hybridfree/eevblog-posts huggingface dataset:
Schematic review request - 555 timer led-cube, with actual pattern - Page 1
Forum section: electronics / beginners

author: Huulivoide
author_rank: Newbie
timestamp: October 25, 2015, 06:25:12 pm
content: I was hoping some could go over my schematic for 555 timer 3x3x3 led-cubewith an actual real pattern in it. Not just a CD4020 as seems to be popularon the interwebs.Sorry for the, somewhat messy, layout.The 4000 series chips in gschem, seem to be missing power pins fromthe symbols. So just assume the same ground and 4.5v supply for the 4029,4514 and 4017 chips.Pattern goes from layer 1 to 2 to 3 to 2 and then loops backto beginning. 1st and 3rd layers are the same, 2nd layer is a reversedversion of it.Spots that I think could problems.1. 4029 counter's UP/DOWN pin's pull-down resistor.2. The 4001 latch implementation.3. 4514, strobe pin. Do I need to input a clock signal here to make it work?4. The led circuit's general transistor structure and the base resistor values.List of parts that I believe should provide working blinker.* BC547B as the NPN transistors* BC556B as the PNP transistors* As for leds: 20mA, 2.6 Vdc* 1N4004 as the diodes.List of IC chips used with descriptions of their purpose and links to datasheets:555: Used to generate clock signal for primary layer animation counter.http://www.ti.com/lit/ds/symlink/ne555.pdfCD40001: NOR-gates, used to create a latch to switch animation direction.https://www.fairchildsemi.com/datasheets/CD/CD4001BC.pdfCD4029: Used as 4bit binary counter.http://www.ti.com/lit/ds/symlink/cd4029b.pdfCD4515: 4bit to 16 output decoding of the animation counter.http://www.ti.com/lit/ds/symlink/cd4029b.pdfCD4017: Decade counter, used to switch between layers, at the end of an animation cycle.http://pdf.datasheetcatalog.com/datasheets/90/108738_DS.pdfCD4070; XOR-gates to drive the layer power PNP-transistors with the CD4017.http://datasheet.octopart.com/CD4070BCM-Fairchild-datasheet-76777.pdf

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 28, 2015, 04:36:44 pm
content: Sure seems like a lot of trouble and a high parts count for not much pattern flexibility. Are you doing this as an exercise in TTL or something? More power to you, I love analog discrete circuits myself, but my eyeballs cross when I'm trying to figure out someone else's circuitry.I made a 4x4x4 cube and drove it with an Arduino Mega, so any pattern is easy to implement in software without making any hardware changes. Only 4 drive transistors and a handful of resistors are needed external to the Mega.Even this is pretty lame compared to some of the mcu-driven LED cubes out there.
Schematic symbol best practices - Page 1
Forum section: electronics / beginners

author: Deepak
author_rank: Regular Contributor
timestamp: March 07, 2019, 11:39:22 pm
content: So I'm working on a project that requires me to create some schematic symbols which don't already exist in the default library. Based on ones I've looked at previously I've picked up the following:Vxxup top and GND at the bottomInputs on the left, outputs on the rightGroup like pinsLeave space between unlike pinsDon't hide pinsDon't duplicate numbersHave I missed any other obvious guidelines?Also, I'm a bit unclear as to how to resolve the last two against something like a shield and the footprint I'm mapping to. Let's say it's a USB connector with four connections for the shield to the board. Obviously I'd have the Vbus, GND, and two data pins - but if I have one shield then there are threeorphanedpads on the footprint that have to be manually connected to the correct net. The alternative would be to put four shield pins with unique numbers on the schematic which also seems a bit insane. How do the pros handle it?
Schematic symbol - Page 1
Forum section: electronics / beginners

author: alex-sh
author_rank: Regular Contributor
timestamp: March 11, 2019, 11:50:15 am
content: Hello,I have come across this symbol in the schematic, which I believe it a thermistor.However, I do not understand 100ma and a symbol right next to it.Could somebody please enlighten me what this means?Many thanksAlex

author: Zero999
author_rank: Super Contributor
timestamp: March 11, 2019, 01:34:44 pm
content: It is a type of thermistor. It's a PTC resistor used for overcurrent protection. It performs the function of a self-resetting fuse. Its temperature rises, as the current increases, causing its resistance to increase and further heating towards the tripping point, when its temperature and resistance rapidly rises, causing it to limit the current to a very low level. When the current is interrupted and it's left to cool, its resistance drops and it's ready to go again.

author: alex-sh
author_rank: Regular Contributor
timestamp: March 11, 2019, 01:48:46 pm
content: Funny enough I have a few PTC thermistors and used them to protect the circuitries from overcurrents, but I have never seen such symbol in a schematic. Typically I see the one attached for PTC thermistors.Many thanks for your help Zero999!

author: WildMOSFET
author_rank: Contributor
timestamp: March 15, 2019, 09:32:25 pm
content: That symbol (with the "-") is also used for the NTCs, they are always thermistors which, however, work in contrast to PTCs: as the current increases, they reduce their resistance.
Schematic understanding... how do I interpret this? - Page 1
Forum section: electronics / beginners

author: Jupitus
author_rank: Contributor
timestamp: January 23, 2024, 04:34:10 pm
content: Hey all! May be a daft question, but can someone please explain to me how to interpret this on a schematic ?

