hybridfree/eevblog-posts huggingface dataset:
Using Triac MOC3052 for ac load on/off - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: December 18, 2017, 06:49:31 am
content: 1. Have to turn on or off, ac load using micro-controller. Microcontroller is +5V powered.AC load is resisitive wire of 780ohms for heating wire purpose.2. using MOC3052, I am sending high & low on its anode, but output load dont get on/off.3. I am not using any zero cross here, I check when measured temperature is below setpoint just send +5V on MOC3052's anode & keep high until temperature is higher then setpoint then 0V on MOC3052's anode.Is it due to this, that MOC3052 dont get turn on or off, as I am not using zero cross?

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: December 18, 2017, 06:55:25 am
content: ckt

author: kripton2035
author_rank: Super Contributor
timestamp: December 18, 2017, 07:03:31 am
content: did you actually build the circuit ? if yes, then may be you don't have the MOC between A2 and G of the triac.something like this :
Using UCurrent to fix ships - Page 1
Forum section: electronics / beginners

author: Kiwi_Master_Chief
author_rank: Newbie
timestamp: March 12, 2018, 08:20:37 pm
content: All,Recently used a single UCurrent to datalog a -57 to 87 mA control signal concurrent with hydraulic pressure on a ship - what an absolutely great device better that helped immensely.Problem is we have two channels and we'd like two UCurrents to measure the backup channel. Where can I buy one? Any suggestions.Either way the UCurrent helped fix a problem that trips a 26,250 HP engine that had eluded a fix for 4 months.

author: tautech
author_rank: Super Contributor
timestamp: March 12, 2018, 08:26:45 pm
content: Welcome to the forum.Dave's online shop:https://www.eevblog.com/product/ucurrentgold/He's had some problems with an IC not performing as expected so until this issue is fixed there may be a wait for new stock.

author: Kiwi_Master_Chief
author_rank: Newbie
timestamp: March 12, 2018, 08:36:42 pm
content: Oh no worries glad to wait. Any chance he'll be adding a port for external power - had to leave it connected for a number of days. Also we would like to see the current shape a pulse off an accelerometer that is roughly 50 Pico coulombs /g of acceleration and is in the uA range by converting it to mV then scoping it. I'm wondering if that sounds like doable option (freq is < 10 KHZ)Thanks in advanceJim V
Using Voltage Divider to Make HV Measurements - Page 1
Forum section: electronics / beginners

author: eerocketman
author_rank: Contributor
timestamp: July 26, 2017, 03:43:17 am
content: Hi everyone!I was just wondering if I could use an RC filter at the output of voltage divider to reduce noise in the readings. I have attached the circuit I have in mind.Thanks,Ali

author: joeqsmith
author_rank: Super Contributor
timestamp: July 26, 2017, 03:55:50 am
content: 0805s?

author: eerocketman
author_rank: Contributor
timestamp: July 26, 2017, 04:00:30 am
content: Probably several 2512s in series, they were part of the symbol I'm using for resistors.

author: Zero999
author_rank: Super Contributor
timestamp: July 26, 2017, 09:03:41 am
content: It's a reasonable idea. Obviously not with 0805 parts. The voltage and power rating of both (especially the upper) resistor needs to be respected.Here's a link to a site which a handy calculator for selecting resistor values to use in a potential divider.http://sim.okawa-denshi.jp/en/teikokeisan.htmThere's no need for another resistor to make the RC filter. The output impedance of the potential divider is equal to both resistor value in parallel, so just choose a capacitor to give the required cut-off frequency.

author: perieanuo
author_rank: Frequent Contributor
timestamp: July 26, 2017, 12:56:46 pm
content: Yes hé can do it with 0805 or even smaller,just put 50-100 in seriesEnvoyé de mon iPad en utilisant Tapatalk
uSupply BASIC - Page 1
Forum section: electronics / beginners

author: newbie666
author_rank: Regular Contributor
timestamp: March 04, 2018, 11:10:57 pm
content: I've just finished watching a series of Dave's videos on uCurrent and I rather liked the "basic" version of the supply without uC. I decided to draw a schematic based on the video and design a PCB. Since these are my first steps with eagle / layout, please have a look at my PCB. I've done one ground pour on the bottom layer, is it a good idea or other grounding scheme would be preferred?A couple of questions about the PSU:* What should I do with LT1009 if I want to skip the trimmer? Should I just leave the ADJ pin unconnected?* I've checked most of the component ratings and I haven't found any reason this circuit wouldn't work up to 15V which would be useful for my audio projects. Am I missing something?

author: newbie666
author_rank: Regular Contributor
timestamp: March 05, 2018, 09:56:32 pm
content: OK, rev2:* fixed a feedback loop of voltage set opamp (was missing 2 resistors)* added optional resistor between voltage set pot and ground to be able to set minimum output voltage* changed connectors for outboard pots / ledAs always - any comments are more than welcome.

author: newbie666
author_rank: Regular Contributor
timestamp: March 06, 2018, 09:40:55 am
content: I've ordered boards at jlcpcb but I've submitted old gerbers with the bugI'll post some pictures when they arrive.

author: JS
author_rank: Frequent Contributor
timestamp: June 03, 2018, 05:59:02 pm
content: Too bad man, hope you can bodge that bug out...Did you received the boards?JS

author: kripton2035
author_rank: Super Contributor
timestamp: June 03, 2018, 06:02:18 pm
content: not sure a double side pcb was needed ?also it would like a ground plane too ?

