hybridfree/eevblog-posts huggingface dataset:
2 questions about flux - Page 1
Forum section: electronics / beginners

author: apelly
author_rank: Unknown
timestamp: October 15, 2013, 09:01:06 pm
content: 1) For my whole life, and for the first half of my current spool of solder, flux residue has been brown and fairly minimal. Now it's green, gunky and plentiful. Is this due to soldering at a lower temperature? I'm around 330C at the moment.2) What do you guys use to clean this up? Acetone works, but makes the solder mask sticky. Any suggestions?Aaron.

author: Alex
author_rank: Regular Contributor
timestamp: October 15, 2013, 09:34:00 pm
content: Regarding #2, you can try isopropyl alcohol (IPA) or a purpose-made flux remover (eg. Electrolube LFFR).Alex.

author: deth502
author_rank: Frequent Contributor
timestamp: October 15, 2013, 10:09:25 pm
content: +1 to alex. ive used the flux remover spray before and it works great. i just dont do large enough jobs for me to justify buy it again. if i do a repair with a few joints, or a small project, i just scrape the heavy flux with a pick and brush the board. but yeah, if youve got a large board to clean, the spray is the only way to go.

author: mcinque
author_rank: Unknown
timestamp: October 15, 2013, 10:39:13 pm
content: Quote from: apelly on October 15, 2013, 09:01:06 pmTrichlorethylene. Cheap, well tolerated by solder mask and components, works very very well for me, and it doesn't leaves residues at all.

author: nanofrog
author_rank: Super Contributor
timestamp: October 15, 2013, 11:25:25 pm
content: +1 toAlexanddeth502.Quote from: mcinque on October 15, 2013, 10:39:13 pmWorks well, but likely hard to get now (carcinogenic & environmental concerns).

author: apelly
author_rank: Unknown
timestamp: October 15, 2013, 11:59:13 pm
content: IPA it is. Thanks guys.I'd still like to know what's up with the green flux though. Soldering leaded onto lead free tinned pads? Seems unlikely. PCBs are coated with nickel aren’t they?

author: kizzap
author_rank: Unknown
timestamp: October 16, 2013, 12:13:44 am
content: Are you saying that the flux changed colours half way through the roll of solder? are you perchance working on new boards that you haven't used before?The only other option I can think of is that the solder manufacturer changed their flux recipe half way through a cycle and it just so happened to change in your roll.-kizzap

author: apelly
author_rank: Unknown
timestamp: October 16, 2013, 12:48:11 am
content: Quote from: kizzap on October 16, 2013, 12:13:44 amYes and yes. Haven't tried going back to something I've worked on before. Will do.Quote from: kizzap on October 16, 2013, 12:13:44 amSeems pretty unlikely.Aaron.
2 questions, no relation - Page 1
Forum section: electronics / beginners

author: DoublesAdvocate
author_rank: Newbie
timestamp: May 03, 2023, 01:07:52 pm
content: I have a few broken PS3's (CECH-4XXX) that refuse to read discs. After a bit of google and some prodding with a multimeter I've determined that one of the little SMD fuses near the drive circuitry has blown. I'd love to replace it and get the consoles reading again but I have no idea what the value(s) of the fuse is as there aren't any markings on the fuse or board and (obviously) there are no repair manuals or documentation for the device online. Does anyone know of a way that I can determine the value of the fuse? I do have a donor board where I can test a working version of the fuse, but it also has no markings so I'm at a loss for HOW to actually test it, suggestions?Question #2 is:I'm trying to build a passive headphone/mic mixer and would like some sort of switch that can swap the function of 2 pins on a TRRS connector so it can support both common microphone wiring configurations. Does anyone have any suggestions for what type of switch I can use for this?

author: wasedadoc
author_rank: Super Contributor
timestamp: May 03, 2023, 03:05:09 pm
content: Quote from: DoublesAdvocate on May 03, 2023, 01:07:52 pmIf the fuse is the only problem on the broken board you can measure the current that normally flows through it by bridging it with a multimeter set to measure current. Start with the 10A range or whatever is in that ballpark. If the PS3 then reads discs note the highest current and get a fuse say 50% higher than that.