author: TimNJ
author_rank: Super Contributor
timestamp: January 23, 2024, 04:44:04 pm
content: I'd guess it indicates a PCB "solder bridgeable" jumper.Something like the bottom four "parts" in the attached photo. Drag solder between the two pads to solder them together.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: January 23, 2024, 07:39:37 pm
content: My best guess other than what TimNJ said is an SMD fuse, as it looks like that componentsmighthave a current rating. 175mA fuse?

author: pcprogrammer
author_rank: Super Contributor
timestamp: January 23, 2024, 07:52:17 pm
content: The text above the symbol says it is a jumper with dimensions 43*39. The current being mentioned looks like a hint for others that it typically is 175mA.I find the solder-able jumper explanation far more likely then it being a fuse symbol.Edit: even the part reference PJP10 more likely points to a jumper than a fuse.

author: BrokenYugo
author_rank: Super Contributor
timestamp: January 23, 2024, 08:14:17 pm
content: I've seen something like this in a Chinese transistor radio kit, each stage of the circuit had a solder bridge on the Vcc trace and the expected current given. I think the idea was you were supposed to build it stage by stage and test to sort of confirm you built it right.
Schematic washer machine - Page 1
Forum section: electronics / beginners

author: Barajan
author_rank: Newbie
timestamp: September 15, 2018, 07:52:21 am
content: Hi ! I want to some sevice manual or schematic washer machine please help , thank

author: Signal32
author_rank: Frequent Contributor
timestamp: September 15, 2018, 07:59:03 am
content: hi you can find onlines, search fine, thank

author: SeanB
author_rank: Super Contributor
timestamp: September 15, 2018, 11:48:05 am
content: What washing machine, not exactly easy, as there are so many models, so many manufacturers and so many in age.

author: ebastler
author_rank: Super Contributor
timestamp: September 15, 2018, 08:13:38 pm
content: Quote from: Barajan on September 15, 2018, 07:52:21 amI prefer to wash my schematics by hand. It's much gentler on the ink.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: September 15, 2018, 08:16:38 pm
content: Quote from: ebastler on September 15, 2018, 08:13:38 pmI go to the pressure washer myself, depends on how much pesky ink is on the drawing. But sometimes I just use the kitchen sink.

author: Seekonk
author_rank: Super Contributor
timestamp: September 15, 2018, 11:20:17 pm
content: Every washing machine and dryer I've ever seen has the schematic inside near the control panel. The fact that you can't google the model number and find a lot of service information online indicates you won't likely have any luck fixing it.

author: xrunner
author_rank: Super Contributor
timestamp: September 15, 2018, 11:30:27 pm
content: Quote from: Barajan on September 15, 2018, 07:52:21 amWe can help you help yourself perhaps.Just Google for the repair guide or some such term like this -"Sears washer repair guide"Since I don't know what make and model you have it's just an example. Keep searching until you find what you are looking for. That's all we would do.

author: Cerebus
author_rank: Super Contributor
timestamp: September 16, 2018, 01:03:18 am
content: Quote from: ebastler on September 15, 2018, 08:13:38 pmI get the luxury naked virgin wash service, my schematics have never been softer and are nowsomuch nicer next to my nB?@?a??0?e?n?+?I/eI?DCARRIER LOST

author: t1d
author_rank: Super Contributor
timestamp: September 16, 2018, 06:30:20 am
content: The internet parts suppliers have videos, on how to make repairs. They also have the complete parts diagrams... It is likely that they have the electrical schematics, too...Here is an example. See the "Repair Help" section.https://www.repairclinic.com/PartDetail/Timer/WH12X10527/2319492
schematics - Page 1
Forum section: electronics / beginners

author: krappleby
author_rank: Contributor
timestamp: April 09, 2018, 11:11:00 pm
content: is their a website/database of schematics, that people can use..say i wanted to look up a schematic of lets say a sony surround sound system, would i have to go to sony and ask for one, or is their a repository containing them?cheerskeith

author: Audioguru
author_rank: Super Contributor
timestamp: April 09, 2018, 11:35:43 pm
content: Most of us would look in Google for anything. But you must say the model number of the Sony surround system you want the schematic for.

author: krappleby
author_rank: Contributor
timestamp: April 09, 2018, 11:39:55 pm
content: hi, thanks, the sony was just an example dont want one, lol. just wondered if their was a repository or something..cheers

author: Audioguru
author_rank: Super Contributor
timestamp: April 09, 2018, 11:57:28 pm
content: There are some websites that have the service manuals for electronic products and many of those websites charge a fee for your download. I have never needed one.

author: Cerebus
author_rank: Super Contributor
timestamp: April 10, 2018, 02:00:44 am
content: There is a huge repository of manuals for test gearhttp://www.ko4bb.com/getsimple/index.php?id=manuals]at http://www.ko4bb.com/getsimple/index.php?id=manuals. Many of them are service manuals that include full schematics. There is a lot of mileage in looking at those, figuring out what the circuitry does and why the designers made the choices they did.Full service manuals with schematics for consumer electronics are fewer and further between. There are a few sites that have them, but it's pot luck whether you find a 'here's the board to swap' service manual, or one with detailed troubleshooting information and/or schematics. The best approach to finding these is to search on your favourite search engine for a specific product including model number. Beware, there are a few sites that try to charge you for manuals that can be freely downloaded from other sites.To get you started, there are manuals for all sorts of things athttps://archive.org/details/manuals.

author: Burczyk
author_rank: Contributor
timestamp: April 10, 2018, 12:35:07 pm
content: Onhttps://www.radiomuseum.org/you can find alot of manuals and schematics for old radios and test gear (mostly vacuum tube era).

