hybridfree/eevblog-posts huggingface dataset:
ST Time of flight distance sensor and cone angle  - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: January 11, 2017, 09:26:47 am
content: Has anyone had any luck in narrowing the acceptance angle of a ST time of flight distance sensor?I bought a ST VL53L0X sensor which works well, but the emitter and receiver aren't focused, they act like point sources/receivers.http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/b2/1e/33/77/c6/92/47/6b/DM00279086/files/DM00279086.pdf/jcr:content/translations/en.DM00279086.pdfThe diagram on page 30 show 25 deg and 30 degrees respectively.Normal lenses appear to be unsuitable as you get light leaking from the emitter to the receiver.http://www.st.com/resource/en/application_note/dm00326504.pdfEven finding a protective window is a challenge, currently I'm using some kapton tape stuck directly onto the package.

author: voltsandjolts
author_rank: Unknown
timestamp: January 11, 2017, 09:55:52 am
content: Never done beam shaping but have used a flat glass window in front of a VL6180X which worked. The sensor was placed against the glass so reflection path is short, maybe ignores reflections as min sense distance is around 10mm. I also used reduced output power - maybe that would reduced your reflection issue. Good luck.

author: Lytic
author_rank: Newbie
timestamp: May 10, 2017, 10:01:43 am
content: If you separate the two lenses totally all the way up, like putting one in each tube and ensure there is no point where the emitter and receiver are connected, you can focus the beam and get the signal strength increased many times. But be aware of ambient light.An incandescent light or halogen light in the optic angle, causes the error "No Target", even at very few lux.
Stabilizing Cap Values for Split Rail Linear PSU... - Page 1
Forum section: electronics / beginners

author: Shredhead
author_rank: Regular Contributor
timestamp: September 24, 2014, 02:28:16 am
content: I have been making these power supplies using the schematic here that is hand drawn. Someone told be that these chips will be more stable using 10uF electro's on the in and outs instead of the ceramics. They also mentioned that the anti-parallel diodes might help with turn off pops (for audio).See Datasheets' recommendation. He was absolutely right when I read there on the L79's print talking about if you use electro's, increase the value. The L78 says no such thing.I have proposed a new design that only uses 10uF's all around now (see pic). Which of these designs will be the most stable and most quiet? I don't have an O-scope to measure with.

author: VK5RC
author_rank: Unknown
timestamp: September 24, 2014, 04:55:27 am
content: A bigger capacitor esp Electrolytics also tend to have a higher esr and equivalent series inductance, this can result in some 'ringing' of the voltage upon switching on.

author: Shredhead
author_rank: Regular Contributor
timestamp: September 24, 2014, 06:00:46 am
content: Quote from: VK5RC on September 24, 2014, 04:55:27 amIs 10uF too large an ESR? Will the ringing stop after a period of time or does it result in high frequency oscillation?

author: Simon
author_rank: Unknown
timestamp: September 24, 2014, 06:39:55 am
content: 79xx regulators are not as stable as the 78xx's so tend to oscillate more easily hence the bigger cap requirement. The old adage has been 100uF with 100nF, I'd still use the 100nF, the electrolytic can be anything going up from 10uF depends on how fast the input voltage changes and how fast the load requirements change on the output. If you ever do need a large capacitance then putting some in parallel is better than one large ones as smaller ones have less ESR and putting them in parallel makes that ESR lower due to the resistances in the capacitors being in parallel.

author: VK5RC
author_rank: Unknown
timestamp: September 24, 2014, 11:48:17 am
content: Agree with Simon, if RF involved add 100pF as well!, I've not had feedback oscillation with the LM78xx series but one (dodgy) power supply I had upon switch on had quite a nasty spike in voltage, adding an electrolytic made it mostly settle but the time to voltage stability was 10x longer. It all varied with load for good measure as well!One of the guys in my radio club built a low HF transmitter for fun using a voltage regulator as the final amp.

author: Shredhead
author_rank: Regular Contributor
timestamp: September 24, 2014, 02:27:24 pm
content: Quote from: Simon on September 24, 2014, 06:39:55 amOK, cool. Should the 100nF be closer to the IC's pins or the electro?

author: Simon
author_rank: Unknown
timestamp: September 24, 2014, 02:28:33 pm
content: the 100nF because they have lower esr and react faster,
Stable and reasonably accurate 5V from USB source (i.e. improved USB out)  - Page 1
Forum section: electronics / beginners

author: bolgera
author_rank: Newbie
timestamp: May 13, 2024, 02:48:50 pm
content: Hello,For my project I want to built not so expensive (~30 eur) relatively stable 5V DC signal that would take 5V from USB power (PC or wall plug). I want to solder elements on the board myself and will source parts individually online. Power requirements are approximately 5 watt.The way I understood the logic of the scheme. First, I should rise the voltage to some higher level (with something like TL431 but ranked for higher amp), let's say to 10V and then regulate it down with LDO to 5V?Could some-one advise/share an electric scheme and maybe suitable components as well? If i want to do add some noise filtering what is the best way to do it?Apologies if my question is repeating. I tried searching but have not found, so feel free to redirect me.Andrey

author: SeanB
author_rank: Super Contributor
timestamp: May 13, 2024, 02:56:04 pm
content: Boost converter to increase the voltage to say 7V, then a precision regulator to provide the 5V you need will probably be best.

author: bolgera
author_rank: Newbie
timestamp: May 13, 2024, 04:18:55 pm
content: So something like this from aliexpress DD03AJTA plus LM340 should be sufficient?