author: themadhippy
author_rank: Super Contributor
timestamp: May 03, 2023, 03:38:15 pm
content: QuoteA red one?seriously, more info needed of what your trying to achieve would be useful,

author: wasedadoc
author_rank: Super Contributor
timestamp: May 03, 2023, 04:17:07 pm
content: Quote from: DoublesAdvocate on May 03, 2023, 01:07:52 pmDPDT

author: DoublesAdvocate
author_rank: Newbie
timestamp: May 03, 2023, 10:09:48 pm
content: Quote from: themadhippy on May 03, 2023, 03:38:15 pmSorry yeah I think what wasedadoc suggested is what I'm looking for.Basically there are 2 common wiring configurations for headphones, CTIA and OMTP. The wiring they use for the output of sound/music is the same between them but the configuration for inline microphones swap poles and I'm trying to build a circuit that you can select manually rather than having to rely on detection circuits.(not sure if I embedded that correctly)Quote from: wasedadoc on May 03, 2023, 03:05:09 pmOkay perfect, I'll give that a shot.
2 RPi Zero W to 1 SPI 2.8" monitor - Page 1
Forum section: electronics / beginners

author: antolanca
author_rank: Contributor
timestamp: December 08, 2018, 08:52:13 pm
content: Hello everyone. I'm wanting to build a visor using 4 Raspberry Pi Zero W, 4 cameras (2 IR, 2 Thermal) and 2 monitors smaller than 3" each. However, all monitors I can find below that size are all connected in SPI instead of HDMI. Now the Pi has only one camera input hence why using one per camera (I can use usb but then would lose FPS which is important on a visor. At least it's what I've read online) and I am happy to use the SPI connections.However, so far no one has been able to explain to me as to how can you connect a switch in order to switch from displaying Pi 1 to displaying Pi 2.And even Youtube videos explaining how SPI works don't actually give me any ideas as to how can I switch from one to the other.If anyone could explain to me how it actually works and how can I switch from one to the other (in very lay man terms please) I would very much appreciate it.Thanks in advance.

author: ogden
author_rank: Super Contributor
timestamp: December 08, 2018, 09:04:13 pm
content: Forget about SPI display it is slow. Search resulted in <3" RPi display, so they exist. You just have to search them:https://thepihut.com/collections/raspberry-pi-screens/products/adafruit-pitft-2-8-touchscreen-for-the-raspberry-pi

author: antolanca
author_rank: Contributor
timestamp: December 08, 2018, 09:53:29 pm
content: That display uses SPI."The plate uses the high speed SPI interface on the Pi and can use the mini display as a console, X window port, displaying images or video etc. Best of all it plugs right in on top!The plate uses the high speed SPI interface on the Pi and can use the mini display as a console, X window port, displaying images or video etc. Best of all it plugs right in on top!"But what I actually need is a switch.

author: tsman
author_rank: Frequent Contributor
timestamp: December 08, 2018, 10:03:51 pm
content: You say "2 IR, 2 Thermal" but there isn't a thermal camera module that is compatible with the CSI interface on a RPi so you're down to only two cameras across two RPi Zero boards. If you're using the NoIR RPi camera then be aware that the colours for some things are all messed up since it is lacking the IR cut filter.

author: ogden
author_rank: Super Contributor
timestamp: December 08, 2018, 11:07:51 pm
content: Quote from: antolanca on December 08, 2018, 09:53:29 pmOuch, how did I miss that. Sorry. I thought that all their displays haveDPI interface

author: Kasper
author_rank: Frequent Contributor
timestamp: December 09, 2018, 06:23:08 am
content: Quote from: tsman on December 08, 2018, 10:03:51 pmIts easy to add a switchable IR cut filter.Google 'ir cut filter switch'And should probably get an illumination sensor too so you know when to switch the switch.And maybe some IR LEDs too but be careful with those, they can be high enough power to damage eyes while not being visible.
2 SPDT switch to control a lamp in 2 different locations - Page 1
Forum section: electronics / beginners

author: joersam24
author_rank: Contributor
timestamp: June 12, 2012, 03:23:27 pm
content: hi to all,Can anyone show the wiring diagram of 2 SPDT switch that can switch on and off a lamp independently in two separate locations? Thanks...