author: JS
author_rank: Frequent Contributor
timestamp: June 03, 2018, 06:22:32 pm
content: I managed it in a single sided PCB, self etching friendly, with a differential opamp added for remote sensing, dual rails optional, no reference but a 5V regulator to feed the µC on an external board, and still some space for a decent ground plane on the same side. I plan to etch it today and probably test it during the week, I should start a topic on that after with all docs and info.JS
uSupply - Questions from beginner - Page 1
Forum section: electronics / beginners

author: StjepanV
author_rank: Newbie
timestamp: December 17, 2016, 01:15:52 pm
content: Hi there!I have a question that is bugging me about how uSupply works. It is basically linked to my general lack of knowledge about how linear regulator works.http://www.eevblog.com/files/uSupplyBenchRevB.pdfOn the rev B schematic we can see the C2 capacitor which, if understand it correctly, is there to be a decoupling capacitor for set voltage, right?But is there any feedback then from the output of the regulator to it's set pin? How is this circuit supposed to detect, for example, if there is a large draw of current and then if the voltage drops down, how is that compensated?Thanks in advance!

author: Kleinstein
author_rank: Super Contributor
timestamp: December 17, 2016, 02:08:02 pm
content: Voltage regulation is done only inside the LT3080. So it will compensate for changes in the input voltage, but not for the voltage drop that happens between the LT3080 and the output terminals.This circuit is not a good example to understand a linear regulator or a lab supply. Voltage regulation is kind of working, but current regulation is very slow.
uSupply understanding the lm358 common mode - Page 1
Forum section: electronics / beginners

author: hsn93
author_rank: Regular Contributor
timestamp: February 18, 2021, 07:27:21 am
content: hello, im looking at uSupply design :https://www.eevblog.com/files/uSupplyBenchRevC.pdfmy question is how LM358 (U12A) used to measure the voltage across high side sense resistors (1ohm) .. while it has input common mode (0 - V+-1.5) ..update: also the voltage swing .. i thought not all op amps can have output swing from rail to rail .. in this casefrom my understanding - datasheet output can go to 28v when its supplied with 30v

author: mvs
author_rank: Frequent Contributor
timestamp: February 18, 2021, 09:02:28 am
content: µSupply is an ongoing project and schematic is not final.Most dual opamps use same pinout and lm358 is often used as a placeholder during design phase.This allows you to trace and order a pcb before you decide which part you will actually use.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 18, 2021, 10:19:55 am
content: In the circuit U12A has indeed a problem with the common mode range. The LM358 is Ok at the negative rail, but not at all at the positive rail. In this case on can just skip U12A : the shunt part is low enough in impedance to directly drive the difference amplifier. The load adds some 36 K parallel to the shunt which would not be notices at all.The old µSupply design never really worked well and probably never will. It has a conceptional weakness in using a voltage regulator to building a lab supply. Adding current limiting to regulator that is not build with this in mind is a rather difficult task. It is usually easier to build the control loop for the lab supply from scratch without a regulator chip, which would only act as a relatively slow and poorly characterized power transistor, though with some basic thermal protection, which is about the only positive point about the regulator chips.

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2021, 10:31:10 am
content: The date on the schematic makes it nearly 9 years old. Is appears to be one of those hobby projects which got started, put to the back burner and forgotten.
ut210e beep diode hack? - Page 1
Forum section: electronics / beginners

author: smile
author_rank: Regular Contributor
timestamp: October 31, 2021, 09:32:22 pm
content: Hello, how do I make the ut210e beep in diode mode?

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: November 01, 2021, 07:19:25 pm
content: The UT-210 does not do that. It will just show the diode junction voltage. Typically between 0,5 and 0,8 Volt for silicon diodes. LEDs have more, depending on its colour. Old-school germanium diodes have less, about 0,3V.

author: smile
author_rank: Regular Contributor
timestamp: November 04, 2021, 10:22:04 am
content: Quote from: BreakingOhmsLaw on November 01, 2021, 07:19:25 pmI thought this model was hacked, even scope output was added. Is there no fix to beep on diode mode? checking diodes for short it's not nice to have to look at the LCD every time, sound indicator would be better.
UT210E still the one to buy? - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: February 28, 2021, 11:47:02 am
content: Is the UT210E still the best value for the money clamp meter if one is willing to reprogram the eeprom?

author: Gyro
author_rank: Super Contributor
timestamp: February 28, 2021, 11:52:06 am
content: I don't think there's actually any need to reprogram the eeprom as a 'condition' of purchase. Sure you can get increase the range counts, tweak the backlight etc. which is a nice to have, but it doesn't affect the fundamental sensitivity. I haven't bothered with mine yet and I'm quite happy with it as it stands.
UT210E - Page 1
Forum section: electronics / beginners

author: Kantilo
author_rank: Contributor
timestamp: September 25, 2021, 05:19:59 am
content: Hello, I received my UT210E, I wanted to do a test with the phone charging but it shows this, do you think it has a problem or did I do something wrong?Thank you

author: ataradov
author_rank: Super Contributor
timestamp: September 25, 2021, 05:51:45 am
content: It can't measure the current around both wires. You need to split the wire and measure the current only one way.Right now return current cancels out the consumed current.And accuracy on low DC currents may me iffy, despite what the documentation says.

author: Kantilo
author_rank: Contributor
timestamp: September 25, 2021, 06:02:50 am
content: I just tried it works thanks for your advice, can I take the measurements on the + and the - or is it better to choose the + ?

author: ataradov
author_rank: Super Contributor
timestamp: September 25, 2021, 06:29:26 am
content: Does not matter. You should get the same absolute value. The sign may be different, but it is also up to the orientation of the clamp.
UT501A for MOV testing? - Page 1
Forum section: electronics / beginners

author: ion
author_rank: Regular Contributor
timestamp: June 06, 2020, 10:16:19 am
content: After a power surge a few days ago my UPS blew a couple of power MOSFETS, which surprised me because it supposedly has decent surge protection.I suspect that it wasn't a huge surge seeing as nothing else on the same circuit was the slightest bit bothered, and the MOVs inside the UPS have probably just failed over the years.I was planning to pick up a UNI-T UT501A to test the MOVs in the UPS (and a few other surge protection devices). If I understand it correctly, the MOV should show open circuit (or close to it) at the lower voltages, and low resistance at the higher voltages.I'd appreciate confirmation that I got that right before I mess around with 1000V, and also that the UT501A is good enough for the job.It probably won't get too much use, so I couldn't justify a Megger.