author: Bud
author_rank: Super Contributor
timestamp: May 13, 2024, 04:31:53 pm
content: I did it the other way around. Dropped the 5v USB power to 4V using an LDO linear regulator, then used a 2MHz boost converter to get voltage back to 5V. The linear regulator cleaned up low frequency noise coming from USB, and provided clean supply voltage to the boost converter. And it was easy to filter out 2MHz switching noise after the boost converter.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: May 13, 2024, 06:04:11 pm
content: Something likethis DC-DC convertermight be just what you need.CheersAlex

author: BennoG
author_rank: Frequent Contributor
timestamp: May 13, 2024, 06:18:05 pm
content: That is 5V 1A and add the losses so you pull about 1.2A from the USB port.USB2 is rated 0.5AUSB3 is rated 0.9AI know if you are lucky you can pull more than that from a standard USB port but if you want something to work on every device than that are the limits.USB3 PD is an option then you can negotiate 12V and buck it down to a stable 5V 1A (your buck converter should at least be capable of 1.5A to deliver reliable 1A)Benno

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 13, 2024, 06:33:28 pm
content: SEPIC.https://en.wikipedia.org/wiki/Single-ended_primary-inductor_converter
Stabo (Multifon Super 7) - Page 1
Forum section: electronics / beginners

author: Savetheday
author_rank: Regular Contributor
timestamp: April 14, 2018, 11:58:00 am
content: Hi everyoneI have an old German Stabo (Multifon Super 7) 2 walkie-talkies.Communication length between 2 of them was too short.So I decided to change all of the old electrical capacitors.Now between 2 walkie-talkies, there is no connection.I think I might be changed somehow the frequency levels each of them.Is there anyone who have datasheet or device reference guide?Thanks.
Stackable Battery Management System(BMS); Automotive grade  - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: February 22, 2017, 04:19:21 pm
content: I want to design an stackable automotive grade BMS which can go upto 800V & so. Recently I have made a 48V/100A system but it is not stackable and automotive grade.New BMS should have below features:1. Programmable OverVoltage/Undervoltage protections2. Programmable over-current/short circuit protections3. Programmable Over Temperature/under Temperature protections4. SOC/SOH calculations5. Digital communications (Smbus, Rs485)6. Stackable to high voltages.7. Charge/Discharge protections through mosfets8. Current sensing using Shunt resistors9. Passive balancingOptional features:1. Current sensing using Hall effect sensor2. Protections using Relays/Contractors3. Digitial COmmunication CAN4. Active balancing 1A or higherWhat are ASIC solutions avialble or what solution is best.I have looked through many BMS asic like:1. LT,Maxim,Fujistu & TI: All asic are for voltage/balancing only. All the programming part for reading voltage & balance commands are to be done by designer. Also SOC calculations algorithm need to be developed separately.2. NXP has IC MC33771. Its under NDA. I am in process of getting its NDA. Initially looks like it has gauge sensing also. But all the algo needs to be developed by designer. But I can say more only after reading complete datasheet.In above I dont understand when ASIC is to be used, why so much programming part has to be done by designer. It should be in IC only. Bq76PL116 was once such device. But now its NRND & it was stackable upto 16S only3. Also I found another company named "http://elithion.com/". It has IC EL01 & El02. On initial reading it looks like this is what I am looking for . They have all algos inbuilt.A) But I havent heard of this company before. Anyone knows about this company?B) They have detailed comparison of chips also:http://liionbms.com/php/bms_chips_options.php
Stacking PSUs and/or test equipment ontop of one another - Page 1
Forum section: electronics / beginners

author: 9941_0041
author_rank: Newbie
timestamp: February 22, 2025, 11:38:19 pm
content: Hi, first post on this forum, been lurking for a while. Also a beginner to electronics repair.I have an HP 6632a 20v 5a. I am wondering if it's OK for me to stack another one of these PSUs or even an oscilloscope on top of it (without a rack; think of two boxes stacked over each other)Will it cause any interference or any downsides to it's operation? I'm worried any weight on it will be detrimental to it's service life but I don't have much desk space. May sound like a silly question but I googled around and couldn't find anything on the topic.Thanks!

author: Konkedout
author_rank: Frequent Contributor
timestamp: February 22, 2025, 11:49:50 pm
content: I do not have many specifics about your bench power supply. But in general I would be most concerned about heat. I would allow at least a few cm of space between them for air circulation. Unless you are concerned about aesthetics or stability against lateral forces, I would think this should be easy to do with a couple of small pieces of wood lumber.

author: 9941_0041
author_rank: Newbie
timestamp: February 23, 2025, 01:15:09 am
content: I didn't even think about heat! My 6632a is a late 80s PSU made by Hewlett Packard, it's pretty heavy , 12 kg or so, and long ( around 17 in wide, 12 in long) . It's all aluminum construction and has a middle brace though so I think your lumber idea will work just fine. I will do exactly that.I appreciate it! Thanks!

author: Smokey
author_rank: Super Contributor
timestamp: February 23, 2025, 01:39:28 am
content: These things are designed to be loaded into 19" racks. The vents are on the sides for a reason.Hopefully this makes you feel better about stacking...
Stacking Raaco cabinets? - Page 1
Forum section: electronics / beginners

author: LektroiD
author_rank: Frequent Contributor
timestamp: June 30, 2015, 12:35:25 am
content: It appears from the indents in the corners on the top of the cabinets that they are designed to take a cabinet to sit directly on top, but when I tried this with my Raaco cabinets, they barely connect, teetering away like they are ready to drop at any moment.Is there some kind of footprint adaptor to make these cabinets slot onto the indents on top of the other cabinets to sit on top of each other, or are they designed only to sit side by side?
Standard Electronic Tools - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: August 06, 2010, 04:47:59 am
content: Quick Question, I am going into electronics and what tools do people think are required for a general electronics Technion as I have a few in networking?ex. Power Supply - 2Amps - Overload ?