author: deephaven
author_rank: Frequent Contributor
timestamp: June 12, 2012, 03:49:07 pm
content: Do you mean two switches? If so, this:
2 Stage Preamp gate not closing - Page 1
Forum section: electronics / beginners

author: blewisjr
author_rank: Frequent Contributor
timestamp: October 08, 2013, 02:28:42 pm
content: Ok so I came across a new issue while trying to get more sensitivity on my Electret Mic LED trigger circuit.To get more sensitivity as it really was not sensitive enough to get solid triggers from a distance I decided to add a second preamp stage.So now I have a 2x NPN3904 preamp before the signal gets to the micro. It is now sensitive and I can actually trigger it off with my voice from a few feet away. +1 for the second stage.The issue I have now is that the gates are staying open leaving the led lit when they should close back off.Here is the circuit diagram of the whole setup attached.What would I have to do to get the gates to close. Would 10k resistors from the emitters to ground get the current to drop?Edit: Never Mind I was able to fix the problem after a crap load of experimenting. Turns out there was not enough Gain on the second stage. By replacing R5 with a 6.8k resistor and adding a 10k resistor from ground to the output capacitor everything started functioning properly.
2-wire thermostat / controller - Page 1
Forum section: electronics / beginners

author: brainwash
author_rank: Frequent Contributor
timestamp: January 09, 2017, 02:27:16 pm
content: I live in a rented apartment so cannot modify a lot of stuff. I have electrical heating with two analog thermostats. These have a bimetal strip that close a 220V contact that triggers remotely a big relay (something like 480V / 16A). The current that flows in that thermostat while closed is around 20-50mA. Might be 100-200mA, it's been a while since I've measured it.There is no null connection, just two wires.My goals are: be able to remotely start/stop the heating, set the temperature digitally, measure how long the contacts stay closed (for power consumption, the heating runs at full power when on). It's doesn't need to react instantly, I think 1-2 minutes is fine.I don't know if there are similar modules on the market so I was thinking maybe I could parasitically power some RF module that does the job for me. An ESP8266 + triac/ssr would work nicely but it has the issue of power consumption. So perhaps either power it from some batteries for a while and see if the idea works or use a lower-power RF module.I don't know if the ESP8266 can be held in low-power and with WiFi off while it measures stuff and wake up once every two minutes or so. I'm saying ESP8266 because it has both the RF transceiver and the uC integrated.Just thinking out loud.

author: Seekonk
author_rank: Super Contributor
timestamp: January 09, 2017, 03:22:59 pm
content: This might be worth looking at sourceforge.net/p/opentrv/code-0/HEAD/tree/trunk/Arduino/V0p2_Main/

author: brainwash
author_rank: Frequent Contributor
timestamp: January 09, 2017, 03:34:37 pm
content: Looks interesting but I'm targeting a different use-case. There's a slew of valve controllers on the market, I'm pasting links from amazon.de but just to show the products are already there:https://www.amazon.de/SmartBlue-Heizköperthermostat-Bluetooth-Programmierung-Smartphone/dp/B0168RN8ZW/The innovative thing is the occupancy sensor but it's not applicable to me.Meanwhile, I'm looking for a replacement for one of these, in the same format:https://www.amazon.de/Eberle-Raumregler-RTR-GradC-111110151100/dp/B0014DOH0QOr, some module I can build myself and attach to the existing one. I would set the cutoff at the main contacts to 30C and use my addon to control the heating.Or if something similar (same format) exists with RF control, I can intercept the signals, that can also work for me.
20 x 4 LCD Extra Component Pads - Page 1
Forum section: electronics / beginners

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 28, 2021, 11:23:19 pm
content: Anyone know what the extra device pads are for on the back of 20 x 4 LCD displays. I look for diagrams and data sheets, but all I get is Arduino connections.