author: retiredcaps
author_rank: Super Contributor
timestamp: June 06, 2020, 11:22:14 pm
content: Quote from: ion on June 06, 2020, 10:16:19 amA very simple test that I use to test MOVs (especially in used/abused multimeters from auction sites) is to see if they are open circuit or not using any multimeter.For example, if a MOVs shows 10M ohm on my multimeter, it's bad.BTW, it's cheaper just to order replacement MOVs if you suspect they are bad vs buying a UT501A unless you need that insulation meter on a regular basis.

author: ion
author_rank: Regular Contributor
timestamp: June 07, 2020, 10:09:49 am
content: I had actually tested with a multimeter a couple of months ago while tracking down an unrelated fault.The results were open circuit, all I could be sure of was that it hadn't failed short, but as I don't have a way to test it at high voltages, I can't be sure that it will work properly.True, a handful of MOVs are cheaper than the meter, but the prices on ebay aren't too bad, and I'd test more than just the UPS seeing as the surge protected plugs seem to have done nothing.Besides, if the MOVs test fine I'd need to look into what caused the substantial damage. I'm only 99% certain it was a power surge.
UTD2025CL DSO information request - Page 1
Forum section: electronics / beginners

author: mike_mike
author_rank: Super Contributor
timestamp: September 03, 2019, 12:24:49 pm
content: Hello, I have some concerns about a UNI-T UTD2025CL oscilloscope:1. Why there is more than 1 sine wave in the screenshots ? The screenshots show a TL431 regulator output. The coupling is set to AC, the trigger is set to CH1.2. While measuring output of a 50Hz 24Vac transformer, why the trigger notification on the DSO screen is switching fast between "Trig'd" and "Armed" ?
UTD2052CEX+ DSO from UNI-T - Page 1
Forum section: electronics / beginners

author: mike_mike
author_rank: Super Contributor
timestamp: October 23, 2024, 03:29:00 am
content: Hello. I think I made a mistake, because I found a UTD2052CEX+ DSO from UNI-T, and I bought it for about 250 USD. It is a 50MHz, 1Gs/s DSO. I need it to replace my old OWON SDS 1022 (Which is a 20Mhz DSO).I used it for a few hours, but I wanted to ask is this scope good for measuring in basic electronics circuits ?I also tried the UNI-T software on my PC and I liked it. It is simpler to save screenshots than using a USB drive memory stick.

author: BennoG
author_rank: Frequent Contributor
timestamp: October 23, 2024, 04:48:29 am
content: Why do you think you made a mistake.The new scope is better then the old one.Benno
Utility of a Bat85 diode in this particular circuit - Page 1
Forum section: electronics / beginners

author: Tito1337
author_rank: Newbie
timestamp: May 18, 2011, 10:46:40 pm
content: Hi everyone,I'm working on a circuit that takes a 0-15V pulse-width modulation signal and converts it to the same signal but in the 0-5V range. It's based on a 5V zener diode, which I understand quite well, but it has another diode, here is the schematic (sorry for French legend, MLI means PWM) :Does anybody understand the use of a Bat85 here? Thanks!

author: Unknown
author_rank: Unknown
timestamp: May 18, 2011, 11:17:28 pm
content: It looks like it has some sort of bidirectional function. The current path backwards is via a smaller resistance, possibly discharging or clamping something.You can use a simple divider to turn 0-15 to 0-5. My guess is that the input signal is an analogue signal 0-15V (not digital 0 or 15) then clamped at about 5V. What is connected around the circuit?

author: Rufus
author_rank: Super Contributor
timestamp: May 18, 2011, 11:24:56 pm
content: Without seeing the other circuitry either side it is hard to say.Basically the output PWM is driven high with +15v and 10k and driven low with 0v less a Schottky diode drop and 1k.Probably because the load on the output sources current and needs a low impedance drive which would be too low for the input PWM to drive at +15v or wastes too much power. You might want something like this if the output is driving an LS TTL input.It could also be to speed up the PWM falling edges.

author: Tito1337
author_rank: Newbie
timestamp: May 19, 2011, 12:21:30 am
content: The left part is connected to the PWM-generator (based on a LM311 comparator, 0 or 15V) and the right side to something like a relay controller (with two switches, one when input=0 and the other when input>0)So if I understand it right, it helps the output to fall faster to 0V than through the 10k ? Or it's standard circuitry before a relay controller ?
uuF feaad?  - Page 1
Forum section: electronics / beginners

author: heathkitman
author_rank: Contributor
timestamp: June 17, 2013, 03:15:16 pm
content: Some old schematic that I have been working with have capacitors marked in uuF.Is a uuF the same as a pF picofarad?Thanks

author: AlfBaz
author_rank: Super Contributor
timestamp: June 17, 2013, 03:43:43 pm
content: According to wiki micro, nano and pico were introduced in 1960, maybe micro was before pico

author: c4757p
author_rank: Super Contributor
timestamp: June 17, 2013, 03:45:37 pm
content: uuF is indeed equivalent to pF. uuF = micro-microfarad. micro=10-6, so 10-610-6F = 10-12F.

author: vk6zgo
author_rank: Super Contributor
timestamp: June 18, 2013, 02:15:31 pm
content: Quote from: AlfBaz on June 17, 2013, 03:43:43 pmwiki lies in its teeth!micro, & pico had been around for years before 1960.uuF were more 1930s & early '40s usage. (note the "u" is a printers best guess for the symbol "mu")I'm not sure when nanofarads were introduced in Europe,but I don't remember seeing them in any schematics in Australia before the mid 1970s---& that includes German ,Dutch & French equipment.