author: Valhallasmith
author_rank: Contributor
timestamp: August 06, 2010, 05:43:57 am
content: Really depends on where your interests lay. Someone who is into power electronics is going to be different from embedded micros and amateur radio. But if you want a general useful stuff list:Multimeter.Small 1 or 2 amp power supply with multiple outputs. Or just batteries if you are trying to keep it cheap.Soldering station with a fine tip.Rosin solder, liquid flux, alcohol, small needle bottles, solder braid and a solder sucker.Misc small tools like screwdrivers, pliers.Couple kinds of tweezers.Variacs, oscilloscopes, LCR meters, logic analyzers are all pretty handy for specific sorts of circuits. Really it depends on how far you are going and what you are interested in working on.
Standard Mosfet VS LINEAR Mosfet - Page 1
Forum section: electronics / beginners

author: Atom
author_rank: Regular Contributor
timestamp: February 16, 2018, 07:39:51 pm
content: HIHIHIHI so i'm trying to understand why in the desing of the power supply of peter oakes is using an IRFP064...i'm testing the circuit (see other post) using as repacement an IRFP240 that i had on hand... so the question is ..is peter using it for it's heavy duty charateristics??http://www.kerrywong.com/2016/10/08/linear-mosfet-and-its-use-in-electronic-load/then i found this page about a dc load using a mosfet.. so in this case and in the case of the power supply the mosfets are used in linear mode ...like a resistor... and reading through i found something intresting..."I tested a few of the IRFP150N’s individually in linear mode and they all failed when the power dissipation reached between 45W to 60W." why standard mosfet fails ... that would be a huge limitation in a linear power supply....i'm thinking of adding a switching regulator.. but why a normal mosfet fails IXYS MOSFETS are preferred ? what does they have more than a normal mosfet?also this guy uses an IXYsS mosfet for his electronic load :http://kaktuscircuits.blogspot.it/2014/02/mightywatt-arduino-electronic-load.htmllooking forward to see all the considerations .........and i need also some advice on where i can start to study throughly the MOSFETs because right now i dont't fully understand themIRFP064https://www.vishay.com/docs/91201/91201.pdfIRFP240https://www.vishay.com/docs/91210/91210.pdf

author: jmelson
author_rank: Super Contributor
timestamp: February 16, 2018, 08:34:55 pm
content: look at the safe operating area graph. They don't even show a line for more than 10 ms duration. These FETs are built out of tens of thousands of paralleled transistors. To get better on/off performance, they sacrifice the balance between the individual transistors at partial turn-on, ie. in the linear region.If you run these transistors not designed for linear operation at modest current in the linear region, a hot spot develops, and gets WORSE as the heating continues, until the transistors in that region are permanently damaged.The transistors designed for linear use are built in such a way that even in linear mode they balance better, so a hot spot doesn't develop.Jon
Standard programming templtes c 4 embedded - Page 1
Forum section: electronics / beginners

author: rakeshm55
author_rank: Regular Contributor
timestamp: August 06, 2017, 10:11:11 am
content: Hi...Recently i have started working in embedded systems programming (tiva) in C....i am unfamilar with standards method to be followed in writing codes for embedded system...while i used to work with vhdl for fpga i used to refer to standard templates / snippets for development which inherently helped in avoiding latches...similarly are there standard templates 4 embedded c which i can refer to so that i could avoid pitfalls of a beginner....and develop efficient and bugfree codes...
STANDARD ST-61 help - Page 1
Forum section: electronics / beginners

author: drnele
author_rank: Newbie
timestamp: February 11, 2011, 01:56:10 pm
content: Hallo to everybody, I am new on this forum, I need some help choosing multimeter...I found on the market uneversal 6in1 multimeter STANDARD ST-61 with plenty of features, priced ~75 EUR:6 in 1 multifunction multimeter, including DMM, sound level meter, light meter, humidity meter, tempearture meter and Non-contact AC voltage detectorSafety design meets CAT IV 600V and CAT III 1000VInfrared probe for non-contact temperature measurementDouble molded housing4000 counts digital LCD display with back lightAuto rangingData hold and relative functionAuto power offSpecifications:Function Max Range Max. resolution Basic AccuracyLight 20,000 Lux 0.1 Lux ±5%±10d40,000 LuxSound 100dB 0.1dB ±3.5dBHumidity 95% RH 0.1% RH ±3.5% RHTemperature -20 ~ 750 °C 0.1 ° up to 400 °, 1° over 400 ° ±3%±3°C-4 ~ 1400 °F 0.1 ° up to 400 °, 1° over 400 ° ±3%±5°FNCV 50-1000VVoltage DC 600V 0.1mV ±5%±2dVoltage AC 600V 0.1mV ±1.2%±10dCurrent DC 10A 0.1uA ±1.0%±2dCurrent AC 10A 0.1uA ±1.0%±2dResistance 40M? 0.1? ±0.8%±2dcapacitance 100uF 0.01nF ±3.5%Frequency 100Mhz 0.001Hz ±1.5%Duty cycle 99.90% 0.10% ±1.2%Diode check Open voltage 2.8VDC, test current 1mAContinuity test Threshold 30?Size (H x W x D): 170mm x 79mm x 50mmWeight: 342gAs I am new to multimeters, please can somebody give me some advice, is it wise to buy something like this?I don't quite understand accuracy, but it seems to me it is not so accurate, on the market I see some multimetres with 0.5% DC voltage accuracy, and here as I see is 5%+2d (or sound 3.5db etc....)...can somebody explain me what to expect in a real life....Here is the link:http://www.wintal.com.au/upload/sellsheets/ST61-Digital-Multimeter-sellsheet.pdfThank you