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2021, 11:37:35 pm
content: Not sure about C1/C2, but the rest is for adding an ICL7660 charge pump IC to generate negative voltage for the LCD biasing. It’s needed for 3.3V operation, or for some LCD panel types like some extended-temperature or jumbo-size ones. (In essence, the contrast voltage sometimes needs to be more than 3.3V lower than Vcc. If you’re running it on 5V, and you need, say, 4V less, then you’re still at +1V, but at 3.3V, you’d need to go to -0.7V, thus requiring a negative supply.)

author: amyk
author_rank: Super Contributor
timestamp: December 29, 2021, 01:28:53 am
content: C1 and C2 are for additional decoupling, which they decided wasn't necessary in this case.Quote from: Ground_Loop on December 28, 2021, 11:23:19 pmAdding -arduino will usually remove most of that crap.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 29, 2021, 03:01:54 am
content: Thanks for the replies. I had a feeling about C1 and C2, but the charge pump was unexpected.
200A PWM controller intermittent problems - Page 1
Forum section: electronics / beginners

author: andidan
author_rank: Newbie
timestamp: July 03, 2024, 06:42:59 pm
content: So I got these two unnecessarily huge 200A PWM speed controllers. ($85 each, see my part overview here -).Details:Using on a 55lb thrust trolling motor that uses max 50 amps. I oversized because I had a PWM quit on me 2 miles from the boat ramp and had to paddle. I assumed these were safe because of sheer size/Amperage.Using DC House 100Ah LiFepPO4 battery. Battery not the problem. Hooked the trolling motor directly, no issues.The PWM is in a box that has 2 exhaust fans on it. I have a temp probe in the box and it was max 33C with 31 ambient. Plus it has 2 fans on the MOSFETs heatsink.Barley getting warm at 50A continuous. I tested with a 12v heater that pulled 48A for an hr continuously. No problem.Problem - both PWM's have this weird problem: 3 out of 10 times, when I "accelerate" by rotating the pot, the current will shut off and restart in a second. And shut off and restart. At one point it did it 5 times in row. Could happen at 20A or at 40A. Then it works fine, once it's set on power, even if it's max. I managed to replicate it on the bench using 2 10A pumps. It's like a glitch - stop and restart almost immediately. On a boat you feel it. It's like braking abruptly and accelerating immediately.What I did:I changed the pot, changed the Fwd/Rev switch, checked all connections and wiring, and finally I checked with a smaller PWM (the small one in the video). Problem solved. Went all day on the lake, problem never appeared again. But I don't trust the small one because it warms up with continuous use.The board has 2 MOSFETS for FWD and 2 for reverse, HY4008, rated at 200A. Also a relay for each direction rated at 200A. There are also 2 Schottky diodes, 1 for each channel, MBR30100PT. The diodes are rated at 30A. The problem occurs ONLY during acceleration, when there's a spike in Amps, and it's definitely over 30A. Thinking diodes are undersized, I replaced the 2 diodes with 60A equivalent (MBR60100PT), but the problem persists.Now, is there any idea out there about what part of the PWM could create that current drop/restart? It would be a shame to throw away 2 potentially good industrial size PWM's if maybe there's a simple fix. I'm in contact with seller to get refunded, given the steep price. Thanks!

author: m k
author_rank: Super Contributor
timestamp: July 14, 2024, 05:40:20 pm
content: It can be a program error of a PWM controller, but then it must be always there.If its style is intermittent it most likely is a contact problem.But it can also be inside a component.The problem component doesn't need to be big.It can also be an overcurrent feedback something, like a small resistor.
200Vac power supply on 230Vac - Page 1
Forum section: electronics / beginners

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: December 10, 2017, 05:06:16 am
content: I recently purchase a Takasago SX020-100 DC power supply on ebay and the name plate mentions 200Vac (not sure what the frequency is), the mains power in my part of the world is 230V, 50Hz. I am planning to connect a transformer 230V / 12 V transformer in series with the mains input of the DC power supply in subtractive mode that is I will connect the 12 V secondary in series with the mains input of the power supply and then power up the 230V primary of the transformer that way I expect 230 - 12 = 218V to be present on the input of the dc power supply.Even this seems to be beyond the rating of the japanese power supply so I thought why no wire up 2 transformer s in series so that makes it 230 - 24 = 206V.Is this a right approach to reduce voltages or is there a better one? The DC power supply is rated at 0 to 20V, 100A, so that makes it a 2000W power supply. But initially I don't intent to use it at full power.

author: Seekonk
author_rank: Super Contributor
timestamp: December 10, 2017, 07:52:04 am
content: If you can pick it up, it is likely a switching power supply and it won't care. I would pop the top off and look at the voltage rating of the caps to see if the peak voltage of the mains is less than the capacitor rating with some margin. I take it you didn't go with 24V because you have this one in your bin.