author: palpurul
author_rank: Regular Contributor
timestamp: April 12, 2018, 12:07:49 pm
content: I usually use application notes from IC manufacturers or datasheets. They are reliable.

author: mzacharias
author_rank: Frequent Contributor
timestamp: April 12, 2018, 09:04:22 pm
content: https://www.eserviceinfo.com/https://elektrotanya.com/https://www.hifiengine.com/(requires registration)
Schematics for a basic CC/CV lab power supply - Page 1
Forum section: electronics / beginners

author: ketszim
author_rank: Newbie
timestamp: July 29, 2016, 06:59:33 am
content: Hey everyone!So I'm very much a beginner and I'm hoping to start by building a Variable Voltage and Current Limit PSU. Does anyone have any schematics for me to follow or any suggestions? Any help would be much appreciated. Also if you know of any good sources for parts you could leave them below.Thanks.

author: MosherIV
author_rank: Super Contributor
timestamp: July 29, 2016, 07:10:35 am
content: http://www.microsyl.com/index.php/2010/03/31/bench-power-supply-0-25v-0-5amp/

author: MarkF
author_rank: Super Contributor
timestamp: July 29, 2016, 08:36:22 pm
content: Peter Oaks videos walk you through a power supply he designed:
Schematics for Magnavox Power Supply - Page 1
Forum section: electronics / beginners

author: manfriend
author_rank: Newbie
timestamp: July 24, 2018, 10:29:20 pm
content: I have scoured the web looking for schematics of a Magnavox 47MF439B/F7 and cannot find them. Specifically I need to power board schematics, board #PLHC-T829A and the white tag has #3PAGC10004A-R. I know these are used in other model TVs, or were, It's a LCD TV, but what I've read these PSUs were always replaced if they had a fault and the bad units shipped away to be repaired and put on the shelf. Still, these aren't state secrets, right? There has to be schematics for it some where! I attached some images. I appreciate any help.
Schematics for Switching Power Supply S-30-5 - Page 1
Forum section: electronics / beginners

author: tpd
author_rank: Contributor
timestamp: January 24, 2024, 10:26:53 am
content: Hi,Is there schematics for this Chinese switcher?https://katgates.com/assets/uploads/files/5V_6A.pdf

author: coromonadalix
author_rank: Super Contributor
timestamp: January 24, 2024, 05:05:49 pm
content: you open them and check for the main ic markings, and maybe find a datasheet ,,
Schmitt jelly bean - Page 1
Forum section: electronics / beginners

author: PerranOak
author_rank: Frequent Contributor
timestamp: September 27, 2018, 03:53:00 pm
content: I want to get a Schmitt trigger (hex?) to experiment on.Any suggestions for an all purpose example please?Thanks.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: September 27, 2018, 04:13:26 pm
content: 74HC14

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 27, 2018, 04:15:17 pm
content: ALL purpose? Impossible!The other likely candidate is CD40106 (15V CMOS, slow and weak).74HC is the go-to 5V, reasonably fast CMOS family.Tim

author: PerranOak
author_rank: Frequent Contributor
timestamp: September 27, 2018, 04:59:56 pm
content: Beauty, thank you.I know it's hard to recommend a part when I am so vague but until I get experimenting I don't know what I need.I'll go for the 74HC14.
Schmitt Trigger VS transistor  - Page 1
Forum section: electronics / beginners

author: amel
author_rank: Newbie
timestamp: May 24, 2021, 09:21:13 am
content: Hello,can you please explain for me what is the différence between Shmitt trigger and transistor, especially in driving LEDs and in current consumption.Regards,

author: Moriambar
author_rank: Unknown
timestamp: May 24, 2021, 09:46:30 am
content: Quote from: amel on May 24, 2021, 09:21:13 amI'll answer the first part.A transistor is an active component, made by doping silicon and exploits some properties of the junction between doped regions (bjt) or applies some electric field to the doped silicon in order to control coduction (FETs).A transistor can be hooked up in many ways. As a switch its output terminal gets pulled up or pulled down (depending on the transistor) depending on the voltage or current (FET vs BJT) applied at its "control" terminal. As a current source the transistor sources or sinks a constant amount of current depending on how you hooked it up. As an amplifier it enhances the input signal, as a follower gives the same signal but makes following component see a lower impedance, ie: decouples what lies before it to what lies after it, and so on.A schmitt trigger is basically a "specialized op amp", you can actually obtain something similar by giving an operational amplifier a positive feedback. What it's used for is basically to make sharp transitions in digital logic since once the signal goes over some threshold the trigger saturates at Vcc, negative yields Vee.A schmitt trigger is generally made by many transistors.As per driving leds... I don't know what usage you could make of a schmitt trigger.EDIT: While for the transistor you can drive leds either using them as a current source or sink or a simple switch.
Schmitttrigger doesnt work - Page 1
Forum section: electronics / beginners

author: JuculianD
author_rank: Contributor
timestamp: October 15, 2018, 03:21:32 pm
content: Hello!I am not very experienced in the use of schmitt triggers (experience=0) and designed a circuit.For my application, I need 3 channels but I don't want to have an inverted signal.I have used a 74HC14D (NXP) which has 6 channels.To not have an inverted signal, I have connected the output to the input of an other channel of the chip. Therefore, in my theory, the signal should be inverted again.It is not a nice solution, I know, but I thought, I could just use those 3 spare channels because I don't need them anyway and save using an inverting circuit.BUT!It doesn't work.I have made some PCBs and tried it out, but no matter which input signal I put in, the output is high all the time.Can somebody help?Is my circuit not possible, or ist the error somewhere else?(I am using it in my 3D Printer, maybe I am reading it out wrong. I will make some measurements now.)Thankyou very much!Julian.