author: Unknown
author_rank: Unknown
timestamp: February 11, 2011, 02:01:39 pm
content: 5% DCV accuracy is horrible, that's got to be a typo (0.5% isn't great either, pretty average for a 3.x digits meter). DCV accuracy worse than ACV and resistance is very unlikely. Apart from that, from the specs it appears this meter is heavy on features, which usually means it's light on quality. Affordable stuff either only has a limited number of features, or is crap, in my experiences. No serious DMM that I know of includes sound, light and humidity, these just sound like useless features to help it sell. No specific experiences with this meter, this is just from the specs you posted.
Standardized symbol for resistors in the USA (Solved) - Page 1
Forum section: electronics / beginners

author: Picuino
author_rank: Super Contributor
timestamp: March 18, 2025, 10:03:03 am
content: Do you know what exactly is the standard symbol for resistors in the USA?In Europe it is a rectangle and in the USA it is a zigzag line that starts to the right and ends to the left. Is it like that?

author: Picuino
author_rank: Super Contributor
timestamp: March 18, 2025, 10:05:14 am
content: This is my version, but I believe it is not entirely correct.

author: Picuino
author_rank: Super Contributor
timestamp: March 18, 2025, 10:20:18 am
content: https://www.ntchip.com/electronics-news/resistor-symbolhttps://eepower.com/resistor-guide/resistor-standards-and-codes/resistor-symbols/QuoteThis creates the problem of having to make the ANSI symbol of the resistor longer than the IEC symbol, so they will not be directly interchangeable. I have all my schematics with the IEC 60617 symbol, but I wanted to make a correct ANSI symbol of the same size. I'll see how I implement it.The doubt is solved. Thanks for reading.

author: Picuino
author_rank: Super Contributor
timestamp: March 18, 2025, 03:15:46 pm
content: Changed in KiCad library.

author: Analog Kid
author_rank: Super Contributor
timestamp: March 18, 2025, 06:53:32 pm
content: Entirely correct.I much prefer the zig-zag symbol, instead of the nameless, faceless Euro-box symbol.

author: Kharn_the_Betrayer
author_rank: Contributor
timestamp: March 18, 2025, 07:31:22 pm
content: Quote from: Analog Kid on March 18, 2025, 06:53:32 pmSeconded, though in school I'd always draw mine with two peaks up and two peaks down. It looked very neat that way

author: Analog Kid
author_rank: Super Contributor
timestamp: March 18, 2025, 07:41:10 pm
content: Here's my resistor symbol, from my "library" (CorelDraw electronics parts box):Seems like just the right number of zigs and zags to me.

author: tszaboo
author_rank: Super Contributor
timestamp: March 18, 2025, 07:49:17 pm
content: Quote from: Analog Kid on March 18, 2025, 06:53:32 pm
Standards and documents to study before graduation - Page 1
Forum section: electronics / beginners

author: crypton
author_rank: Contributor
timestamp: March 09, 2017, 03:32:21 pm
content: Hey,I once met a guy who suggested to gulp as much info from standards and other documentation as possible, that would be available through universities.I got fascinated by this idea, since most of the useful stuff are quite expensive to access while f.i working.So in contrary to the awesome sticky about freely available documents, maybe anyone of you have suggestions, what kind of standards (the ones that aren't free) you have found useful in the field of electronics and what any decent electronics engineer should study or have?

author: Benta
author_rank: Super Contributor
timestamp: March 09, 2017, 04:31:58 pm
content: At some point in your career, you'll run into the following (and they are very relevant to how you design your product).In order of probability that you'll need them, most probable first:Low Voltage DirectiveEMC DirectiveRadio Equipment Directive (supercedes R&TTE)RoHS/REACHWEEEAll of them refer to associated Harmonised Standards.I wouldn't read it all in detail, but skim through to get a feel for what is demanded from the authorities.

author: Jeroen3
author_rank: Super Contributor
timestamp: March 09, 2017, 05:04:39 pm
content: Smart guy.ISO 16750, ISO 11898, IPC 2221 come to mind.Maybe misra?Recently purchased j1939, but that is very specific.

