hybridfree/eevblog-posts huggingface dataset:
Starting oscilloscope? - Page 1
Forum section: electronics / beginners

author: SurprisingRice
author_rank: Newbie
timestamp: July 20, 2015, 01:01:40 am
content: Hi, im here to ask what would be a good starting digital oscilloscope, Price range 0-300$.

author: ez24
author_rank: Super Contributor
timestamp: July 20, 2015, 01:40:35 am
content: My vote:$60 = DSO112 from Singapore (not China). I am happy with mine.$279 = a Siglent model (I do not have one)$375 - everyone is going to say - save up another $75 and get a Rigol DS1054 - once you decide, ask where to buy. I am happy with mine and it keeps my DSO112 honest. No regrets.Do a search on this forum for DS1054z and you will get one million hits because it is the most popular.This leaves a gap from $60 to $280 that I do not know how to fill. The only thing I can think of is maybe there is a Pico USB in that price range. I think also there is a Hantek USB in that range.Summary (low to high):- DSO112- Hantek USB- Pico USB (maybe)- Siglent- Rigol DS1054z (but over $300)

author: rgawron
author_rank: Contributor
timestamp: July 20, 2015, 01:43:09 am
content: If you would add another 100$ (I know it's 25% more that what you may spend), you could buy DS1054Z, it's quite a new product, but has good opinions.http://www.rigolna.com/products/digital-oscilloscopes/ds1000Z/ds1054z/

author: SurprisingRice
author_rank: Newbie
timestamp: July 20, 2015, 01:54:42 am
content: Hm.. Seems like if I put up the extra dollar now I'll be set for the future better, so I think I'll go for the DS1054Z, thanks so much guys!

author: Lightages
author_rank: Unknown
timestamp: July 20, 2015, 03:04:23 am
content: Good decision.

author: lapm
author_rank: Frequent Contributor
timestamp: July 20, 2015, 10:25:54 am
content: Good choise. DS1054Z Would be my choise if i would be buying DSO. I have nice analog that goes 60 MHz.. Got it used at reasonable price.
Starting out with BLE - can multiple services be advertised? - Page 1
Forum section: electronics / beginners

author: dvh
author_rank: Contributor
timestamp: March 04, 2024, 08:33:02 am
content: Hello everyone!I'm working on a tiny project where I'd like some connectivity between my phone and a BLE enabled devboard (ESP-WROOM-32). Ideally, it'd be a non-connectable, undirected broadcaster with pieces of sensor data embedded in advertisement packets.I've been digging through some arduino BLE libraries and found a wrapper aroundmyNewt nimbleforArduino.Right out of the box, I got into problems with advertising multiple services. Here is my code:Code:#include <NimBLEDevice.h>// https://www.uuidgenerator.net/#define SERVICE_UUID1 "4fafc201-1fb5-459e-8fcc-c5c9c331914b"#define SERVICE_UUID2 "525bb0f4-7856-47d8-8f92-7f209aa3fb2e"static NimBLEUUID serviceID1(SERVICE_UUID1);static NimBLEUUID serviceID2(SERVICE_UUID2);static NimBLEAdvertising *pAdvert = nullptr;static uint32_t count = 0;void setup() {Serial.begin(115200);Serial.println("Starting BLE work!");NimBLEDevice::init("SmartPot");pAdvert = NimBLEDevice::getAdvertising();}void loop() {pAdvert->stop();pAdvert->setAdvertisementType(BLE_GAP_CONN_MODE_NON);pAdvert->setServiceData(serviceID1, std::string((char*)&count, sizeof(count)));pAdvert->setServiceData(serviceID2, std::string("bleh"));pAdvert->start();Serial.printf("Advertising count = %d\n", count);count++;delay(5000);}Questions:Am I correct assuming that it should be possible to advert multiple 128 bit services with data by the spec?Could it be that it's the wrapper that does something weird for which reason the code sample doesn't work?Do you have experience with that library? Should I keep investing time learning it or should I go straight to ESP-IDF?Do you have recommendations for a decent higher level abstraction for working with BLE & Arduino?Thanks in advance!

author: Smokey
author_rank: Super Contributor
timestamp: March 04, 2024, 08:43:23 am
content: https://docs.silabs.com/bluetooth/2.13/general/adv-and-scanning/bluetooth-adv-data-basics

author: dvh
author_rank: Contributor
timestamp: March 05, 2024, 08:52:08 am
content: That didn't help much.But I managed to piece together from other sources that there is a 31 octet limit on the size of the advert packet. If I want to advertise multiple services, I have to implement scan response too.
Starting out with RF Engineering - Page 1
Forum section: electronics / beginners

author: DrLuke
author_rank: Contributor
timestamp: February 23, 2014, 08:14:17 pm
content: Hello everyone!I am in third semester at Uni studying EE. The dry theory is getting on my nerves, so I am trying to apply some of it where possible. I already have some experience with microcontrollers and basic analog electronics, but none with RF yet. Ergo I am trying to expand in that direction now.The first thing I want to do is build a simple RF transmitter which allows me to shift the frequency a little bit so I can transmit simple data packets. The Problem I am stuck with is the VCO. I've looked all around the internet to see if there are ready to go VCO modules, but the only ones I could finde were over 30$ a pop, which is way too much for me.Can anyone point me in the right direction? I was thinking about using 433 MHz as a frequency, since that's a license free band. As the frequency shift, I would like to see a shift of a couple kHz at most, so I could theoretically just listen to the audio output on my SDR dongle.Cheers,DrLuke