author: retrolefty
author_rank: Super Contributor
timestamp: October 15, 2018, 03:31:24 pm
content: Wiring diagram appears correct. Nothing special about schmitt trigger so better check your testing procedure or test equipment usage.Good luck

author: JuculianD
author_rank: Contributor
timestamp: October 15, 2018, 03:38:59 pm
content: Thank you very much.You are making me couragous, because I was quite sure that my circuit is crap.I will test it now and give feedback soon.

author: JuculianD
author_rank: Contributor
timestamp: October 15, 2018, 04:00:39 pm
content: You are right!It works as it should.There is something wrong with my chinese crappy board, it is too bad engineered to compare 0,00V to 5,1V.Thanks for all the help,the thread can be closed.

author: MarkF
author_rank: Super Contributor
timestamp: October 15, 2018, 04:06:54 pm
content: Glad you have it working.You might consider a cleaner trace routing:

author: JuculianD
author_rank: Contributor
timestamp: October 15, 2018, 04:31:38 pm
content: Oh, yeah.I dont care about the schematics, but the PCB looks odd.I must admit, I was just using the autrouter...Thank you for your help,this forum and Dave's videos are helping me a lot
School assignment help: Electronics tech employers, a few questions? - Page 1
Forum section: electronics / beginners

author: newastrocity
author_rank: Contributor
timestamp: November 20, 2017, 08:48:23 am
content: Hi there,Being completely honest, my first quarter is nearing its end in my electronics technology program. I need to speak to 3 people from 3 different companies, to ask them about 12 minutes worth of questions about the Electronics industry and what kinds of things they are looking for in hiring new Electronics technicians-I live in Software country, and am having a hard time in my social network making links with people who hire Electronic techs.Could anyone help a struggling student out, and answer some basic questions about their company? It would be much appreciated, email or a call would be fine, whichever you prefer. Thanks!Edit: To be clear, I work and study full time, so I'm not looking for a job, just industry insight. You could be a big help even if your company is not currently hiring. Thanks again!

author: Shpak
author_rank: Newbie
timestamp: November 20, 2017, 02:49:59 pm
content: You can write me a private message and I'll give you my E-mail so you can send me the questions.

author: newastrocity
author_rank: Contributor
timestamp: November 20, 2017, 05:59:22 pm
content: PMed, thank you!

author: JoeO
author_rank: Frequent Contributor
timestamp: November 21, 2017, 04:00:12 am
content: Quote from: newastrocity on November 20, 2017, 08:48:23 amIt sure would help if you told us what country you are in and where in that country you live.

author: newastrocity
author_rank: Contributor
timestamp: November 23, 2017, 03:36:48 am
content: Good point, I'm in the Seattle area in the USA. Thanks!
School Piezo Energy Harvesting Experiment - Page 1
Forum section: electronics / beginners

author: boatanchorguy
author_rank: Newbie
timestamp: January 16, 2018, 03:47:17 am
content: Helping my granddaughter with a HS project on the piezoelectric effect and renewable energy. She placed a 30mm piezo disc under the heel of her sneaker that inputs into a Schottky (1N5711) full wave bridge whose output is across a 47uF 50V electrolytic. Wearing the PCB with bridge/cap on the outside of her sneaker she walked on a treadmill at a casual rate (1 step/second) and we data logged the slow charge up of the capacitor. It took just about 7 minutes to plateau at around 5.25 VDC. Without the capacitor - the open circuit voltage from the bridge is quite high --- 20-60 Vdc but when the capacitor is added it loads down to initially a few mVdc and slowly comes up as the cap is charged by the piezo. We want to get some estimate of the energy generated per step recognizing this is on the microjoule or nanojoule level. I was going to use the equation for stored energy in capacitor = ½ C x V^2 and divide by total seconds to reach the exponential plateau of the 5.25Vdc maximal charge. Next step will be to add a tiny LiPo charger or play with the LTC3588 chip. Any advice on how to get this estimate of piezo power per step would be appreciated.Thank you in advance

author: tggzzz
author_rank: Super Contributor
timestamp: January 16, 2018, 08:38:50 am
content: Please don't "double post"; it confuses everybody.I suggest the other post is the better place to respond.
School project help - connecting meters - Page 1
Forum section: electronics / beginners

author: whatishername8
author_rank: Newbie
timestamp: May 06, 2021, 03:21:07 pm
content: Hi!So we have this school project and they didn't quite explain how we're supposed to use all of the instruments. So for example, for the circuit in the picture we're supposed to check kirchoff's laws. I know that the ampermeter is connected in series and the voltmeter is connected in parallel.... I just don't quite see enought places in this model to connect them. For example if I need to check the first kirchoff law for let's say node number 1, i can see that for current 13 i can connect the ampermeter instead of the short circuit....for current 14 i can probably circumvent and touch one part to the resistor and connect the other one through the connector of the voltage source. But, current 12 is baffling me, i don't see where I'm supposed to put the connectors for the ampermeter. In the pictures I sent there is a scheme of the circuit, the irl model and how the resistors look irl. The connectors are what we call "banana connectors" and they have holes in them if we need to plug something in as a parallel circuit. The resistors plug inside of the circuit by using those probe-like legs that you can see in one of the pictures. Up top, I think there are also places where you can touch the resistors for measuring.I'm sorry if this is confusing, they didn't explain anything and English isn't my primary language... I hope someone can help!P.S. Sorry for the bad quality, i had to take screenshots off of online lectures.Thank you in advance!