author: ebastler
author_rank: Super Contributor
timestamp: March 10, 2017, 07:46:07 pm
content: Quote from: Benta on March 09, 2017, 04:31:58 pmNot sure whether this is actually helpful. The EU Directives are all available free of charge -- in a surprising number of languages, courtesy of the European Union. The harmonized standards (i.e. IEC/DIN etc. technical standards) are the expensive ones. And while the Directives do "refer" to them (as in "talk about the need to comply with the relevant harmonized standards"), I don't think they actually list the relevant standards.I only spot-checked the low voltage directive just now, and did not find any specific technical standards being referred to. Did I overlook these, or where would one find the list of applicable/relevant standards?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: March 11, 2017, 12:27:18 am
content: In addition to the standard knee jerk for safety and em cleanliness standards, look at standards defining interfaces particularly in your field of interest. Things like GPIB (IEC 60488-1), or WiFi (IEEE 802.11).Depending on your universities license, you may be able to download a .pdf (as long as you are not transmitting it to someone else). Unless your memory is extraordinary that is a feature well worth exploring.
Standards for numbering pins on multirow header? - Page 1
Forum section: electronics / beginners

author: MatCat
author_rank: Frequent Contributor
timestamp: January 07, 2014, 07:59:20 pm
content: Ok I want to make sure I do things according to standards as much as possible, so what is considered to be the best way to number pin headers? Let's use a 2x5 heacer as an example, so would it be:A:1 2 3 4 5 6 7 8 9 1011 12 13 14 15 16 17 18 18 20B:1 3 5 7 9 11 13 15 17 192 4 6 8 10 12 14 16 18 20Or some other configuration?

author: free_electron
author_rank: Super Contributor
timestamp: January 07, 2014, 08:04:23 pm
content: b , but not necessarily in that order...24681357

author: SeanB
author_rank: Super Contributor
timestamp: January 07, 2014, 08:07:51 pm
content: Reason it is B is that normally those connectors are used with a ribbon cable, so the numbering is then linked to counting along the ribbon from one end ( normally marked with a stripe or starting with a black wire for multicoloured ones) to the other, rather than having some scrambled numbering along the width of the cable. Thus you can split the cable mid way into 2 sections, having eg pins 1-6 on one and 7-10 on the other.

author: KJDS
author_rank: Super Contributor
timestamp: January 07, 2014, 08:58:36 pm
content: When I was young and naive, I once assumed the pin numbering on the ribbon cable coming from a D-type was 1 2 3 ...9After putting out the fire, I discovered it was 1 6 2 7 3 8 4 9Since then I've always made very very sure that I checked rather than guessed.For square pin headers, then2 4 6 81 3 5 7Is what I prefer. Just don't assume that it is, even if the connector has pin numbers on it's moulding that those match the schematic.
Standart Inverter Problem - Page 1
Forum section: electronics / beginners

author: igorbog
author_rank: Contributor
timestamp: October 30, 2011, 10:34:45 pm
content: I have created simple inverter, but when I make trans. Simulation, It shows me Low output voltage. Do you have any idea?

author: amspire
author_rank: Super Contributor
timestamp: October 30, 2011, 10:49:42 pm
content: That inverter circuit is a logic inverter - it is not intended for analog.One of two things could be happening.1. Your FET models may be for a very small geometry FET and that is the best the Pchannel FET can do into 1K, or2. The N-Channel FET is dominating and at that bias voltage, it is heavily on. A check of the drain currents would show if this is occuring.Richard

author: igorbog
author_rank: Contributor
timestamp: October 30, 2011, 10:58:27 pm
content: Thanks.Tell me please where I can in Orcad change Pmos Channel width in order to make it simitery

author: amspire
author_rank: Super Contributor
timestamp: October 30, 2011, 11:02:43 pm
content: Can you plot the n-channel drain current first?It may be very high.

author: igorbog
author_rank: Contributor
timestamp: October 30, 2011, 11:19:44 pm
content: attached

author: amspire
author_rank: Super Contributor
timestamp: October 31, 2011, 12:22:00 am
content: Wow! that is low.I suspect the mosfet models you have used are designed for internal mosfets on a LSI chip. They are probably designed for a few uA of drain current in normal operation.You should have other mosfet models.But why are you trying to use a logic circuit for inverting a sinewave?A n-channel mosfet with a 1K resistor and the gate DC biased for about half the supply volts on the drain would do a much better job as a sinewave inverter/amplifier.Richard

author: igorbog
author_rank: Contributor
timestamp: October 31, 2011, 05:20:02 am
content: you are right, but I only wanted to try this circuit. tell me please what transistors to choose and hoow do you choose them?

author: amspire
author_rank: Super Contributor
timestamp: October 31, 2011, 05:41:03 am
content: Just get libraries from the manufacturers.For example you could get the libraries for BSS84 (P Channel) and BSS123 (N channel).These are both rated at about 0.13 A drain current and about 10 ohms resistance at 5V gate-drain voltage.http://www.fairchildsemi.com/models/PSPICE/Discrete/MOSFET.htmlRichard
Standby Power in AC-AC power supplies - Page 1
Forum section: electronics / beginners

author: wardenclyffe
author_rank: Contributor
timestamp: September 05, 2013, 05:22:35 pm
content: Hey guys,I was doing some simple efficiency testing on this off the shelf AC-AC power supply the other day and I noticed that the power consumption with no-load connected (standby) was up over 5 watts! I know the current federal standard says it has to be lower than 0.5 watts and I think ENERGY STAR is around 0.3 watts. I was wondering if someone could tell me why the consumption is so high and what could be done to lower it. I cracked it open and its nothing but a transformer and some input filtering. Any ideas?

author: tszaboo
author_rank: Super Contributor
timestamp: September 05, 2013, 09:28:17 pm
content: I would recommend the GOPS.Good old power switch.

author: wardenclyffe
author_rank: Contributor
timestamp: September 05, 2013, 09:30:16 pm
content: Quote from: NANDBlog on September 05, 2013, 09:28:17 pmHaha, fair enough. Anyone got something more elegant?

