slow, especially if your computer isn't great. I just let a simulation + automated analysis of a UC3843-based SEPIC run overnight! Be patient.Also, try other software. LTspice is pretty quick.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 10, 2013, 04:34:07 pm
content: You could ask in the excellent Proteus support forum over at Labcenter.

author: poohpary
author_rank: Contributor
timestamp: July 10, 2013, 04:48:24 pm
content: thanks for reply....are u sure it is natural to takes that much time ? cause i thought maybe i should change time step or sth which dis not affect ...what a bout pspice....can it simulate mc34063 ?

author: c4757p
author_rank: Super Contributor
timestamp: July 10, 2013, 04:59:20 pm
content: All SPICE can simulate a SPICE model.One key piece of info here: how long is 'this much time'?

author: poohpary
author_rank: Contributor
timestamp: July 10, 2013, 05:08:19 pm
content: 10 min for 0.1ms time response !! (do not tell me it is not that much time...!!)

author: c4757p
author_rank: Super Contributor
timestamp: July 10, 2013, 05:34:53 pm
content: No, for a simple MC34063, that is way too much time. I just simulated the same circuit in LTspice and it took one minute to do 21ms.

author: poohpary
author_rank: Contributor
timestamp: July 10, 2013, 08:13:42 pm
content: what kind of capacitor and inductor did you use? by that time! ... output had big ripples....and it was not suppose to be...
How to simulate MOSFET gain? - Page 1
Forum section: electronics / beginners

author: fourierpwn
author_rank: Regular Contributor
timestamp: May 29, 2017, 08:53:45 am
content: Hi,I am wanting to find out the gain of any given MOSFET device in LTSPICE. I am not certain of the schematic setup needed as well as the simulation command.Any help is appreciated.

author: Zero999
author_rank: Super Contributor
timestamp: May 29, 2017, 09:21:18 am
content: Quote from: fourierpwn on May 29, 2017, 08:53:45 amWhy do you need to do this?What do you mean by gain?If you mean voltage gain, then that's purely dependant on the circuit and has little to do with the MOSFET.If you're referring to the change in drain current vs gate source voltage, then that's known as transconductance and the answer will be in the model you're using.

author: danadak
author_rank: Super Contributor
timestamp: May 29, 2017, 12:47:20 pm
content: This might help -http://learn-ltspice.weebly.com/uploads/2/5/5/2/25523252/mosfet_amplifier.pdfRegards, Dana.
How to size a capacitor for a bunch of led's - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: April 21, 2015, 01:24:05 pm
content: Hi Everyone,I'm thinking of making a ht1632c based display using the ltp-305's from digikey/mouser that are a 5x7 matrix with decimal point. I like these displays because they are somewhat old style with led's shaped in a matrix encased in plastic. This is a for fun project. Because of the way the ht1632c multiplexes I'm going to use 24x16 mode which allows me to drive 8 digits, 4 wide (6 columns each) x 2 rows (14 rows). 3mA average for each dot is fine, so the pulse for each of the 24 will be 3mA*16 or 48mA. 0.048*24 leds is 1.152A, so it might go from needing 1.152A for all led's on and 0A for all led's off. In practice, I plan to use a standard 5x7 character set which will typically not involve all being on at the same time. How do I size a capacitor for the display board that can handle this?Thanks,Alan

author: alank2
author_rank: Super Contributor
timestamp: April 21, 2015, 03:56:03 pm
content: Is there a formula to figure out this type of thing?
How to size FETs? - Page 1
Forum section: electronics / beginners

author: redgear
author_rank: Frequent Contributor
timestamp: August 08, 2019, 08:58:00 am
content: TI's design resources say :QuoteI will be using a 6S pack, so my DC voltage should be 30V and transient should be 60V.QuoteHow do I calculate the current requirements? My motor draws a max of 15A and I'm yet to calculate the current required for the display and other parts.The design uses two FETs in parallel to increase thermal performance, do I need to use two FETs for the low current applications like mine?

author: ratatax
author_rank: Regular Contributor
timestamp: August 08, 2019, 09:13:28 am
content: For the thermal side :On the datasheet you should have a line telling you how many °C the part increase relative to ambient temperature for each Watt of power dissipiation. Calculate the power dissipation using the internal FET resistance, the voltage and current needed.If the temp rise (°C) is too much, you need a heatsink or split the current with multiple FETs in parallel.I think you can ignore the current needed by the display, it should be peanuts compared to the 15A needed by the motors

author: Kleinstein
author_rank: Super Contributor
timestamp: August 08, 2019, 12:23:27 pm
content: Is the FET also switching the display ? Normally the display and control part would not be switched together with a motor.For the choice of FET the frequency is an important factor. For just occasionally switching in an on/off way, the FETs can be relatively large (high current). For a higher frequency switching like fast PWM, high frequency SMPS the switching losses are important and just large enough it not good. Larger FETs will have more switching loss.

author: redgear
author_rank: Frequent Contributor
timestamp: August 13, 2019, 05:27:48 am
content: Quote from: ratatax on August 08, 2019, 09:13:28 amOk, Thanks! How much is too much? >50 deg C?Quote from: Kleinstein on August 08, 2019, 12:23:27 pmNo, FET does not switch the display!QuoteYeah, I read that but idk how to what I can do to make it better.
How to size Schottky thermal for a bridge rectifier - Page 1
Forum section: electronics / beginners

author: Frederico Acardi
author_rank: Contributor
timestamp: March 07, 2019, 02:09:16 pm
content: Hello.I want to rectify 360V@350mA secondary.I will use 4 TO220 sic schottky rectifier rated @1200Vrrm.Ir at rated Vr (Typ) = 10µA/25° 40µA/150°Ir at rated Vr (Max) = 50µA/25° 150µA/175°Datasheet :https://www.wolfspeed.com/media/downloads/75/C4D02120A.pdfI am aware of theTj runawaybut how do I calculate the requirements to avoid exceeding the power dissipation of the diode ?Thank you.
Delete Delete Delete - Page 1
Forum section: electronics / beginners

author: The_Almighty_Bacon_Lord
author_rank: Contributor
timestamp: July 05, 2018, 01:16:55 am
content: Delete Delete Delete

author: sokoloff
author_rank: Super Contributor
timestamp: July 05, 2018, 01:36:44 am
content: By far the easiest course to get a sine wave output is to buy a UPS with sine wave output. (Never build something that you can readily and affordably buy in the commercial market.)It’s not necessary though for devices with switching power supplies.

author: digsys
author_rank: Unknown
timestamp: July 05, 2018, 01:49:16 am
content: As mentioned, it's NOT worth it ! There is a huge difference in technology, going from Square wave, 3>multiple step mode and full resonant / synchronoussine wave. If the HF pulses cause you issues, you may be able to add a big-ass inductor in series, but that will introduce heating and other issues.

author: digsys
author_rank: Unknown
timestamp: July 05, 2018, 02:30:11 am
content: Sorry .. NOPE ! Not even close.