author: ledtester
author_rank: Super Contributor
timestamp: May 06, 2021, 04:15:56 pm
content: To measure the current through a resistor you can measure the voltage across the resistor and use Ohm's law: V = I*R.QuoteCan you show where exactly where you would use the ammeter in this case?
School project question! - Page 1
Forum section: electronics / beginners

author: reitman82
author_rank: Newbie
timestamp: November 11, 2017, 05:58:20 pm
content: Hey everyone, James Stewart here. I was wondering if doing an interview (via Email) here would be ok? It's a school project for my Principles of Engineering class. If I get the OK then I can go over the logistics!Thanks, James

author: ataradov
author_rank: Super Contributor
timestamp: November 11, 2017, 07:39:18 pm
content: If you are asking if you can ask questions over email, I doubt you will find a lot of takers. But there is a tool from google that lets you collect answers to a number of questions. You will probably have more luck with that.
Schottkey Diode purpose and placment - Page 1
Forum section: electronics / beginners

author: stratogazer
author_rank: Contributor
timestamp: April 21, 2015, 02:00:33 pm
content: Hi forum Members. Another newbie here. I would like some help with diodes, see attachment below. This portion of the circuit is from a DS2712 battery charger. In the Parallel configuration with Switch Mode Current Limiting there is a filter/ inductor protected by 2 Schottkey diodes. In the schematic, no guidance is given as to the sizing of these diodes. The current output is supposed to be limited to 2.0A. Input voltage is +5VDC. How would I calculate sizing the diodes? Thanks in advance for any advice / help.

author: janoc
author_rank: Super Contributor
timestamp: April 21, 2015, 03:48:01 pm
content: That is not switch mode "current limiting" but a switch mode currentregulation!(figure 5. of the datasheet, p. 8:http://pdfserv.maximintegrated.com/en/ds/DS2711-DS2712.pdf)That part of the circuit is a switch mode buck converter and the diodes are necessary to make the back EMF current generated on the inductor to go in the right direction. Here is an explanation of how it works:http://www.learnabout-electronics.org/PSU/psu31.phpThe diodes need to be Schottky or fast recovery diodes, otherwise you would get significant losses on them - they must turn on and off very quickly. How to size them depends on the inductor and the currents you are anticipating there.

author: stratogazer
author_rank: Contributor
timestamp: April 21, 2015, 04:56:40 pm
content: Thanks janoc! And thanks for the link. That was the missing piece of the puzzle. I would normally put current regulation in the power supply but this does that for me. Thanks for the help!

author: janoc
author_rank: Super Contributor
timestamp: April 21, 2015, 08:43:13 pm
content: Quote from: stratogazer on April 21, 2015, 04:56:40 pmThe point of that chip is that it is a charging controller, so it needs to regulate the charging current somehow. Either it does it linearly, which is simple but inefficient or you can use a switch mode regulator that is a lot more efficient at the expense of some complexity.Regulation in the PSU won't help you anything here, because the chip can't control it.Quote from: stratogazer on April 21, 2015, 04:56:40 pmWelcome.

author: Andrejka
author_rank: Contributor
timestamp: November 12, 2017, 06:10:29 pm
content: Hello,I maked NiMH charger with DS2712 exactly as explained in datasheet, but switching transistor FCX718 temperature is raising very quickly. Maybe someone can suggest what is wrong?ThanksAndrej

author: janoc
author_rank: Super Contributor
timestamp: November 12, 2017, 07:47:04 pm
content: You are resurrecting an over 2 years old thread on an unrelated issue. Better start a new topic. And post a schematic of what exactly you have tried to build and photo of your construction.Assuming that you didn't screw something up in the build, if those transistors are getting hot they will likely need a heatsink or you need to use smaller current with them.
Schottkey Diodes as blocking diodes for battery management in solar panel  - Page 1
Forum section: electronics / beginners

author: Mattjd
author_rank: Regular Contributor
timestamp: December 10, 2019, 12:43:31 am
content: Looking over some IC for battery management systems for batteries used in PV cell applications.Looking at LT3652 specifically.https://www.analog.com/media/en/technical-documentation/data-sheets/3652fe.pdfThe exact application of this battery manager is for a cubesat.I was wondering if someone could give a brief rundown on those blocking diodes function in the datasheet.Another source I found is calling them day and night diodes for Day-Night switching. I am guessing during eclipse of the cubesat, somehow those diodes switch to use battery as source?https://imgur.com/a/8PRp1Ae

author: Mattjd
author_rank: Regular Contributor
timestamp: December 10, 2019, 12:47:12 am
content: Really what I am thinking is that when the voltage from solar panels drops during eclipse it causes that diode connected to the battery to conduct and thus the battery discharges.

author: Jwillis
author_rank: Super Contributor
timestamp: December 10, 2019, 04:35:04 am
content: I'm not sure if this is important.Schottky diodes havea very fast recovery compared to conventional diodes but schottky diodes also exhibit higher leakage current than conventional diodes as the temperature increases .More so at higher voltages.I should correct by saying that Schottky diodes have no recovery because of design. No p-type semiconductor so no holes when reverse biased. So nothing to recover.