author: Zero999
author_rank: Super Contributor
timestamp: September 05, 2013, 10:32:30 pm
content: AC-AC adaptors are exempt from the regulations because small mains frequency transformers are inefficient so it's impossible to achieve such a low standby power.If the device being powered just rectifies it to DC then replace the adaptor with a modern switched mode power supply based adaptor. If it needs AC then you're stuck with an inefficient mains transformer and need to turn the power off when possible.

author: edavid
author_rank: Super Contributor
timestamp: September 05, 2013, 11:45:12 pm
content: 5W sounds high even for a bad transformer. Were you measuring true power, or just VA?

author: Neilm
author_rank: Super Contributor
timestamp: September 06, 2013, 04:09:29 pm
content: If the unit was a switched type, look at how you were measuring the power. It might be that it was producing a lot of noise that was upsetting the power measurement and causing it to read high.

author: wardenclyffe
author_rank: Contributor
timestamp: September 06, 2013, 05:46:20 pm
content: Quote from: edavid on September 05, 2013, 11:45:12 pmTrue power measurement
standby power - Page 1
Forum section: electronics / beginners

author: tekman11
author_rank: Contributor
timestamp: November 03, 2014, 01:51:22 pm
content: Hi wall warts have become smaller over the years so I took one apart.the input is rectified then feed into some sort of fly back SMPS which provides a output voltage.Does anyone know of a tutorial which discuss this subject?They come in isolated and non isolated flavors, under what situation would a isolated version be used?Is input protection on the AC side (MOV or fuses) required?thanks

author: Zero999
author_rank: Super Contributor
timestamp: November 04, 2014, 09:04:00 pm
content: A wall wart should always be isolated, unless the insulation on the equipment and cabling is rated for mains voltages.Here's a link with more information on switched mode power supplies.http://www.nxp.com/documents/application_note/APPCHP2.pdf
Star Wars Dagedar R2D2 RFID Hack - Page 1
Forum section: electronics / beginners

author: btesser
author_rank: Newbie
timestamp: January 07, 2014, 08:32:11 am
content: While perusing for a snack CVS tonight I came across the 90% off christmas items section. The one item that interested me was a Star Wars Dagedar Digital Decoder,www.rebelscum.com/Droid_Display_Decoder_DaGeDar_Star_Wars.aspwhich plays different sounds when you hold different balls up to it. I figured it must be an rfid reader in there, and for the $1.99 pricetag I couldn't resist buying it to see if I could hack it and maybe use it in an arduino project.I was encouraged when I took the thing apart to SCK, SDA (I2C) and UART silkscreened on the PCB. Unfortunately whatever processor they are using is globbed all over. I took out my trusty logic sniffer but all I seemed to be able to get was what looked like a clock signal from both SCK and SDA. UART provided no data. The item won't respond to any rfid chips I have either (both frequencies). There is also a funky U shaped set of 7 pads that I'm wondering if those are possibly used to program it. Anyway, I can use whatever advice you guys are willing to share in getting something out of this thing. Here are some photos I snapped of the device:Thanks,Ben

author: Unknown
author_rank: Unknown
timestamp: January 07, 2014, 09:57:48 am
content: Looks to me like a standard development board that someone has hacked bits off of. Can't see it being too difficult to find out what it is.

author: btesser
author_rank: Newbie
timestamp: January 08, 2014, 12:33:46 am
content: More news of nothing :-/I soldered wires onto those 8 pads in the U-Shaped formation and hooked up up to my logic analyzer. I got nothing. Nothing during power on, nothing when I press the button. Nothing when I wave a RFID card near the device. I'm afraid I've hit a dead end. Any ideas? I"m very curious why there are connectors for UART I2C and a weird breakout but I get nothing on my scopes.Thanks,Ben

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 08, 2014, 12:44:43 am
content: I'd be surprised if something like this uses any standard RFID tag - more likely a proprietory, very simple system designed for absolute minimum cost of all parts. Could be a simple as LC resonance, using different frequencies for different tags

author: wilheldp
author_rank: Regular Contributor
timestamp: January 08, 2014, 12:58:23 am
content: Have you tried putting some sort of antenna hooked up to a scope/signal analyzer between the ball and the detector to try to pick up the frequency of the RFID tag?

author: amyk
author_rank: Super Contributor
timestamp: January 08, 2014, 07:45:44 am
content: The ID0-ID7 label suggests an internal databus of some sort... I bet the CPU inside is a mask ROM version. COBs are common on extra-low-cost high-volume stuff like this; buy one to decap, and one to experiment on.
Starter motor brushess - Page 1
Forum section: electronics / beginners

author: Apple
author_rank: Newbie
timestamp: April 12, 2025, 10:14:41 pm
content: Hi,Can someone explain to me how this 4 brushes DC motor works? How they are wired? I know for two regular brushes, but why are there sometimes four brushes?The picture is here.https://imgur.com/a/oJA8UhVThanks.

author: amyk
author_rank: Super Contributor
timestamp: April 13, 2025, 01:58:34 am
content: Looks like someone already answered here, with your exact same picture:https://www.physicsforums.com/threads/four-carbon-brushes-for-a-dc-motor-what-are-they-for.927521/I also recommend the old (late 19th/early 20th century) books on DC motors at archive.org - lots of still-relevant knowledge that's hard to find elsewhere.

author: David Hess
author_rank: Super Contributor
timestamp: April 13, 2025, 04:57:23 am
content: Starter motors are 4-pole instead of 2-pole to double their torque and power within the same volume. It is like having two 2-pole motors in parallel. The compromise in doing this is that they are more complicated, and since efficiency is not increased, they overheat twice as quickly so run time is more limited.