author: SeanB
author_rank: Super Contributor
timestamp: February 23, 2014, 08:32:25 pm
content: Use a varicap diode to do the FSK direct with the RF oscillator. Pretty much any signal diode will do as a demo, but you can get proper low capacitance varicaps ( 2-20pF) if you want to try. Easy enough to roll your own varicap one you have the inductor and tuning capacitor and use the varicap to add a little more capacitance.
Starting out - Page 1
Forum section: electronics / beginners

author: Vintage1873
author_rank: Newbie
timestamp: October 08, 2016, 09:37:43 pm
content: Hello everyone, I'm new to the forum and I'm just starting out in electronics repair. I have always fooled around with circuits and fixing old radios and TV's when they went down but I never really understood what I was doing. I just applied some common sense with my multimeter along with some things I picked up from a book or the internet and some how got things working again (most of the time). Well anyway I'd like to start understanding what I am doing and getting better at it, hopefully moving on to some more advanced things and going from there. I've been watching some videos and I recently purchased some equipment and combined in with what I already had. I now have an EX330 Multimeter, a solder sucker, variable temp solder gun, good solder and wick, different arrangements of resistors, capacitors, etc, a bread board, heat shrink, etc. I wanted to start out with the basics and then work my way up. I'm really interested in older tech like 60's-70's TV's and such with older displays. Although, I don't know where to start. Where could I find some older stuff to learn on? None of my current things are broken to fix! I've looked on Ebay and by the time I have it shipped to my house, it comes out to way more than it should due to the weight. Basically the question is, where can I pick up some old stuff to fix and possibly sell in the future to pay for my tools, etc? Am I on the right track of starting small with a multimeter? Thanks a lot and I appreciate the responses.

author: timb
author_rank: Super Contributor
timestamp: October 08, 2016, 09:59:29 pm
content: Craigslist, Estate Sales, Garage Sales and Thrift (Second Hand) Stores is where I'd start.

author: bitseeker
author_rank: Super Contributor
timestamp: October 08, 2016, 11:04:38 pm
content: For minimizing search and travel time for vintage consumer electronics to fix/practice on, ask people you know and definitely check out garage sales in your neighborhood. If you have a periodic neighborhood cleanup program when everyone gets rid of their old stuff, have a look around.In addition to second-hand/Goodwill stores, check to see if you have recyclers in your area that sell the things people drop off to them.Craigslist can have good deals or it can be as high or higher than eBay, depending on your area. So, be sure to do your homework before buying.
Starting up RN4020 BLE - Page 1
Forum section: electronics / beginners

author: ProAce
author_rank: Contributor
timestamp: March 24, 2016, 08:26:04 am
content: I've bought the RN4020 bluetooth module and I want to connect it to rs485. So I am designing a simple board with 4 pins (Vcc, GND, A+, B-). I'm a newbie so forgive me for my lack of knowledge. Using the user guide (http://ww1.microchip.com/downloads/en/DeviceDoc/70005191B.pdf) I came up with schematic which I included in this post. While testing I have CMD pin high. The module doesn't response. I cannot even see it via bluetooth. If you've got any experience with the module or any idea why it doesn't work please tell. I'm also open to advice and critique. (edit) On serial I've set baud to 115200 and I'm getting ERR messages.

author: Alex Trofimov
author_rank: Contributor
timestamp: March 24, 2016, 10:41:27 am
content: Sorry, can tell nothing about bluetooth, not into this sort of application at all.About RS-485, you must use flow control with half-duplex RS-485. Connect DE and RE together and drive them to "1" for transmitting and to "0" for receiving. Also, MAX13487 has automatic flow control. Maybe there're some other RS-485 drivers with this feature, but I'm not sure.Please consider, that if you use long (I'd say about more than some tenths of centimetres for LTC1480) cable for RS-485, you must have proper termination. In most cases it's sufficient to have a resistor connected from A to B on both ends of the cable. The value of it must equal to characteristic impedance of the cable. Most datacom cables have 120 Ohm characteristic impedance.

author: ProAce
author_rank: Contributor
timestamp: March 24, 2016, 10:57:25 am
content: Thank you for the feedback. I have used rs485 before and I ussually do as you say when I use them with with PIC using the transmit pin. I have already made a mini board with HC-06 module to rs485. I connected the pins as I did here and it worked. I guess I'm enabling recieve and transmit simultaneously. It wasn't reliable though (low range, noise...). I will try to connect them together anyway just in case although I think if I'm getting "ERR" messages the communication is working.

author: ProAce
author_rank: Contributor
timestamp: March 24, 2016, 11:17:35 am
content: Update: As I connect the module (CMD high, WAKE_SW high, WAKE_HW high) it sends CMD<CR><LF> and after that it keeps sending ERR<CR><LF> in a very fast loop so I'm unable to use serial.
startup option in simulations: LTSpice and ngspice - Page 1
Forum section: electronics / beginners

author: Bigman
author_rank: Regular Contributor
timestamp: April 12, 2015, 07:13:28 am
content: Hi,let's have a very basic circuit like this: GND|---- voltage source ----- capacitor ---- resistor -----|GNDWhen I run a simulation with LTSpice, the voltage at the capacity is NOT building up like an exponential function. The reasoning I found by googeling: as long as the "startup" option is not set, the simulation would assume the full voltage is instantly available at the connected elements.Since I am a Linux guy, I do my simulations with ngspice which doesn't have such a "startup" option (e.g. there is no ".tran 0.1m 10m [...] startup").As an interim solution, I add to my voltage source a PWL instruction like this one: "V1 node1 node2 PWL(0 0 1e-9 3.6)"I am wondering: how would professional people solve this issue? I also just took 1 nanosecond by random. What duration would be really meaningful?