author: BravoV
author_rank: Super Contributor
timestamp: December 10, 2019, 04:36:41 am
content: Google for SM74611

author: David Hess
author_rank: Super Contributor
timestamp: December 10, 2019, 07:53:06 pm
content: Schottky diodes are just used for lower forward voltage drop. Standard rectifiers could be used with some loss of efficiency or transistors could be used for greater efficiency.The first diode isolates the panels from the battery when operating on battery and the second diode isolates the battery from the panels when operating on the panels. This mode of operation will not be suitable if the load is expecting a restricted voltage range because the panel voltage is not regulated.The application examples at the end of the datasheet lack both diodes and connect the load directly to the batteryQuote from: Jwillis on December 10, 2019, 04:35:04 amThat is not strictly true in most cases. Because of how high voltage schottky diodes are constructed with a guard ring, which is practically all of them, they have an additional PN junction in parallel so at high currents the PN junction also conducts creating reverse recovery which is revealed as a long recovery tail. In most applications this can be ignored unless the peak currents are high.
Schumacher 5212 A battery charger  - Page 1
Forum section: electronics / beginners

author: cmvalerius
author_rank: Newbie
timestamp: April 25, 2024, 02:26:44 pm
content: Both battery clamps fell off and I’m not sure which is positive and which is negativeOne goes to circuit board, one goes to small white plug in? Can anyone help?

author: xvr
author_rank: Frequent Contributor
timestamp: April 25, 2024, 03:49:27 pm
content: Test them with DMM

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 25, 2024, 04:32:01 pm
content: You can use a VOM too.
Schwinn 3 mode Bicycle Safety Light question - Page 1
Forum section: electronics / beginners

author: sambonator
author_rank: Regular Contributor
timestamp: March 14, 2019, 01:31:04 am
content: So in my pursuit to learn more about analog circuits, I tore down my Schwinn bike safety light.It has 1 button that toggles the LED's between on, flashing, and off.I've identified a 22Ω resistor, 0.95µF capacitor (by measurement), and what looks like a transistor... can anyone tell what that is?How does that allow me 3 modes of operation with a pushbutton?Attached at the pictures of the unit.Thank you!

author: Zero999
author_rank: Super Contributor
timestamp: March 14, 2019, 09:01:57 am
content: The capacitor has 105 written next to it, which means 10 00000pF or 1µF. It's probably for supply decoupling, but there's a possibility it's for timing.The resistor no doubt limits the current through the LED.The transistor lookalike device is an integrated circuit but without the part number your guess is as good as anyone's.

author: sambonator
author_rank: Regular Contributor
timestamp: March 14, 2019, 04:57:46 pm
content: Quote from: Zero999 on March 14, 2019, 09:01:57 amThank you Zero999. Didn't realize 105 was referring to the capacitor value. Another step forward in reading printed circuit boards!I'll dig around a bit to see if I can find info on this IC and post if I find it.Thank you for your analysis!

author: Kasper
author_rank: Frequent Contributor
timestamp: March 14, 2019, 08:18:55 pm
content: I am betting the IC is a micro controller (MCU).

author: AndyC_772
author_rank: Super Contributor
timestamp: March 14, 2019, 08:45:22 pm
content: You might struggle to find exactly what it is. Packages this small don't have room on them to write the full part number, so manufacturers use a cryptic few characters instead.Add to that the fact that it's quite likely to be an Asian market device that isn't sold in western markets, and may not have a data sheet in English.Chances are it's something like this, though:http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8127-AVR-8-bit-Microcontroller-ATtiny4-ATtiny5-ATtiny9-ATtiny10_Datasheet-Summary.pdf

author: Zero999
author_rank: Super Contributor
timestamp: March 14, 2019, 08:56:59 pm
content: Quote from: Kasper on March 14, 2019, 08:18:55 pmPossibly but I don't recall seeing a five pin MCU before. Six pins is the lowest MCUs normally go. I think it's more likely an ASIC.I'm surprised it's in a surface mount package and not chip on board, which is more common for this sort of thing.
Sciensta soldering kit - Page 1
Forum section: electronics / beginners

author: Alloabear
author_rank: Newbie
timestamp: January 17, 2025, 08:58:12 pm
content: https://amzn.eu/d/hfkuVMUHi all, absolute beginner here. So ive began soldering very recently and started doing those starter kits basically for kids.But this one hasn't turned out as well as I'd have liked. It turns on but the two led screens aren't working as they should. For a start they have different brightnesses and more lights are on than there should be. So there is no discernable distinction in numbers etc.I've checked all my joints for continuity, changed the triode and checked to see if I'd missed any joints for soldering.Would anyone have any ideas what noob mistake I've made here or is it possible that the screens/chip are faulty?Thanks for any advice, I know it's not a massive problem but it's frustrating none the less

author: ataradov
author_rank: Super Contributor
timestamp: January 17, 2025, 10:11:59 pm
content: Can you show some pictures?This is just a really shitty kit. They are relying on the I/O pins for the current limiting for the LEDs. This is really bad and can lead to all sorts of issues.If it is doing anything at all, there is a good chance it is working as expected, it is just not expected to work well.

author: Alloabear
author_rank: Newbie
timestamp: January 18, 2025, 12:35:05 pm
content: Thanks for the reply. Here is a couple of photos. Pick apart my soldering at will hahahttps://postimg.cc/HV2PqSWWhttps://postimg.cc/gL6LvtMV

author: ataradov
author_rank: Super Contributor
timestamp: January 18, 2025, 03:29:22 pm
content: I would double and triple check that you have them in a correct orientation. It is hard to tell if it is correct from thew blurry dark picture.Those displays have alignment indents and protrusions. If I'm not mistaken you should have indents on the bottom of the board. Pin 1 is next to an indent.

author: Shock
author_rank: Super Contributor
timestamp: January 18, 2025, 03:30:13 pm
content: Please don't post shortened URLs to forums learn how to post a URL and delete all the affiliate and tracking crap.