author: c4757p
author_rank: Super Contributor
timestamp: June 18, 2013, 03:11:44 pm
content: Quote from: vk6zgo on June 18, 2013, 02:15:31 pm1960 is when SI was introduced. My guess is that whoever wrote those articles couldn't find a citable resource for the first usage, so the date when they become "official" was listed instead.

author: jahonen
author_rank: Super Contributor
timestamp: June 18, 2013, 03:12:41 pm
content: Quote from: vk6zgo on June 18, 2013, 02:15:31 pmJust checked and found a Telefunken colour TV chassis service manual from 1971 (presumably). It seems to have nanofarads in the schematic. Couple of snapshots from schematic attached.Regards,Janne

author: vk6zgo
author_rank: Super Contributor
timestamp: June 19, 2013, 12:14:47 am
content: Quote from: jahonen on June 18, 2013, 03:12:41 pmThey can't seem to make up their minds in the first schematic---some of the caps are in decimal parts of a microfarad,& others in nF.In the '70s, the European TV/Broadcasting stuff I worked on,(LGT,Bosch/Fernseh,Philips,Rohde & Schwarz) would have been a few years old.Back when most components used in Australia were locally made,"point something uF" reigned supreme,except for Philips caps which used enormous numbers of pF on their first batch of Polyester caps.For instance,I still have some 10000pf Polyesters in my "Junk box" .

author: jebcom
author_rank: Regular Contributor
timestamp: June 19, 2013, 03:48:23 am
content: In the USA, micromicrofarads was still in common use well into the 1960's, and those books and publications were commonly available well into the 1970's. It takes a while to get people accustomed to new terminology. Sometimes I still have to think twice in order to get "nanofarads" out of my mouth, because when my brain was still pliable, it was either microfarads or picofarads.
UV-C Light wand hacking / IC Identification - Page 1
Forum section: electronics / beginners

author: Erwin
author_rank: Newbie
timestamp: March 28, 2013, 12:48:49 am
content: I could get a cheap UV-C Light wand (SG150 uv wand), and I thought that with some hacking I would be able to use it to erase EPROMs.It has 2 leds. When you connect power the red light turns on, you have to press the button for 3 seconds and the green led will start to blink. Press the button again and the green led will burn continuously AND the UV light will turn on for 30 seconds.This is not long enough, so I wanted to modify this device but it seems to contain some completely unmarked 8-pin IC. I did some measuring using my DMM and Scope.. and I think it's safe to say it's not a 555 timer or PICAXE. It uses a 0.9 MHz clock signal, contains some processing capabilities, and outputs a 95.2 KHz signal for 30 seconds when activated. Which in turn gets turned into some really high voltage. My DMM has a maximum of 600 volts and it showed 1100 / 1300 volts for 1 second before going into protection.If I know what IC this is, maybe I'm able to read it, modify the code and reprogram it to just output the 95.2 KHz signal whenever it has power, not even bothering about the pushbutton. Any ideas?EDIT: The bright red line on the board is +6 volts, the yellow line on the right is GND. The three small transistors are S8050 NPN transistors. The three larger ones (near the HV transformer) are D882 - NPN medium power transistors.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 28, 2013, 09:33:47 am
content: PIC12 series, probably PIC12F508

author: amyk
author_rank: Super Contributor
timestamp: March 28, 2013, 10:55:30 am
content: I've always wondered how helpful a search engine for IC pinouts would be...Beware the duty cycle of the power supply; it might not have been designed for continuous operation.

author: Erwin
author_rank: Newbie
timestamp: March 28, 2013, 11:22:10 am
content: Thanks Mike! O0Well.. I don't worry about the power supply, will connect it to my lab supply. Let's remove that chip and read it to see what I can do with it.

author: Erwin
author_rank: Newbie
timestamp: March 28, 2013, 09:13:39 pm
content: Ok, after several hours of trying, i'm not able to read this PIC12(?). I think it's either not a PIC, or it's protected.Anyway, currently looking for an other way to power the 4 watt UV-C tube, any suggestions (using components on the board?)
Uv erasers any good ones that don’t catch fire? - Page 1
Forum section: electronics / beginners

author: cypher007
author_rank: Contributor
timestamp: May 09, 2020, 10:57:04 pm
content: Are these ok?https://www.ebay.co.uk/itm/2994-High-Speed-Ultraviolet-UV-Light-Lamp-EPROM-Data-Eraser-Eraseable-Timer/264101136507?epid=25024510665&hash=item3d7da7887b:g:MF4AAOSwj81btziR

author: james_s
author_rank: Super Contributor
timestamp: May 09, 2020, 11:06:17 pm
content: They're cheaply made but they work fine. All of the cheap erasers you can buy are pretty much the same thing, a CFL ballast and a small germicidal tube. I wouldn't worry about them catching fire, but I would also not leave something like that plugged in unattended, there's no reason to.

author: richnormand
author_rank: Unknown
timestamp: May 10, 2020, 08:33:06 pm
content: I have one of those. Been working for 8 years. No issues.I glued a transparent plastic thumbtack (removed the pin) over the small hole in the drawer front.It glows a nice blue when the lamp is on.
UVC led manufacturer/supplier for 220nm wavelength - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 14, 2020, 07:22:56 am
content: looking for UVC led manufactuer who can supply 220nmwavelength.I searched almost all of them i found on alibaba but they are only lamp, etc manufacturer. Iam looking for leds manufacturer, need to make some custom design.I found was:https://www.alibaba.com/products/220nm_led.html?IndexArea=product_enhttps://www.banggood.in/buy/uv-220nm.htmlDoes anyone knows any reputed manufacturer?

author: RenThraysk
author_rank: Regular Contributor
timestamp: September 14, 2020, 01:59:41 pm
content: Not actually sure there is a commercial manufacturer of Far UVC leds.