author: PSR B1257
author_rank: Frequent Contributor
timestamp: April 12, 2015, 07:29:02 am
content: QuoteNot quite. LTSpice assumes a stady state and therefor a loaded capasitor.You have to apply a stepfunction do the RC-network, in order to see the stepresponse.Click on the voltage source, choose ADVANCED and then PULSE.

author: mrflibble
author_rank: Super Contributor
timestamp: April 12, 2015, 08:32:14 am
content: Quote from: Bigman on April 12, 2015, 07:13:28 amAlternatively, you could just useLTspice with wine. That has worked just fine for many versions now...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 12, 2015, 09:47:20 am
content: Most SPICEs have options for DC startup conditions; I don't know offhand what NGSpice does.Worst case, you can indeed use a VPULSE to do the same thing with a small delay.Tim

author: Anand
author_rank: Contributor
timestamp: April 12, 2015, 09:54:16 am
content: Another option is to use initial conditions for the cap (inital voltage would be Vcap = 0V), but that would be a waste for circuits with a lot of caps.
State diagrams - Page 1
Forum section: electronics / beginners

author: djsb
author_rank: Super Contributor
timestamp: March 14, 2010, 04:26:12 pm
content: Hi,Does anyone know where I can get a CLEAR explanation of state diagrams and finite state machines? It is one of the areas that I have never been able to grasp. It would be nice if there where some easy to understand examples that I can work through. Maybe someone could point me to a chapter in a book?Thanks.David.

author: rossmoffett
author_rank: Regular Contributor
timestamp: March 14, 2010, 06:25:31 pm
content: Well.. I'll do the best I can. I never had any written explanation of how to do it, we just had to learn for my digital logic class.A state machine has a statement inside of it which is executed, and then it has paths leaving it with conditional statements (they lead to the next state machine). If the statement is true, then that path is taken. If not, then you're stuck.That's it. You can make huge complicated state diagrams with that simple principle. I made an arcade game, dance dance revolution, using state machines. Sometimes the code blocks they executed were discrete logic or VHDL.The point of a state machine is to create an orderly sequence of events, because with unclocked discrete logic, unexpected events are much more likely to occur.

author: fsleeman
author_rank: Regular Contributor
timestamp: March 15, 2010, 01:29:01 pm
content: Procedural programming languages like C are basically glorified state machines. If you replaced all of decision making keywords (for, while, switch, etc.) with if statements you would have something that would look like a state machine. The finite part implies that there is only a finite number of states and that the entire behavior of the system can be determined and therefore validated. Writing the states and their transitions like a flow chart can make it easier to locate undefined states. If you have every written source code I am sure you know how easy it is to miss a condition in a if statement of a while loop. This kind of state validation is especially important for control systems because undefined states can cause really nasty problems.
State of charge of Lithium Ion batteries at low discharge current. - Page 1
Forum section: electronics / beginners

author: joseph.anand
author_rank: Regular Contributor
timestamp: September 11, 2012, 09:15:20 am
content: Hi I am working on a project that is powered from a 3cell (11.1v, 2000mAh) lithium ion battery pack. The max discharge current is less than 80mA, and typically around 50mA. I am unsure of the voltage levels to use for measuring the state of charge at this discharge rate. I have seen a 3.5-3.58v for 0% at 1C discharge rate. The only option for me seems to be to use a constant current source and discharge the battery to get a measurement of the discharge profile.ps: My ADC has a usable resolution of 8bits which is not very good.

author: samgab
author_rank: Frequent Contributor
timestamp: September 11, 2012, 09:33:43 am
content: They'd be fully discharged at about 2.7V per cell, so 8.1V. But for longevity of the cells, it's better not to discharge below 3V per cell, so 9V.There isn't much capacity left once you get to 3V per cell anyway, so you aren't losing much in the way of cycle duration.

author: IanB
author_rank: Super Contributor
timestamp: September 12, 2012, 01:25:38 am
content: In most cases, brand name lithium ion batteries (Panasonic, Sanyo, Sony, etc) have data sheets from the manufacturer that give actual discharge curves at different rates. All though discharge voltages are generally similar and can be estimated as samgab indicated, they do vary a bit and there is no substitute for actual manufacturer data.
Static build up issue with audio equipment - Page 1
Forum section: electronics / beginners

author: Synoptic
author_rank: Contributor
timestamp: September 28, 2015, 07:39:13 pm
content: Following my previous thread :https://www.eevblog.com/forum/beginners/new-here-and-have-a-question-regarding-an-audio-recording-issue-in-smal-aircraft/.Afer about 45 mins to an hour of usage, there will be static in the feedback audio when I transmit. However, there is no static getting emitted, so the problem is really within the intercom feedback.I was wondering if my ghetto attenuator which works fantastic at reducing the noise I was chasing, could be the culprit of a static build up ? I noticed that when I unplug it and plug it back, the static disappear for a while.What can I do to prevent static build up ?
Static circuit analysis - Page 1
Forum section: electronics / beginners

author: username
author_rank: Newbie
timestamp: February 13, 2017, 04:12:17 pm
content: I need help with the following question:For the circuit inattach 1, determine the logic function and minimum resistance value of the resistorRcminsuch that the output transistor is in saturation state when it is on.If the output transistor is charged with capacitorCp=220nF, determine the fall and rise time of the output voltage.Given data:?min=50, ?=100, Vcc=5V, Ubet=0.5V, Ubes=0.7V, Ube=Ud=0.6V, Uces=0.2V.Note: This is not homework, I am practicing for exam.Attempt:We consider the static analysis of a circuit (low and high logic level).Note: I assumed that diodes are idealized (when it is forward biased the voltage is 0.6V, and when it is reverse biased, it is an open branch).1. Low logic level (Vin=0V)We don't consider this case because we can never haveVin=0V.Is this correct?2. High logic level (Vin=Vcc=5V)We conclude that at least one input diode is forward biased.Fourth diode (that is connected to emitter of input voltage) is reverse biased.Output transistor is on. We need to check if it is in saturation state.The condition isIcs>Ib/?min. We can findIbasIb=Ubes/5k=0.14mAandIcsasIcs=Uces/Rcmin. This gives thatRcmin>200/7 ?.Is this correct?Where to connect capacitorCpand how to find fall and rise time ofVout?What is the value ofVoutin this case?How to determine the logic function of this circuit?