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: January 30, 2025, 09:27:08 am
content: Since you have checked all of the joints and found no mistake, I think it's a faulty hardware.
SCL pin to VCC - Page 1
Forum section: electronics / beginners

author: manubali
author_rank: Contributor
timestamp: April 07, 2018, 05:50:06 am
content: hi, can anyone explain scl pin of 74hc595n is connected to vcc in this schematic?

author: ataradov
author_rank: Super Contributor
timestamp: April 07, 2018, 05:56:24 am
content: SRCLR (or SCL how it is called here) pin is active low, and they did not need to ever clear the contents of the registers.

author: Rerouter
author_rank: Super Contributor
timestamp: April 07, 2018, 06:04:26 am
content: http://www.ti.com/lit/ds/symlink/sn74hc595.pdfhave a read on the the datasheet, when ~SCLEAR is pulled low it clears the registers, so they have tied it high to keep them from being cleared, it could lead to a weird state on poweron, but i am assuming the device wakes up pretty quickly.

author: manubali
author_rank: Contributor
timestamp: April 07, 2018, 06:08:55 am
content: i thought SCL means clock line as in arduino

author: ataradov
author_rank: Super Contributor
timestamp: April 07, 2018, 06:10:37 am
content: Well, the datasheet is pretty clear on what it means. Also, do you see those helpful circles and triangles on the symbol? They are there for a reason. Circle denotes active low level, and triangle is a clock input (or signal active on transition). Makes things easier to read, even if you don't know what the chip does.

author: medical-nerd
author_rank: Regular Contributor
timestamp: April 07, 2018, 02:57:45 pm
content: Quote from: ataradov on April 07, 2018, 06:10:37 amThanks - I never knew that all these years as a hobbyist.Cheers

author: Bassman59
author_rank: Super Contributor
timestamp: April 09, 2018, 02:23:59 am
content: Quote from: Rerouter on April 07, 2018, 06:04:26 amSince all the chip does is drive LEDs, as soon as the micro/master loads the first word into it, the outputs assume correct states. As you suggest, that should happen "quickly," so a reset isn't really necessary here.
Scope 10x probe voltage limit - Page 1
Forum section: electronics / beginners

author: OutbackBob
author_rank: Contributor
timestamp: March 09, 2015, 07:18:53 am
content: Hey guys,Quick noob question, if my scope inputs are rated to 300V and I probe 32V with my probe set at 10x, will the magic smoke escape from my shinny new scope?Thanks.

author: tautech
author_rank: Super Contributor
timestamp: March 09, 2015, 07:50:02 am
content: You scope will see only 3.2 V, yes the 10x that people talk of is confusing for learners, it really is a divide by 10 setting.Be sure to set the channel input to match the probe for the on screen measurements to be accurate.

author: tggzzz
author_rank: Super Contributor
timestamp: March 09, 2015, 10:44:30 am
content: Note that the probe has voltage limits too, and those limits are a function of frequency. Check the actual specs for frequencies above 10MHz.
Scope cables - any recommendations? - Page 1
Forum section: electronics / beginners

author: Omrieinbar
author_rank: Newbie
timestamp: November 18, 2019, 08:01:23 pm
content: Hi,I'm not new to electronic/ scopes but in the electronics lab we always used RG-58 coaxes to connect to the scope, this cable is too heavy for connecting to my current projects (it literally pulls my work of the table), any recommendation for other coaxes? I need to create my own scope probes and i don't have much experience doing this.Thanks

author: tggzzz
author_rank: Super Contributor
timestamp: November 18, 2019, 08:25:47 pm
content: *10 "high" impedance probes are made with special lossy flexible coax, not standard RF coax. Exception: Z0 resistive divider probes, which require a 50ohm termination in the scope.For much more information about an important subject, see the references athttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/

author: magic
author_rank: Super Contributor
timestamp: November 18, 2019, 08:45:29 pm
content: Scope probes are no easy thing to build, but RG-58 presumably implies BNC to BNC patchcords rather than probes. In which case you could buy RG-174 patchcords (3mm diameter). Not sure if anything thinner is available with BNC.Other than that, put a book on the cable to keep it from sliding off

author: GerryR
author_rank: Frequent Contributor
timestamp: November 18, 2019, 10:44:51 pm
content: I use RG316 terminated in BNC's and / or SMA's. It is a little stiff but still workable. I'm pretty sure it is about the same diameter as RG174.
Scope capture - sending to signal generator.  - Page 1
Forum section: electronics / beginners

author: Ozzyla
author_rank: Newbie
timestamp: December 30, 2019, 09:20:21 am
content: Hi all,I’m not an electrical tech but a motor mechanic that sets up EFI and wiring looms.What I’m trying to do is capture a REF and SYNC signal from an EFI engine and copy the capture to my signal generator.Is this possible? I have looked around on the net but did not find a lot so far so I thought I would ask here.DetailsSignalRef 38 – 2 teeth from a high-speed Hall sensor twice per cycleSYNC 1 tooth per cycle Hall sensorScope Rigol (DS2072)Sig Generator Rigol (DG1032)So the question is, can I capture and save the above using 2 channels and load them up in the sig generator to output for testing without the engine running down the track also for future projects?I see there is some software for the Sig generator to make up arbitrary signals etc, Is that what is needed to make up something like that? I’d like to copy exactly what the engine is producing so I know it is an exact copy.Any advice would be appreciated.ThanksSteven

author: pwlps
author_rank: Frequent Contributor
timestamp: December 30, 2019, 05:34:03 pm
content: from the DG1000Z series user manual:- page 2-75:Arb FileStore the user-defined arbitrary waveform in internal or external memory in“*.RAF” format....etc.- page 2-72:DG1000Z also could interconnect with RIGOL oscilloscope which supports USB-TMCseamlessly and rebuilt and output the waveform data collected by the oscilloscopelosslessly.