author: mikerj
author_rank: Super Contributor
timestamp: September 14, 2020, 02:08:30 pm
content: There are no commercial 220nm LEDs, the crap sold on Aliexpress etc just lies about the wavelength since there has been lots of interest since COVID.
UVLO for multicell LiIon battery - Page 1
Forum section: electronics / beginners

author: rakeshm55
author_rank: Regular Contributor
timestamp: November 19, 2018, 06:39:18 pm
content: Hi,I plan to use 28V Liion battery to power my system. I wish to have UVLO feature implemented so that deep discharge of battery could be avoided..I expect UVLO to have threshold of 24V with a 2-2.5V hysteresis...By battery is connected to Push button controller LT2955 ... How to implement UVLO feature?? is there any standard circuit??please let me know....

author: mvs
author_rank: Frequent Contributor
timestamp: November 19, 2018, 07:08:23 pm
content: Quote from: rakeshm55 on November 19, 2018, 06:39:18 pmYou can use /KILL input to implement UVLO, just add voltage divider. Hysteresis will be 24*0.03/0.8=0.9V.

author: rakeshm55
author_rank: Regular Contributor
timestamp: November 20, 2018, 02:48:46 am
content: So for 512ms the device will remain on before kill triggers...I have about 400uF capacitor connected to this supply with inrush current limited to 3A....So this 3A for 30ms or about will it be a stress on battery ??....For rest of 512ms the board will be in the process of waking up OS...by this time power will be removed immediately ... Abruptly halting booting process ...

author: mvs
author_rank: Frequent Contributor
timestamp: November 20, 2018, 02:06:18 pm
content: Quote from: rakeshm55 on November 20, 2018, 02:48:46 amYou can use some voltage supervisor to block push button operation of LT2955 and send interrupt to your OS for graceful shutdown.PS At some stage it makes more sense to discard LT2955 and use low power 8-bit MCU to control custom requirements. You will probably need some sort of low level control also for charging, etc.
Uxcell components? - Page 1
Forum section: electronics / beginners

author: bitman
author_rank: Unknown
timestamp: September 28, 2018, 03:08:21 pm
content: Hey - I'm really not sure this is a good topic for "Beginners" but since that's what I am, I'll post here.On Amazon, AliExpress and a ton of other consumer shopping sites, if you search for basic electronic components like connectors, there's a very good chance you'll get some links with Uxcell stuff. They're usually priced reasonable for low quantity purchases. My question is how reliable these components are? I'm asking because I cannot find data sheets for any of the items, not even on Uxcell's own site. And I don't find their products on Mouser or Digikey.Here's an example:http://www.uxcell.com/20pcs-green-hg129508-terminals-pcb-mount-508mm-pitch-screw-terminal-barrier-blocks-300v-20a-p-671011.htmlhttps://www.aliexpress.com/item/20-Pcs-HG129-5-08-2Position-2Pin-5-08mm-Screw-Terminal-Barrier-Blocks-300V-20A/32341269123.htmlhttps://www.amazon.com/uxcell-HG129-5-08-5-08mm-Terminal-Barrier/dp/B00VG9BHB0When I look at similar screw terminals on Digikey, their ratings are only around 15A but I also have data-sheets that gives me complete dimensions and predicted performance etc. I feel like I'm missing something? Why would Uxcell not have data-sheets? Are their claims exaggerated or untested for the rating?Note, I've gotten a good deal of Uxcell in the past, and I've been happy with what I got. Not exactly the highest quality but for my peddling with electronics it's been good enough. But I'm getting to the point where I'm starting to doubt that I've made good decisions since I cannot find any materials covering the products they've offered. And since it's all over the web, with pretty much the same descriptions etc. I feel like I've been duped .... ?

author: ataradov
author_rank: Super Contributor
timestamp: September 28, 2018, 05:31:55 pm
content: A few things I've bought from Uxcell via Amazon were clearly not unique items. I assumed that Uxcell is just a reseller, not a manufacturer (even of white label stuff). They are not better than any random seller on eBay or AliExpress as far as I can tell.
V-1050F never used - Page 1
Forum section: electronics / beginners

author: Jwillis
author_rank: Super Contributor
timestamp: October 10, 2017, 06:27:55 pm
content: Hello I'm new to EEVblog.I recently purchased a Hitachi V-1050F that has never,as far as I can tell,been used or even plugged in.It's like band new.Even the probes and power cord are still in their packaging.The question I have is ,considering the age of the unit, if I should check all the electrolytic capacitors before I fire this thing up.Would hate to have it blow up because of an old cap.

author: edavid
author_rank: Super Contributor
timestamp: October 10, 2017, 06:44:47 pm
content: No, don't bother with that. It's much more likely that you would damage something yourself in the process of trying to test the capacitors.

author: danadak
author_rank: Super Contributor
timestamp: October 10, 2017, 09:12:35 pm
content: You might consider reforming the main power supply electrolytics.Just google "reform electrolytic", plenty of hits on how to.In old tube scopes common to use a variac and over a day pr two slowly bring up powersupply. In solid state scope this can backfire as some architectures want specific powerto come up at specific times, and faults will occur if that is not conformed to.Regards, Dana.

author: edavid
author_rank: Super Contributor
timestamp: October 10, 2017, 09:27:11 pm
content: Quote from: danadak on October 10, 2017, 09:12:35 pmI disagree. Just power it up and be done with it.

author: Jwillis
author_rank: Super Contributor
timestamp: October 10, 2017, 10:06:15 pm
content: It works perfectly! And it still has that new oscilloscope smell.Thankyou

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 12, 2017, 12:40:09 pm
content: If it ain't broke... don't fix it.

author: EEVblog
author_rank: Unknown
timestamp: October 12, 2017, 01:56:25 pm
content: Quote from: edavid on October 10, 2017, 09:27:11 pmYep, just stoke it up.