author: sentry7
author_rank: Regular Contributor
timestamp: February 13, 2017, 04:36:38 pm
content: Well to determine the logic function, try constructing a truth table. Toggle va, vb, and vc HI and LO and for each case, look at the equivalent circuit and find the voltage (HI or LO) at the output.
Static diagram tool - multiple tasks in code - freertos - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: October 07, 2025, 01:31:09 am
content: 1.started usinng freerots, have multiple tasks like ble server, wifi, pwm, adc, nvs, etc2. Now as code increases, new tasks keep on adding, is there any good static digarm tool which can make a diagram of all tasks & give a glance how all tasks are managed, so that it can give idea at glance3. deepseek suggested plantuml, i tried as well, it is generating good digarms4. Just wanted to know what static tool is mostly used in industry & any good suggestions ?

author: tggzzz
author_rank: Super Contributor
timestamp: October 07, 2025, 08:31:53 am
content: Quote from: Vindhyachal.takniki on October 07, 2025, 01:31:09 am"how all tasks are managed" is both too vague and too complex. There are many ways of using tasks, and there is no diagram technique that will show them all.If you keep on "adding tasks", I am completely unsurprised that becomes a problem. It sounds like there is no planning, and the interactions will become incomprehensible.Fundamentally you need anarchitectureof how the system will operate, in terms of inputs and outputs, computation, dependency, latency.Afterthose are defined, you can decide on how those will be mapped to tasks, interrupts, messages, processing.Strongly consider an architecture based oneventsandactionsdefined in terms ofFSMs. Events are messages between tasks (sometimes generated by an interrupt), and the actions are computations performed in tasks. Debugging and logging (even in deployed systems) then becomes trivial: just monitor the events.Use the UML statecharts and swimlines charts to design the interactions.Alternatively, if you expect a tool toextractwhatcouldhappen from the entrails of your code.... good luck with that!

author: thephil
author_rank: Regular Contributor
timestamp: October 07, 2025, 08:34:32 am
content: I don't know what is most popular in industry. Personally, I like Plant-UML. I know several people who prefer mermaidhttps://mermaid.js.org/.
STC12C5A60S2 flashing - Page 1
Forum section: electronics / beginners

author: kazoe
author_rank: Newbie
timestamp: April 01, 2023, 07:08:34 pm
content: Hi, Im a beginner in electronics and i found this old mcu that i got from an old led cube from aliexpress. I wanted to reflash it for other purposes, but it does not work... When I click on check MCU, it checks the target MCU, but does nothing. Any advice? Edit: on the power rail is a 10nf and 100pf and at the crystal 2x 47pf.

author: WattsThat
author_rank: Frequent Contributor
timestamp: April 01, 2023, 07:32:57 pm
content: Not familiar with the 12C series but I can suggest two things.1. RST line needs a 10uf cap in addition to the 10k pull up resistor. Refer to page 383 of the datasheet.http://www.stcmicro.com/datasheet/STC12C5A60S2-en.pdf2. Be sure to download an empty program into the Arduino to use the usb<->serial converter as a standalone converter. If the Arduino program has any debug.print statements, there will be activity on the tx pins, confusing the processor.PS: note the datasheet says <47 pf for the loading caps. 22 pf would probably be a good choice.

author: wraper
author_rank: Unknown
timestamp: April 01, 2023, 07:38:58 pm
content: 47pF capacitance on crystal is a lot. Generally you need about half of that and datasheet shows <47pf, not 47pF.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 02, 2023, 08:05:54 am
content: normally 22pf to 33pf is the go to ??
STC90C516RD+ Microcontoller Vcc - Page 1
Forum section: electronics / beginners

author: PhelarNord
author_rank: Newbie
timestamp: December 21, 2019, 08:12:43 pm
content: Hi!I´m tryin to repair a disco laser that is controlled by a STC90C516RD+ microprocessor. I´ve started to check the voltage around the circuit.(No schematic over the laser)There is one thing i dont really understand, maybe a noob thing.... I´ve checked the data sheet and this chip wants 3-5v on vcc pin 40 and its ground on pin 20.In this particular circuit its grounded on pin 40 and with reference to that it has -5v on pin 20...the ground pin. There is a 7905 up stream that feeds pin 20.Can someone explain this?http://www.stcmcu.com/datasheet/stc/STC-AD-PDF/STC90C58RD+-english.pdf

author: amyk
author_rank: Super Contributor
timestamp: December 21, 2019, 09:19:18 pm
content: Voltage is relative... all the IC needs is for Vcc to be above ground by its supply voltage, which is what that circuit provides. They probably did it that way so that the outputs would be at the right levels to interface with the rest of the circuit.