author: Ozzyla
author_rank: Newbie
timestamp: December 31, 2019, 06:08:25 am
content: Well i had a go at it, Using the USB i did manage to get a pattern but it was not like what was on the scope so I tried to save a csv file to a USB stick and thenread it on the DG1032, no matted how i did it and what format i tried it always came up with an error, invalid file or something like that.Not sure what im doing wrong, seems like it should be an easy task?Steven
Scope Ch1-Ch2 vs Ch3-Ch4 - Page 1
Forum section: electronics / beginners

author: Meshka7
author_rank: Contributor
timestamp: February 28, 2015, 10:04:00 pm
content: Does anyone know if any of the cheap scopes such as Rigol etc can do Ch1-Ch2 vs Ch3-Ch4 (the - is minus sign). I know scopes can do X-Y mode using two channels but what if I want to do differential mode on 2 pairs of channels then one differential mode vs another differential mode.I would imagine with digital scope that would be a trivial function to implement. Any idea? Since this would be one of the very few reasons I would want to go to a 4-Ch scope. This would be a great way to learn about diode curves etc. Right now to make a simple curve trace, I have to bypass the ground lead from my function generator. Works quite well but a little dangerous.Of course if it can do more than one pair of differentials that would be a plus even without the X-Y mode.Thanks!

author: max666
author_rank: Frequent Contributor
timestamp: March 01, 2015, 12:12:58 am
content: I just checked my DS1074Z, and as far as I'm aware, it can only show one math trace.

author: electr_peter
author_rank: Unknown
timestamp: March 01, 2015, 07:10:00 pm
content: You can only have one math operation, so no. Similar question has been discussed here:https://www.eevblog.com/forum/testgear/new-rigol-ds1054z-oscilloscope/msg620164/#msg620164
scope frequency readout - Page 1
Forum section: electronics / beginners

author: m3vuv
author_rank: Super Contributor
timestamp: December 27, 2021, 04:39:16 am
content: Hi all ive a hp 54503a 500mhz scope,when trying to measure the output of my nanovna the readings i get are all low for the frequency when using the time markers on the peak to peak of the displayed waveform,as fas as i know the nanovna works using the harmonics of the frequency its set at,is there a way to display the same frequency on the scope that the vna is set to output and not the fundamental frequency as it seems to do at the moment?.tia.
Scope help - Page 1
Forum section: electronics / beginners

author: awwende
author_rank: Contributor
timestamp: September 12, 2011, 02:00:21 am
content: So the story is, I'm working on a small class D tesla coil/plasma speaker and was working on testing my iphone isolation circuit, which will be using a fiber optic cable. As I was trying to measure an output my screen froze up and displayed an error code:"Illegal Instruction: 3849F4H"It's an HP 54600A 100MHz scope (bulky but I love the thing). I've searched google with no luck, and even though it's a copyright 1997 scope I even checked HPs website for technical support (out of desperation). I tried taking it apart to look for a CMOS battery since it displays even after I disconnect and reconnect power, but couldn't find the stupid thing.Does anyone know what's wrong or how I can fix it?

author: Psi
author_rank: Super Contributor
timestamp: September 12, 2011, 03:11:29 am
content: Dunno,but here is the service manual with schematicshttp://www.home.agilent.com/agilent/redirector.jspx?action=doc&lc=eng&cc=CA&id=1517712&ltype=External%20FileHave you looked over the pcb for anything obvious, like bulging capacitors?

author: w2aew
author_rank: Super Contributor
timestamp: September 12, 2011, 03:32:25 am
content: Various manuals for the that scope can be found on this page:http://128.238.9.201/~kurt/manuals/manuals/HP%20Agilent/I took a brief look at the service manual there, and it didn't initially appear to provide much help with respect to any error codes. In the Troubleshooting section, it describes a couple of built in self tests, and that if they fail, then replace the system board. Not very helpful for doing a component level repair. It does describe a little about checking out various systems, so maybe you'll be able to narrow it down...

author: awwende
author_rank: Contributor
timestamp: September 12, 2011, 04:32:23 am
content: Yes, I've looked the board over for obvious problems but it all looks fine from what I can tell.

author: rf-loop
author_rank: Super Contributor
timestamp: September 12, 2011, 07:11:43 pm
content: Quote from: awwende on September 12, 2011, 02:00:21 amHP use (Dallas or equivelent ) NVRAM what includes inside Li batteries. You can not measure batt voltage.I do not know this model NVRAM (I have not anymore these scopes) but I have fixed lot of 5450x series and this model keep cal data in NVRAM. But It can recovery just driving full selfcal routines after first defaulting cal data.Only what I know about 54600 serie is that it have also NVRAM and typical battery life is (depending many factors) 10 - 20 years. It is HP designed lifetime limit for this product.If it tell in selfcheck nvram ok, it still do not know battery status.But first, reset to decfalut (factory cal) and run full selfcal routines.