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: December 10, 2017, 08:12:39 am
content: Quote from: Seekonk on December 10, 2017, 07:52:04 amYes its a swtching power supply and its in warranty. I contacted the seller and they said theey tested it upto 240Vac I hope they have not damaged the power supply. Yes I have some 12V, 20A trafos with me and now I intend to use 3 of them in seriese

author: amyk
author_rank: Super Contributor
timestamp: December 10, 2017, 05:22:44 pm
content: The name sounds Japanese, and thus 200V makes sense since their usual mains is at 100V instead of the more common 115/117/120. You would have to look carefully at the input circuitry to make sure no components are too close to their ratings, but I have had no problems running Japanese 100V devices on 120V.

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: December 10, 2017, 05:38:25 pm
content: Quote from: amyk on December 10, 2017, 05:22:44 pmYes this is a Japanese power supply.I have looked at the other models on their website and they have few power supplies 100V ac rated and few 200V ac rated +/-10%, and even few more with a wide power supply range. So most likely this could be 200Vac +/-10%. Currently I have put 2 12V secondarys in series with the input and the voltmeter shows around 200Vac at the input of the power supply so for now I'm good to go, My only concern is the ebay guys have tested the power supply @ 240Vac hopefully its not damaged any components while doing so.
2014 BMW motorcycle brake tail light PWM frequency duty cycle output question - Page 1
Forum section: electronics / beginners

author: poot36
author_rank: Frequent Contributor
timestamp: October 26, 2014, 07:30:28 am
content: Hi, I am needing the PWM frequency and duty cycle of a 2014 BMW motorcycles brake light / tail light for a circuit simulation. I just need the tail light mode but brake light mode would also be useful. If someone could measure this for me I would be greatfull. You can use a solar cell attached to a oscilloscope or maybe a computer sound card with the correct software installed so you do not have to take apart the bike. Mods if this is not the correct place for this topic could you please move it? Thanks.
20" LCD TV, needs 12v supply, can I run it from 18 - 20v? - Page 1
Forum section: electronics / beginners

author: Delta
author_rank: Super Contributor
timestamp: January 11, 2016, 04:36:19 pm
content: I've got a 20" LCD TV, an ONN TV model 74/62 (made for ASDA, a large UK supermarket chain).It uses a 12v 60w external PSU, which I don't have. However I do have a stash of 18-20v laptop PSUs which meet the power requirements.No although my immediate thought was, "no, don't be stupid, it'll smoke it", I then thought well it's got to have a SMPS in there, and these can work over a variable input voltage... But then I thought will there be 16v caps on the input side somewhere?Any tips?

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 11, 2016, 04:50:41 pm
content: Don't plug it in - take it apart!No, really. Take it apart and trace through the power path. The input capacitors and switcher may be readily apparent if they are part of a separate power board.

author: Delta
author_rank: Super Contributor
timestamp: January 12, 2016, 06:55:22 pm
content: So I took it apart, and found 16v electros on the input....ATX it is then....

author: Seekonk
author_rank: Super Contributor
timestamp: January 12, 2016, 07:00:08 pm
content: I often take those 18V supplies and crack them open. Voltage regulation is often just with an opto isilator resistor and zener, sometimes a LM431 adjustable zener. Pretty easy to change the voltage.

author: Delta
author_rank: Super Contributor
timestamp: January 12, 2016, 07:23:13 pm
content: Quote from: Seekonk on January 12, 2016, 07:00:08 pmGame on! I'll give that a bash tomorrow!Are they still then capable of their max power, or would I have to stick to the max current?Standby for more questions!