author: PhelarNord
author_rank: Newbie
timestamp: December 21, 2019, 11:14:16 pm
content: Thanks a lot!! Thats clear as chrystal!Cheers
Steady State Power Limit Calculation - Page 1
Forum section: electronics / beginners

author: nikhil142
author_rank: Newbie
timestamp: March 12, 2018, 07:43:54 pm
content: I think the solution is wrong. The right method to do this would be theta=90 and not del=90. Please help me this problem.Also is there any software with which I can plot power developed by generator ie (E x I*) vs rotor angle ie (del).
Step down converter for a battery build  - Page 1
Forum section: electronics / beginners

author: minim
author_rank: Contributor
timestamp: October 08, 2018, 06:51:28 pm
content: I got a Maxabeam flashlight that accepts 10-13.5Volts input. It's a short arc 85W bulb in it. Since this match bad up with the 18650 batteries I was going to build a pack from I was looking at a stepdown converter from Pololu (D24V150F12). It's rated at 15A max (32A peak) and my flashlight is pulling 8.5A@12V and 20.5+-3.2A at powerup. The light has a flash function so I would prefer something that could supply 23A stead since it will most likely be pulling 23A at every flash when that is used. Are there any better options out there since this seems like bad efficiency?On paper the pololu module should do fine since it can provide 15A solid and 32A burst, but I find that odd since most of the modules I find on ebay even at 5-10A rating has huge heatsinks on it and this pololu has nothing.The battery will be built from 18650 cells and it will be around 150-200Wh and I will use a BMS system.Link to the pololu module:https://www.pololu.com/product/2885
Step down converter frequency (AZ34063UP-E1) 180Khz ? - Page 1
Forum section: electronics / beginners

author: tsachi
author_rank: Newbie
timestamp: February 02, 2016, 02:36:37 pm
content: Hi,I was looking on AZ34063UP-E1, and it's spec at :http://www.mouser.com/ds/2/115/AZ34063U-271663.pdfwhich stated that it's a 180Khz switching regulator, and then I stumbled on fOSC spec being between 30-45 Khz.Am I missing something ?i.e. does this switching regulator works at 180Khz ( with corresponding capacitor ), or does it work in the 30-45Khz range ?Tsachi

author: rob77
author_rank: Super Contributor
timestamp: February 02, 2016, 05:31:03 pm
content: 30-45Khz is specified for 1nF timing capacitor (more acurately VPIN5=0V, CT=1.0nF, TA=25oC) . you can use smaller capacitor for higher frequency. but considering the fact it's a standard 34063, i wouldn't go higher than that 30-45Khz.

author: tsachi
author_rank: Newbie
timestamp: February 02, 2016, 07:19:05 pm
content: Oh... I see. The frequency was calculated based on the capacitor value in the example.thanks for the clarifications !Tsachi
Step Down Converter power consumption - Page 1
Forum section: electronics / beginners

author: Mark IV
author_rank: Contributor
timestamp: February 02, 2016, 08:28:09 pm
content: Hi All!How can i calculate the power consumption of a buck converter like this one:http://www.ti.com/lit/ds/slvsac3d/slvsac3d.pdf?Do i need only to consider the quiescent current or I need to take care of other params?

author: mikerj
author_rank: Super Contributor
timestamp: February 02, 2016, 09:10:52 pm
content: The power into the regulator will depend on the power into the load and the efficiency of the device. e.g. if it was only 50% efficient, you'd have to put twice as much power in as you got out.

author: Mark IV
author_rank: Contributor
timestamp: February 03, 2016, 09:23:19 am
content: So, an example:I use 2xAA batterries with 2500 mAh and the buck converter with 50% efficiency and 100 mA quiescent current. If the load takes 2400 mA, the battery life should be 0.5 hour, correct?

author: mikerj
author_rank: Super Contributor
timestamp: February 03, 2016, 10:38:08 am
content: Quote from: Mark IV on February 03, 2016, 09:23:19 amA switching regulator is a constant power device i.e. output power = input power * efficiency. You are talking in terms of only current, so without knowing the voltages of the supply and the load there isn't enough information to answer your question.The quiescent current of a switching regulator is taken into account in the efficiency calculations, which is why efficiency falls as the load current falls to low values.e.g. if your batteries are wired in series and give 3v, and your load voltage is 2v and the load draws 100mALoad power = 2*0.1 = 0.2 WattsSource power = 0.2/50% (i.e. 50% efficiency at the given load current) = 0.4 WattsSource current = 0.4/3 = 0.133 AmpsBattery life = 2500/133 = 18.8 hours.In practice battery life isn't as easy as that to calculate, since the capacity of the battery varies according to how much current to draw from it, and also the voltage at which your system stop working.

author: Mark IV
author_rank: Contributor
timestamp: February 03, 2016, 11:13:18 am
content: Thanks!Yes, and also the voltage fo the batteries goes down over time...It seems a good problem to solve.
Step down converter power goes off after a second or two after switch on. - Page 1
Forum section: electronics / beginners

author: mmbjm
author_rank: Newbie
timestamp: June 04, 2024, 10:28:31 pm
content: Hi, I'm after a little advice if possible.I have just purchased a Bronson++ HE-D 4000 step down converter. I bought it off Ebay and was advertised as new.It looks brand new in a sealed box.The problem is, I plugged it in and switched it on , the green power light stayed on for a second or two then switched off. It will do this everything I switch it on.The advice I'm asking is if anyone can tell me could this be an cheap fix or do I learn from my mistake and bin it.I bought it from Ebay and the it says no returns.Thank you for any advice.PS, I don't know much about electronics.

author: themadhippy
author_rank: Super Contributor
timestamp: June 04, 2024, 10:48:55 pm
content: Quotemeans nothing ,open a case with ebay pointing out the goods are faulty.

author: mmbjm
author_rank: Newbie
timestamp: June 04, 2024, 10:53:11 pm
content: Thank you for the reply and I think I'll take your your advice.