author: Brumby
author_rank: Unknown
timestamp: October 13, 2017, 02:07:30 am
content: Quote from: Jwillis on October 10, 2017, 10:06:15 pmI'm not surprised. I have a V-152B (circa 1980) which has, admittedly, been powered up every so often, but aside from a few bruises, it is still working well. I haven't checked the calibration, but the trace is as sharp as day 1.

author: james_s
author_rank: Super Contributor
timestamp: October 17, 2017, 07:43:44 pm
content: Yeah that's too new to worry about reforming capacitors. Even if one were bad, it's not likely to be shorted like the old waxed paper caps in antique radios.I love finding brand new old stuff like that.
V-lock battery plate Fotga ccUPS III 8.0V instead of 8.5V - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: August 10, 2017, 12:17:12 pm
content: I bought this battery adapter to have several V output from a V-mount battery: 14.8V, 12V, 8V, 5VThe problem is I have a GH5 and in the insertion it was written it is compatible: instead I discovered GH5 doesn't power up if Voltage is under 8,2V (battery at charged level), so it must be, externally, about 8.4-8.5V upto 9V...These are the pics of the board:(If you need more detailed pics, ask me, thank you.)Rough looking at it, do you think it's a good power circuit?Is it possible to modify the circuit to have 8,5V instead of 8V?EDIT:We are talking of this unit:https://www.amazon.com/Supply-System-Adapter-Charge-Battery/dp/B01B6011GO

author: willyfan
author_rank: Newbie
timestamp: August 10, 2017, 03:03:23 pm
content: I explained to you in another forum, but I replay here for forum users.You can change the SMD resistor R21 with a 7,8k new resistor. Code is 87B. I'm not sure what voltage you can have with this modification but I think that is around 8,7 - 8,9 volts. If you want have a better precision, you can put in the circuit a 5,2k resistor and a same value (5,2k) multi-turn trimmer series connected, so you can regulate voltage from (around) 6 to 11 volts.

author: Unknown
author_rank: Unknown
timestamp: August 10, 2017, 07:35:36 pm
content: I add here too, other detailed photos:http://imgur.com/a/AiYYFI tried with 7.5 kOhm (752) and the output Voltage became 8.5V: tested on GH5, it works perfectly!Thank you a lot for the suggestion.
v-reg ON|OFF control issue - Page 1
Forum section: electronics / beginners

author: mikes603
author_rank: Newbie
timestamp: December 09, 2013, 06:44:53 pm
content: I'm using a LM2576 switching v-reg that has a ON|OFF port. Which, of course, looks for a high to go off. Now, I'm sending out a 200ms long pulse from my uC (powered from my bench supply so there is no race condition issue). And, looking at the uC output pin with my scope I see that there is in fact a nice (no skew) 200ms pulse.My issue is when I tie that uC output into my v-regs ON|OFF pin. Once the uC output is wired to the v-reg signal input I no longer see a 200ms pulse, but a short 35ms pulse with skew.Any idea what is going on here? My v-reg isn't being pulled down enough because it's only getting that short blip instead of the full 200ms I'm generating.

author: fcb
author_rank: Super Contributor
timestamp: December 09, 2013, 10:52:52 pm
content: Please post a diagram or sketch. Much quicker for us to understand.

author: mikes603
author_rank: Newbie
timestamp: December 10, 2013, 12:49:43 am
content: Quote from: fcb on December 09, 2013, 10:52:52 pmI'm only running Vin at 5.5v temporarily (I know that's low) so I can run the uC off it and avoid the possibility of a race condition causing my issue.Excuse my DoodleCAD

author: mikes603
author_rank: Newbie
timestamp: December 10, 2013, 01:06:08 am
content: Quote from: AcHmed99 on December 09, 2013, 11:06:17 pmThat's probably it. The v-regs signal input probably isn't as low Z as i assumed. I'll give a pull-up a go. Thanks.
v-reg shutdown by uC, best method? - Page 1
Forum section: electronics / beginners

author: mikes603
author_rank: Newbie
timestamp: December 02, 2013, 02:42:17 pm
content: Trying to use a digital pin on an Atmega328 to reboot the uC by bringing the ON/OFF port on a v-reg high. It works, however, I'm concerned that the HIGH is only long enough to bring V-out down to only 2.8v and for only 38ms. And that this might not fully cycle all my ICs on that VCC bus. What's the best way to do this?

author: fmaimon
author_rank: Unknown
timestamp: December 02, 2013, 04:02:30 pm
content: If you want to do your way, a 555 in a monostable configuration? The uC triggers it and it stays on for as long as you program it.You can also wire the output directly to the reset pin.The other (better) option is to use the watchdog timer to do it. If you want to reset, just start an infinite loop that don't reset the timer.

author: mikes603
author_rank: Newbie
timestamp: December 02, 2013, 05:11:40 pm
content: Well I want to shutdown the v-reg not just bring the uC into reset. As I have other ICs (I2Cs) I want power cycled. A 555 had crossed my mind, but what's the part count? I was concerned it would be 5 or so parts.

author: kripton2035
author_rank: Super Contributor
timestamp: December 02, 2013, 05:28:06 pm
content: use some voltage regulator and sequencer like this one ?http://www.maximintegrated.com/datasheet/index.mvp/id/2484

author: mikes603
author_rank: Newbie
timestamp: December 02, 2013, 06:46:48 pm
content: Well, I already have a box of LM2576s I need to use for this device. I'll keep that v-reg in mind in the future.For now I'm looking at:http://www.st.com/st-web-ui/static/active/cn/resource/technical/document/application_note/CD00059552.pdfIt's for monitoring a threshold VCC. But it also has a RST pin for a button. This (STM812) might work for me if I tie a digital out from the uC into it. And it's 1 part at $0.70ea.