author: Apple
author_rank: Newbie
timestamp: April 13, 2025, 09:59:37 am
content: Oh, I see now. I have googled DC motor with four brushes and have copied the image.Thanks anyway.
Starter Project: Camera and Live Feed - Page 1
Forum section: electronics / beginners

author: im_a_kobe
author_rank: Newbie
timestamp: July 26, 2018, 11:55:18 pm
content: Hello folks,First of all, a disclaimer: I am an absolute beginner and I'm seeking a way to actually begin. If this is the wrong page/protocol for this, please kindly direct me to the right place. Else, read on!I would like to create a very simple concept, but likely a really complex execution: a camera sensor and a screen that displays what that camera shows. I hope to create it from scratch, so not using Arduino/RPi modules. This is just for fun and learning so there are no time constraints and I'm not afraid of programming or PCB design. Although I have no electronic experience besides a couple of physics classes in college, I would love to take on this challenge.What I do know is that i can order some components separately, ie. an oled screen with a parallel interface and a CMOS sensor of some sort. My very limited logic states that i will probably need a microcontroller of some sort and a way to power the device. Whether or not this information is actually correct I don't actually know, so I'm hoping to get some direction from you smart folks!Anything you can think to assist me would be helpful, but here are some questions:-What components should I look at getting? I don't need storage, I just want to display a camera feed in one enclosed system, like a phone does when you open the camera app.- What should I expect to do/learn to do when putting these components together? Ideally no soldering since i have terrible hands for such things, but I'm willing to learn anyway and soldier through.- What are some good resources that can help me achieve this particular goal? I don't want to become an electronic engineer, or an expert in PCB design but I'd like to know just enough to create this one thing.Cheers,TL;DR: I'm a beginner who learns best when i have a tangible goal, such as creating a device that shows a camera feed. I would like to create this device and need some help starting out.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 27, 2018, 12:00:47 am
content: Quote from: im_a_kobe on July 26, 2018, 11:55:18 pmbefore anything i would like to ask... what do you think Arduino/RPi is?

author: im_a_kobe
author_rank: Newbie
timestamp: July 27, 2018, 12:09:23 am
content: Haha well when you put it that way... ¯\_(ツ)_/¯To be fair, I have done a little research on it and IthinkI could use an Arduino Mini as a microcontroller and explore using some compatible sensors/screens. But I don'tactually know, that's why I'm here. My thought process was that since Arduino/RPi are marketed as these things that could do everything, I might benefit from creating something that from the offset focuses on just one task, avoiding any extraneous parts and pieces. /I just want to display a live video feed, then down the line maybe start playing around with and learning about latencies/power etc. I'm not entirely opposed to Arduinos, and I'm curious to see any thoughts on the subject.Cheers
Starting a portable generator with a Milwaukee M18 battery? - Page 1
Forum section: electronics / beginners

author: SpookyGhost
author_rank: Contributor
timestamp: February 03, 2022, 07:55:10 pm
content: I have a portable generator. I use it very rarely, and it has electric start. I want to keep electric start, but remove the need to maintain a 12v lead acid batteryYou can get M18 battery holders that have pretty stout connectors:https://www.amazon.com/Milwaukee-Battery-Adapter-Connector-Injection/dp/B08HXBT21C/The only issue I see is that once the generator starts, there will be voltage coming back to the battery. Is there any way to stop the current coming back to the battery?Is this a good idea? I have no doubt a good M18 battery has enough current.

author: Renate
author_rank: Super Contributor
timestamp: February 04, 2022, 12:00:28 pm
content: You don't say what kind of generator. It makes a big difference.I have an Onan Microlite 2.8 kW. As it doesn't have a utility 12V output (like some utility generators) it only has a small 12V winding, a full-wave bridge and a resistor. It uses a dynamo for ignition so it only needs to make sure that the electric fuel pump and the control circuitry don't drain the battery. (To actually charge my batteries I have a 60 Ampere converter.)I would think that you'd have to add a diode and maybe a capacitor. Got a schematic?

author: jpanhalt
author_rank: Super Contributor
timestamp: February 04, 2022, 12:17:04 pm
content: How much current does your starter require? That is important. You do not want to draw more current from the lithium cells than what they are spec't at. For example, the 21700 cell used in the 12AH Milwaukee battery pack has various amperage ratings. Google showed ratings of 10A to 35A. Those are not amp-hours. They represent the maximum designed current.Drawing too much current from a lithium battery is bad for it. The duration of that drain is also important. So, an instantaneous overcurrent (say a few ms) is not as bad as something for a minute. The cell pack itself may have a current limiting circuit.A stout diode in the positive line line would prevent back charging.

author: Renate
author_rank: Super Contributor
timestamp: February 04, 2022, 12:25:16 pm
content: Quote from: jpanhalt on February 04, 2022, 12:17:04 pmIt wouldn't have to be that stout if you separated the starter feed.