author: wraper
author_rank: Unknown
timestamp: June 04, 2024, 10:57:15 pm
content: Unless something changed lately, if "item not as described" is selected as a reason, seller cannot do anything about it other than accept the return or forfeit the item and lose all the money anyway.

author: mmbjm
author_rank: Newbie
timestamp: June 04, 2024, 11:00:14 pm
content: Thank you
Step down DC voltage before switching regulator - Page 1
Forum section: electronics / beginners

author: desertgreg
author_rank: Contributor
timestamp: February 28, 2019, 09:59:00 pm
content: I have a couple switching regulator circuits I like to use which support (say for example) a range of around 17V down to close to 5V for a 5V output. I want to use one of these on a battery powered robot which has a VIn of around 32V. Rather than use a different switching regulator I was wondering if there is a simple "reasonable / ok" method for stepping down from 30 to within range of the regulator. I should probably just find another regulator but I thought there might be other solutions that I'm not aware of since the input stage wouldn't need accurate regulation, just something like "cut the voltage in half without wasting power".

author: kjr18
author_rank: Regular Contributor
timestamp: March 01, 2019, 05:48:31 am
content: That's a lot of batteriesThere is no way to lower the voltage without wasting power, even the best optimized switching regulators waste a bit of it. You have two ways to solve this, either use a pre-regulator, or use a regulator with wider voltage input. But beware of efficiency, even if your regulator says it has high efficiency, it won't be when regulating with that voltage difference.I don't really know about your robot, but for example if you need not much power, you could try tapping of from fewer batteries, but only when this is possible and won't discharge these battteries too much. It all depends on what you need.

author: josip
author_rank: Regular Contributor
timestamp: March 01, 2019, 10:24:07 am
content: Quote from: desertgreg on February 28, 2019, 09:59:00 pmFor powering microcontrollers from higher voltage I am using RT6208. In my case it is 25V down to 3.3V with 100mA current. If this current is not enough in your case, I guess that you can find similar device with higher current possibility.
Step-down switching regulator voltage drop handling - Page 1
Forum section: electronics / beginners

author: gary_01
author_rank: Newbie
timestamp: October 18, 2016, 07:46:10 pm
content: I'm working on a raspberry pi "hat" and as part of that I want to power the pi from the hat. The project needs both a 12v (for motors) and 5v supply (for PI/ICs). Attached is a schematic using the LM2576 (non adjustable 5V out) based on the datasheet's example 12v to 5v step down circuit.My question is with regards to the D3 diode I've added. As the Raspberry Pi could be powered up at the same time as power is applied to P1, the "hat" spec suggests a protection diode be added. Given that the expected avg current draw is ~1A but there are cases where closer to 2.5A could be drawn for a short time or the entire system could be idling down closer to 0.5A. That diode I think will result in a voltage drop of ~0.2-0.5V depending on load so a final output of 4.8 to 4.5V.I could switch to the adjustable version of the LM2576 and select R1 and R2 such that the voltage output is a little higher to keep the final output within the 5.2 to 4.9V range depending on load but I'm wondering if there's a better way to handle this?

author: DutchGert
author_rank: Frequent Contributor
timestamp: October 19, 2016, 12:24:41 pm
content: Connect the feedback (pin 4) after your diode or so to say 'at the point of load'

author: smoothVTer
author_rank: Regular Contributor
timestamp: October 20, 2016, 04:40:28 pm
content: If you use a low Rds spec'd MOSFET in the usual hat spec "ideal diode" circuit, you would have a minimal voltage drop while providing protection from reverse voltage conditions as well protection against back feeding alternate supplies:https://learn.sparkfun.com/tutorials/pi-wedge-b-hookup-guide

author: gary_01
author_rank: Newbie
timestamp: October 20, 2016, 04:52:51 pm
content: Thanks for the replies. I'll take a look at the "ideal" diode alternative.
step of the trigger level - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: March 30, 2018, 06:50:49 pm
content: Hello, I have a rigol ds1054z, the level of trigger decelerates from 20 to 20 when turning the knob, there is some way to configure it from 10 to 10, as well as the vertical that pressing the knob is finer step.
Step-Up Transformer trouble. 110v into 220v - Page 1
Forum section: electronics / beginners

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 29, 2014, 06:32:20 am
content: Hey everyone. I have a step up transformer i recently bought, but to my surprise the Neutral of the Input plug is a dead SHORT to the LINE of the 220v output. And the LINE of the input of also 6 OHMS to the Neutral of the 220v output. The transformer is working fine and i have taken it apart to check for circuitry, there is none. I always thought that the step up is isolated but it looks like now it is not isolated at all, can someone please explain to me how that works? I have attached a screenshot of a crude diagram i drew with Eagle.

author: Simon
author_rank: Unknown
timestamp: September 29, 2014, 07:09:03 am
content: can you post a picture. They may have not wanted to have the output floating, you can connect the two "neutrals" together, it may even be that you have some sort of autotransformer.

author: Andy Watson
author_rank: Super Contributor
timestamp: September 29, 2014, 07:38:49 am
content: It will be an autotransformer. Basically, it takes one 110V winding and stacks it on top of another 110V winding. This saves materials (and money) by utilising one of the 110V windings twice. It only needs three terminals - I guess it is manufactured with four terminals for convenience of wiring. It's slightly surprising that the neutral in is labelled as the line out, but as you say, it works.Alternatively, think of it as one 220V winding with a 110V tap.