author: kripton2035
author_rank: Super Contributor
timestamp: December 02, 2013, 07:52:39 pm
content: then a monostable circuit like the one on this page :http://www.electronics-tutorials.ws/sequential/seq_3.htmlusing a small gate circuit from texas like this one :http://www.ti.com/product/sn74auc2g00and a resistor and a capacitor.

author: mikes603
author_rank: Newbie
timestamp: December 02, 2013, 09:15:15 pm
content: Perfect. Thank you!

author: mikes603
author_rank: Newbie
timestamp: December 02, 2013, 10:16:07 pm
content: Is there a 5volt version of that SN74AUC2G00?

author: sdg
author_rank: Regular Contributor
timestamp: December 02, 2013, 10:46:00 pm
content: Quote from: mikes603 on December 02, 2013, 10:16:07 pm74LVC1Gxx (1.65-5.5v), 74AHC1Gxx (2.0-5.5v), 74AHCT1Gxx (5v)
vA rating of toroidal transformer to amps available on secondaries? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 14, 2014, 10:55:00 am
content: I have a toroidal transformer that I know has 2 secondary windings of 17.5V each. It is rated as a 160vA transformerThe primaries are two split windings of 120V each. Now, I think I need to divide the vA rating by the secondary voltage, but with 2 secondary windings of 17.5V each, do I divide by 17.5 or by 35.0?I think it can either supply 9 Amps per secondary winding, or 4.57 Amps. Not sure which....Thanks.

author: electronics man
author_rank: Frequent Contributor
timestamp: April 14, 2014, 11:25:11 am
content: It depends how you have them configured if you have the secondaries In series then it's 35.0 but if you have them in parallel then it can provide 9amps but if you are using them separately then it is 4.57 amps each (providing your numbers are correct)

author: mariush
author_rank: Super Contributor
timestamp: April 14, 2014, 01:51:45 pm
content: No matter how you connect the secondaries, you still have 160 VA.In parallel, you have 17.5v ... so 9 A .. In series you have 35v and 4.5ABut note that when you rectify this AC to DC using a bridge rectifier, you get a peak dc voltage of about 1.414 x Vac (square root of 2 times ac voltage).So with 17.5v AC you get 24.75v , with 35v you get a peak of 49.5v ... and the transformer can still do only 160va ... so in theory the DC current will be 160/24.75 = 6.46a or 160/49.5 = 3.23aIn practice, due to losses in the bridge rectifier itself the formula Idc = 0.68 x Iac is more accurate ... so you'd have 24.5 peak dc voltage and 0.68x9 = ~ 6.1A , or 49.5 peak dc voltage and 3.06A

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 14, 2014, 02:01:42 pm
content: Thank you Electronics man and Mariush, much appreciated. I got this transformer at a rally as circa 24V and 50V are useful supplies after a bridge rectifier, for a couple of future projects. I see how the VA rating works now, and how it remains the same with series or paralleled outputs, cheers.
Vacuum tube ok or not? - Page 1
Forum section: electronics / beginners

author: Simon123
author_rank: Regular Contributor
timestamp: November 16, 2013, 10:42:35 pm
content: Hello!I have gm5606 philips cro, and after looking ate the symphtoms i found one of these tubes is defective-left i think.But i am not shure, it works just so there are voltages on the output, but it acts unstable, if i switch em aroun the other part of the circuit doesnt work.So its little bit white on the top?

author: G7PSK
author_rank: Super Contributor
timestamp: November 16, 2013, 10:49:02 pm
content: White on top usualy means that some air has leaked into the valve/tube. Check the filiment if not burnt out now it soon will be.

author: AF6LJ
author_rank: Unknown
timestamp: November 16, 2013, 10:56:05 pm
content: As the poster above indicated the white on top indicates that gas is present in the tube.Get another tube.

author: SeanB
author_rank: Super Contributor
timestamp: November 17, 2013, 03:36:34 am
content: It still has a good vacuum, but likely the heaters have lost emission and this means end of life. You can rejuvenate the heaters if you do not have another but best is to replace it with a NOS one.

author: Simon123
author_rank: Regular Contributor
timestamp: November 17, 2013, 09:38:19 am
content: Ok, thanks ill proably buy new one.
Vacuum tubes - Page 1
Forum section: electronics / beginners

author: Simon123
author_rank: Regular Contributor
timestamp: November 02, 2014, 12:35:14 am
content: Hello!I wonder how are called those screw type socket (like lightbulb vacuum tubes).They have ball shaped envelope and components are horizontal.I think they were made by philips but i'm not shure.Thanks

author: atferrari
author_rank: Frequent Contributor
timestamp: November 02, 2014, 01:25:17 pm
content: Any picture that you could show?

author: Simon123
author_rank: Regular Contributor
timestamp: November 02, 2014, 02:33:28 pm
content: Yeahttp://media-cache-ec0.pinimg.com/236x/39/68/3b/39683b0cd2633c21090eaf3fa8ae8f8c.jpglike that but screw socketIm actualy searching a website(i lost link), that had nice explanation of triode and cutoff showing internals

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: November 02, 2014, 02:48:55 pm
content: Quote from: Simon123 on November 02, 2014, 02:33:28 pmHi.That looks like anR-Typeto me and the screw socket is probably anEdison

author: Simon123
author_rank: Regular Contributor
timestamp: November 04, 2014, 07:37:54 pm
content: Thanks!