author: SpookyGhost
author_rank: Contributor
timestamp: February 04, 2022, 05:32:44 pm
content: Thanks for the information guys, sometime this weekend I'll grab my clamp meter and see how much it pulls. I can't image its much though given how small the battery and cables areIts a Champion 100520, it has a 420cc engine
Starting a project, looking for resources to help.  - Page 1
Forum section: electronics / beginners

author: jfigure
author_rank: Newbie
timestamp: July 03, 2023, 05:16:41 am
content: I'm starting my first project, I've ordered a few things and have a relatively decent understanding of what I'm attempting to do.I'm having a bit of a hard time finding the information I need to get started. I'm completly ignorant to the best/most reliable resources in this hobby.The hardware:ESP32, TMC2209 Stepper Motor Drivers, two of these stepper driven actuators:https://www.robotdigg.com/product/1270/9-36V-DC-belt-driven-stepper-motor-linear-actuatorThe goal:Serve a page on localhost that will let me click some buttons and move the actuators a set amount.Long term goals:Move the actuators at a certain speed over time to maintain pressure on piston on a liquid that slowly loses pressure.I understand the general idea, have a bunch of programming experience, but there are definite gaps I need to fill before I can proceed. For example, understanding the wiring schematic of the motor/actuator is a must- I can't seem to find what I'm looking for. The stepper has 4 wires out, the actuator has 4 wires out. Seems like actuators with feedback have 5 wires commonly. Confused.Anyway- any resources to help with this project would be super helpful.

author: liaifat85
author_rank: Regular Contributor
timestamp: July 03, 2023, 07:25:22 am
content: I think BLYNK 2 will be good for this project. There are some widgets that you can use in BLYNK 2. Such as buttons, Gauss, slider etc. You can integrate those with your hardware.

author: Krystepan
author_rank: Newbie
timestamp: July 10, 2023, 09:26:17 am
content: According to the actuator documentation you've provided, the stepper motor has four wires for two pairs of coils inside stepper motor just like in the photo in the attachment.These wires just connect to the stepper motor driver outputs.Actuator has only 3 wires : black, red and green. Red is shorted to black when actuators reached inner position, green is shorted to black when actuator reached outer position. Use this signals as feedback to your controller about actuator position.You can also estimate actuator position by counting a stepper motor steps amount comes from your controller that controls stepper driver.Eg. one revolution of stepper motor equals 1 mm linear movement of actuator. You have to check it experimentally.

author: jfigure
author_rank: Newbie
timestamp: July 10, 2023, 04:03:24 pm
content: Quote from: Krystepan on July 10, 2023, 09:26:17 amWeird. The actuator has 4 wires (expected 3), the nema stepper has 4 as well (expected 4)I tried to open it, but seems like there is glue and/or something holding it all together.
Starting lead free soldering? - Page 1
Forum section: electronics / beginners

author: eugenenine
author_rank: Frequent Contributor
timestamp: February 13, 2017, 11:02:46 pm
content: I remember there used to be a lot of issues with lead free, is that still the case? Since I just bought a decent iron should I look into it again?If yes, what brand(s) of solder, flux, etc does everyone use?

author: ataradov
author_rank: Super Contributor
timestamp: February 13, 2017, 11:08:32 pm
content: Issues are still there - solder is harder to melt, it does not wet as well, so requires more toxic fluxes.And the main issue - what is that you are trying to achieve by doing this? I hardly see any point in doing lead free stuff for a home and hobby use.

author: Zero999
author_rank: Super Contributor
timestamp: February 13, 2017, 11:09:06 pm
content: If you're doing it commercially, then yes, in which case you probably won't be doing it by hand, unless it's the odd repair. If it's for hobbyist, educational or prototypes, then lead free soldering is of no benefit at all.

author: deadlylover
author_rank: Frequent Contributor
timestamp: February 14, 2017, 08:28:42 am
content: I use SN100C by Nihon Superior, it's really not that much hardship at all compared to leaded solder.

author: tautech
author_rank: Super Contributor
timestamp: February 14, 2017, 08:47:29 am
content: Quote from: eugenenine on February 13, 2017, 11:02:46 pmNo,enjoyyour new iron and Pb soldering.

author: Miyuki
author_rank: Frequent Contributor
timestamp: February 14, 2017, 09:25:15 am
content: Quote from: deadlylover on February 14, 2017, 08:28:42 amThis look interesting

author: GreyWoolfe
author_rank: Unknown
timestamp: February 14, 2017, 01:44:59 pm
content: Quote from: ataradov on February 13, 2017, 11:08:32 pmDon't forget shorter tip life due to higher temps to melt and the lead free is aggressive on tips.

author: eugenenine
author_rank: Frequent Contributor
timestamp: February 14, 2017, 03:26:00 pm
content: OK, I guess we'll call that a no then, sounds like still too much of an issue.

author: ConKbot
author_rank: Super Contributor
timestamp: February 14, 2017, 03:26:50 pm
content: Quote from: deadlylover on February 14, 2017, 08:28:42 amSn100C is good solder, very nice to work with compared to SAC305, strength isn't a compromise, etc. Not a crusty mess when you hand solder it. But its melting point is even higher than SAC305. For trying to hand solder to minimize lifting pads by a novice, Id still suggest 63/37 Sn/Pb
Starting on Lattice Radiant software with ICE40 FPGA - Page 1
Forum section: electronics / beginners

author: Akshar001
author_rank: Newbie
timestamp: September 11, 2021, 04:44:44 am
content: Hey,I am trying to run Radiant Software for ICE40 FPGA development, the problem i have is about linking external clock to top module.I didn't see any documents or can not understand it. I have easily done that thing on Arty A35 just using create_clock but in radiant it seems not working.Can anybody guid me here?

author: iMo
author_rank: Super Contributor
timestamp: September 11, 2021, 07:49:32 am
content: Do you mean how to create a constraint for the input clock?There is the constraint editor in the Radiant - you may define the clock parameters there.