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 29, 2014, 07:55:44 am
content: Ahh ok, its getting late here ill post of pictures tomorrow.
stepdown buck converter supporting 48V input  - Page 1
Forum section: electronics / beginners

author: Swake
author_rank: Frequent Contributor
timestamp: November 07, 2014, 10:43:06 am
content: I'm looking for a stepdown buck convertor supporting an input of at least 48v DC and a single output voltage.Something similar to an LM2596 would be ideal. Or similar to this ready made convertor:http://www.ebay.com/itm/DC-Adjustable-Buck-Converter-Voltage-Regulator-Power-Supply-4-40V-to-1-5-35V-/390963356728?pt=LH_DefaultDomain_0&hash=item5b073b6438So fairly low amp (this is what I currently need: 3.0V; 3.3V; 5V; (200mA) and 2A at 12V)Who can help me in the right direction?

author: planet12
author_rank: Regular Contributor
timestamp: November 07, 2014, 11:33:37 pm
content: Take a look at the LM5085 from TI: up to 75V input, drives external PFET directly. Only thing that you might not like is the available package options.

author: Psi
author_rank: Super Contributor
timestamp: November 07, 2014, 11:57:33 pm
content: http://www.digikey.com/product-detail/en/ULT-12%2F2.5-D48N-C/811-2330-ND/2919826US$2436-75V input12V @ 2.5A output.91% efficientSlap some linear regs on the output to get your 3.0V, 3.3V, 5V and you're done.If you seriously need 12V@2A plus 3V@200mA plus 3.3V@200mA plus 5V@200mA ... ie 12V @ 2.6A, you might be pushing it a bit far though.Adding a cheap switchmode 12V -> 5V converter would lower the 12V current and bring you back within limits though.

author: sleemanj
author_rank: Super Contributor
timestamp: November 08, 2014, 03:09:02 am
content: Quote from: Swake on November 07, 2014, 10:43:06 amThere are HV versions of the 2596 boards that do to 60v. But be careful, fakes (standard voltage ones remarked as HV) are around.

author: Swake
author_rank: Frequent Contributor
timestamp: November 12, 2014, 02:05:23 pm
content: Thank you for pointing me towards the LM2596HV. Although I could not find a specific 'HV' datasheet yet. It looks to be the right solution. As I need about 60 or so converters, price is important as well. Will be careful avoiding fake versions. A test as in the video seems to be the right thing to do.What i found so fat to identify a 'good' board supporting 60V input:- Look carefully at the pics if it is indeed a LM2596HV chip. If it is not visible, do not buy.- The input cap should be 63V or better.- 2 'big' diodes near the input cap- The board is preferably red (not that this does anything to its voltage support)- If cost is anything less than 4$ it is suspicious.- 50V or 55V continuously is quoted in the descriptionQuote from: Psi on November 07, 2014, 11:57:33 pmSorry for the confusion, one of them at a time is more than enough. In a rare case I might need 5v and a couple of mA at 3v3 but than is easy enough to solve.

author: jb79
author_rank: Contributor
timestamp: November 13, 2014, 11:47:56 pm
content: Quote from: Swake on November 12, 2014, 02:05:23 pmThere is no extra datasheet for the HV version, both versions are in one datasheet, because they behave similar.Whenever there is a difference the values are shown separately.http://www.ti.com/lit/ds/symlink/lm2576hv.pdf
Stepper controller board - is ground plane needed for motor out? - Page 1
Forum section: electronics / beginners

author: Bob Sava
author_rank: Regular Contributor
timestamp: March 07, 2018, 05:05:48 pm
content: I'm designing a stepper controller PCB.PCB will be two layers and I have an option to route traces to the motor coil (output from the driver, OA+ OA-) side by side on the same side (layer1) over ground-plane (layer2). Another option I'm considering is one trace (OA+) on layer1 over trace (OA-) on layer2 (in parallel).Advantage of running one trace 'on top' the other would be that I can make the traces wider which is and plus since board will be small. I am thinking that the only advantage of running stepper motor traces over ground-plane would be some shielding from ground-plane - is that right? Breaking the ground-plane with motor trace will not result in ground loops, btw, because traces will be on the edge of the board.Should I worry about EMI or impedance?

author: james_s
author_rank: Super Contributor
timestamp: March 07, 2018, 05:54:17 pm
content: Without seeing your layout it's hard to say for sure, but generally speaking this shouldn't be a problem. Just keep the traces as short as is practical and avoid running sensitive signals too near, especially parallel to the motor traces.

author: Ian.M
author_rank: Super Contributor
timestamp: March 07, 2018, 06:37:55 pm
content: Minimising the loop area is good. Running the traces to the motor coils over each other on opposite sides of the board may even radiate less EMI than the alternative of same side over a groundplane. However due to TMC2100 package pinout constraints you wont be able to do that right up to the chip, and it would be inadvisable to compromise groundplane integrity round the chip.

author: Bob Sava
author_rank: Regular Contributor
timestamp: March 07, 2018, 06:50:54 pm
content: Thank you for your replies. I think I can run OA+ and AO- traces away from the IC on layer1 and switch layers for one trace at the edge of the PCB, away from the IC.EDIT: what about capacitance - could that be an issue?
Stepper driver DRV8825 gave magic smoke, what could be the reason - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 14, 2021, 06:01:17 pm
content: I setup Arduino Duo with RAMPS board on it,I configured 3, DRV8825 stepper motor drivers with pot set as required and setup X,Y & Z Axis, and they worked all good. I keep experimenting movements of X,Y & Z axis for at last one month and everything looked good.Yesterday i plugged in USB and then powered on my 12v power supply attached to RAMPS for motors, and DRV8825 on X Axis gave magic smoke, Arduino Duo, USB isolator everything gone.I'm unable to understand what could be the reason for all this, can anything could be the reason like:- While Arduino and RAMPS' power was removed I disconnected X Axis' jack and then put it back, not sure if connector was not connected properly like pins were not connected one on one ie. can below configuration may cause the damage? (though I believe jack was properly connected, just saying if)-1 xMotor -2 1- Arduino-3 2--4 3-4-- Not sure but sound like i moved the X Axis and then realized that RAMPS power was not on and while X was moving i turned on the power, looks like it did it many times before as well.I'm sure pot position was not changedWhat other things could be the reason? I ordered new USB isolator once its here i will start working on it again.