author: vk6zgo
author_rank: Super Contributor
timestamp: November 05, 2014, 05:48:17 am
content: I'm very dubious about there ever beingvacuumtubes in such a configuration.There aren't enough connections for a triode,or even a vacuum diode.I have seen gas filled rectifiers in a similar package.The particular kind I knew were called "Tungar" rectifiers,& were often used in battery chargers.They didn't use a thermionic cathode,so only needed the two connections available with an Edison screw base.I take it all back about the Tungar---theydidhave a filament & a separate anode,
Vagal Tone Vagus Nerve HRV = instant relaxation - Page 1
Forum section: electronics / beginners

author: Samuel_Tychy
author_rank: Newbie
timestamp: November 08, 2017, 01:37:07 pm
content: Hello to you all I would like to point your attention to simple yet very effective way to achieve relaxation its called Heart Rate Variability and this little gadget helps in traininghttps://plus.google.com/u/0/photos/photo/103609195258896881522/6486033918363993074?icm=false&iso=true&authkey=CP-Hz_WJz_fDRgCode:int PWMPin = 11; //ARDUINO PWM OUTPUT PINvoid setup() {}void loop() {for (int INTENValue = 255 ; INTENValue >= 40; INTENValue -=1 )//FOR LOOP FOR LOOPING THE VALUE of INTENSITY{analogWrite(PWMPin, INTENValue);//THE VIBRATION INTENSITYdelay(26);//DELAY FOR ACHIVING 5 seconds but 5.5 is actually better}}it's all about Diaphragmatic breathing

author: Simon
author_rank: Unknown
timestamp: November 10, 2017, 09:22:14 am
content: Well don't expect anyone to take it seriously......, oh and far from technical, I'll move it to beginners.....

author: orolo
author_rank: Frequent Contributor
timestamp: November 11, 2017, 11:17:55 am
content: A bit hard to tell from the image, but is that protection diode backwards? Blue wire comes from the emitter of the NPN, goes into pink envelope, and comes at the other side into theanodeof the diode.Edit: probably it's the collector cable that goes into the envelope, after changing color just when crossing the emitter cable, and emitter is grounded. Then the circuit is ok, but the image is confusing.
Vaio BPS26 Repair Component Required - Page 1
Forum section: electronics / beginners

author: sadat
author_rank: Newbie
timestamp: April 22, 2018, 10:45:13 pm
content: Hi All,New here and first post as well!I am in the process of repairing/reviving my 6 year old Sony Vaio SVE1511Q1EB which is pretty much useless at this point. So after spending some time online I opened up my BPS26 battery to replace the cells with some new ones, but encountered some issues right off the bat. While disassembling the outer case of the battery, few diodes from the controller PCB were pretty much glued with the outer case and ripped off!I have attached pictures to this post of the PCB and the diode components. The problem now is that I don't have a schematic nor do I know the exact diode types.Here are the diode deatils and electrical measurements using my DMM:Markings: "A0"Forward Voltage Drop: 0.749VForward Resistance: ~8 M ohms (yes quite high!)Reverse Resistance: OLForward Capacitance: 0.045nFPackage: SOD 323 (2 pin) I think!Multimeter: Kasuntest ZT102I have also looked at similar threads like this one:https://www.eevblog.com/forum/repair/sony-vaio-repair-battery-pinout-needed/. The motherboard schematic (for my model) doesn't help as this PCB is inside the battery so I need a schemtic for that PCB is its even there! I tried searching for it but with no luck.Any inputs with the diode, schematic or other suggestions are welcome.-Sadat

author: sadat
author_rank: Newbie
timestamp: April 22, 2018, 10:46:35 pm
content: More pictures of the board added.

author: sadat
author_rank: Newbie
timestamp: April 22, 2018, 11:08:23 pm
content: picture attached with the some of the routes I traced so far.

author: tahirmaqsood
author_rank: Newbie
timestamp: May 25, 2024, 04:41:56 am
content: plz bps26 schematic diagram upload
valentine card - Page 1
Forum section: electronics / beginners

author: Munyua44
author_rank: Contributor
timestamp: January 17, 2022, 04:35:15 am
content: i want to do a valentine card for my girlfriend. The card should be in PCB form and very attractive. I think of doing it on KICAD EDA and share the schematic with any fab house for production. Is KICAD the best? which fab house is the best? and how can i make this possible?attached is the sample of what I need to do:https://www.pcbway.com/project/shareproject/Rudolph_the_Red_Christmas_IOT_Card_fdf2904b.html

author: ledtester
author_rank: Super Contributor
timestamp: January 17, 2022, 05:21:53 am
content: Quote from: barycentric on January 17, 2022, 05:04:35 amand _when_ you need it.February 14th is less than a month away... might want to have a back-up plan in case your board order is delayed.

author: SeanB
author_rank: Super Contributor
timestamp: January 17, 2022, 09:35:11 am
content: Chines New year is very close, so your only option is do it fast, and pay for expedited delivery by courier as well, because if it is going regular post or regular courier it will only be arriving in mid to late March.

author: rpiloverbd
author_rank: Regular Contributor
timestamp: January 18, 2022, 01:04:49 pm
content: You can contact JLCPCB or Rayming PCB.

author: themadhippy
author_rank: Super Contributor
timestamp: January 18, 2022, 01:18:20 pm
content: By the time youve bought the pcb and components you might as well save time and hassle and buy a kithttps://quasarelectronics.co.uk/Item/velleman-mk101-flashing-led-sweetheart-kit

author: MK14
author_rank: Super Contributor
timestamp: January 18, 2022, 01:20:11 pm
content: Warning: OP has been banned.

author: magic
author_rank: Super Contributor
timestamp: January 19, 2022, 07:33:38 am
content: Quote from: barycentric on January 19, 2022, 07:12:17 amYep, the dead face under the username.Also, miraculously stopped posting new threads with the same questionsQuote from: barycentric on January 19, 2022, 07:12:17 amAnd that was probably the reason for the ban - I have reported that guy on the grounds of similar suspicions.

author: Bud
author_rank: Super Contributor
timestamp: January 19, 2022, 07:50:09 am
content: Valentine PCB card with Christmas Rudolf theme for girlfriend , what can possibly go wrong ?