author: mawyatt
author_rank: Super Contributor
timestamp: September 14, 2021, 06:16:26 pm
content: Not sure what happened but these stepper drivers chips often fail if something is mis-wired, high current can flow due to the low motor coil resistance.The DRV8825 doesn't seem to be a good choice for precision work, Hackaday did a review of stepper drivers and the DRV8825 showed extreme non-linearity.Might want to check the review before replacing the DRV8825 with another DRV8825.Best,

author: Ian.M
author_rank: Super Contributor
timestamp: September 14, 2021, 06:59:47 pm
content: Also note that if you let the magic smoke out of any power driver chip, it isn't uncommon for it to transiently short power side Vcc to its logic level control inputs while its dying, which is probably what killed your Arduino and USB isolator.Another possibility is your PSU transiently misbehaved and lost regulation on powerup. This is very unlikely for a dedicated fixed voltage PSU but is all too common with certain brands of cheap variable voltage bench PSUs.

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 14, 2021, 09:33:38 pm
content: QuoteI'm using transformer based adjustable power supply, do you think that can issue?
Stepper driver requires thermal pad connection to GND - Page 1
Forum section: electronics / beginners

author: newtekuser
author_rank: Frequent Contributor
timestamp: November 13, 2023, 01:06:15 am
content: I'd like to interface a 12v stepper motor to a DRV8424 driver in TSSOP28 package, per the DS, the thermal pad must be tied to ground. Unfortunately my TSSOP28 to DIP adapter does not have a thermal pad:https://www.amazon.com/Chironal-TSSOP28-TSSOP20-adapter-Adapter/dp/B07G45G9TX/ref=sr_1_3?crid=3JZYZSIMG85ID&keywords=TSSOP28&qid=1699837186&s=electronics&sprefix=tssop28%2Celectronics%2C207&sr=1-3Will this driver still function without this connection, or am I just wasting time without one? Otherwise are there any TSSOP28 adapters that come with the thermal pad?https://www.ti.com/lit/ds/symlink/drv8425.pdf

author: ataradov
author_rank: Super Contributor
timestamp: November 13, 2023, 01:30:49 am
content: It would run, but it would be extremely sub-optimal. Thermal dissipation will not be as good, so you won't be able to run it at full power. Plus you won't be able to optimally place all the decoupling and charge pump capacitors.This board has universal pads that are way too long and they would interfere with the pad, so you would have to trim them on the inside. But some traces are routed on the inside, so that would be a challenge.It is probably better to get a pre-made breakout board for this IC or make your own.

author: newtekuser
author_rank: Frequent Contributor
timestamp: November 13, 2023, 03:41:54 am
content: Quote from: ataradov on November 13, 2023, 01:30:49 amThank you! I just need to do a proof of concept on a breadboard to prove I can work with the motor, after which I'll make it proper on a PCB.Speaking of which, per the DS layout design guidelines, the decoupling caps need to be placed so close to the pads that I think my 1206 won't do and have to go smaller in size.

author: ataradov
author_rank: Super Contributor
timestamp: November 13, 2023, 03:50:04 am
content: You can try with 1206, but it would look strange. 0805 is probably the biggest I would use.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 13, 2023, 08:40:13 am
content: For one-off, you could dead-bug the chip and solder parts to it using tiny air wires, but with such package this would be colossal PITA requiring stable hand, small iron tip and lot of patience. A good exercise, but a better idea is indeed to buy a pre-made module with this chip.

author: langwadt
author_rank: Super Contributor
timestamp: November 13, 2023, 10:43:50 am
content: Quote from: Siwastaja on November 13, 2023, 08:40:13 amupside down and bend the legs would probably work on that breakout board

author: Siwastaja
author_rank: Super Contributor
timestamp: November 13, 2023, 11:09:44 am
content: Quote from: langwadt on November 13, 2023, 10:43:50 amOh yes, for the TSSOP version which actually has legs this is probably the best option by far. I have done bent-legs upside-down stuff a lot.
Stepper Motor Control – Arduino For Beginners - Page 1
Forum section: electronics / beginners

author: mahendaran R
author_rank: Newbie
timestamp: November 22, 2014, 07:33:46 am
content: I have done a program for arduino to rotate stepper motor in clockwise and anticlockwise….in that stepper motor was initially vibrating…..i have an doubt …whether I done a mistake in my program or circuit….http://www.ingenstech.com/20-stepper-motor-control-arduino-beginners/

author: rob77
author_rank: Super Contributor
timestamp: November 22, 2014, 12:09:37 pm
content: if a stepper is just vibrating instead of turning, then either you have swapped coils or the control is wrong

author: Rerouter
author_rank: Super Contributor
timestamp: November 22, 2014, 08:46:55 pm
content: In there example they are using a driver IC to buffer the signals from the arduino, are you using a chip like this, or trying to directly drive from the arduino?to reverse direction on most 6 wire steppers, you reverse the 2 outer wires for one coil, vibrating could be one wire from each coil is flipped

author: mahendaran R
author_rank: Newbie
timestamp: November 24, 2014, 05:39:13 am
content: thanks for the suggestions will see to it ...

author: Kappes Buur
author_rank: Regular Contributor
timestamp: November 24, 2014, 05:47:22 am
content: With a board likethis, it is really easy to drive a stepper motor.