author: Gyro
author_rank: Super Contributor
timestamp: January 12, 2016, 07:27:18 pm
content: I suspect max current.
20x 50cm 7030SMD Led strips power supply question - Page 1
Forum section: electronics / beginners

author: supergogetassj5
author_rank: Newbie
timestamp: April 06, 2017, 08:14:25 pm
content: So I've got 10 meters (20x50cm) of 7030SMD Led strips.The seller writes:Lumen: 7030 White / Cool White about 115 lm/W; Electric power:19W-22W/1meterSo its ~350W of power. Thats not small but OK. Im looking at my local electronics store and all I see is 250w maximum of power supplies for LEDs. So I have to get two of them? Or am I calculating something wrong?Also, maybe I can use old PC PSU? But I know there is this thing called amperes? What that has to do with everything? Sorry I'm kinda very basic on electronics...Thanks

author: madires
author_rank: Super Contributor
timestamp: April 06, 2017, 08:27:03 pm
content: 20W per meter seems to be quite high. I'd take one 50cm strip and power it by a lab PSU or a 12V PSU plus a DMM for measuring the current.

author: LaurentR
author_rank: Frequent Contributor
timestamp: April 07, 2017, 01:26:09 am
content: Sounds about right. Looking at other vendors, they have 50cm strips of 36 LED, each LED quoted at 0.3W, so 72led/m x 0.3W/led = 21.6W/m350W is ok, but at 12V, that's 30 amps, which is quite a bit. You will likely have to use multiple 12V outputs of your PSU (check the ratings) and carefully pick your wire gauge to reduce IR drop (and also keep wire temp low).
220V Hot Air Station - Page 1
Forum section: electronics / beginners

author: kaytel
author_rank: Newbie
timestamp: May 12, 2019, 04:39:46 pm
content: I'm looking around for a decent budget hot air station. I've seen the Quick 957D recommended, but only found a 220V version being sold on Aliexpress. I haven't seen a 220V version listed on Quick's global site, so I am wondering if it is genuine or some knockoff. While searching I also came across an 857D on ebay, but it too doesn't appear on Quick's site. Anyone know if these are genuine Quick products?I see the Quick 861DW being widely recommended as well, but I think it will be overkill for me and it is too expensive.

author: Jwillis
author_rank: Super Contributor
timestamp: May 13, 2019, 03:23:07 am
content: I have the 861DW that I bought from a Canadian supplier on EBay.Very nice unit. Now according to specs they are rated for 110V .Canada and the USA run 120V standard but that's sort of misleading and can be confusing to many people.Many appliances and tools may be rated for varying voltages from 110V to 125V here and work just fine on 120V. Although mains can fluctuate here between 110V to 125V its still classified as 120V. Its kind of funny that after so many years a standard voltage labeling hasn't been introduced here.So in South Africa where your standard is 230V a appliance or tool that is rated for 220V should work fine.These units are manufactured in China by QUICK Intelligent Equipment Co., Ltd(CHANGZHOU) China.As for being genuine from a specific vendor like Aliexpress I couldn't say because I havn't used them.Best to try to gather as much information as you can about the vendor and make that judgement yourself.

author: wraper
author_rank: Unknown
timestamp: May 13, 2019, 03:34:07 am
content: 220V version is for Chinese market. It will work at 230V just fine. Not too long time ago appeared similarly looking knockoffs. But I have not heard about any counterfeits.

author: rawrs
author_rank: Contributor
timestamp: May 13, 2019, 06:02:47 am
content: As spectacular as off the top of my head maths is, the difference between 220 and 230v, I can safely say, is well within 10%. Hell even a line voltage of near 250v is 'within tolerance'. I've seen 265v before in one street but I'm not sure if that's within 10% or not. I have a feeling it may not be. But I feel that this may or may not be an excuse to not have to replace transformers that have had their taps maxed out by tons of solar in the street.Either way, a nominal 220 or 230v is as near as makes no difference.

author: kaytel
author_rank: Newbie
timestamp: May 15, 2019, 07:16:50 am
content: What I meant was that what I'd consider more reliable sources, like TEquipment, only sell the 110V versions of the Quick stations, while I need a 220V model. The only place I've found a 220V 957DW+ is on Aliexpress. On eBay the 220V one that commonly appears to be on sale is the 857DW+. That one doesn't even seem to be on Quick's Chinese site.
220V to 110V converter for HAKKO 808, what's really needed? - Page 1
Forum section: electronics / beginners

author: mcinque
author_rank: Unknown
timestamp: August 20, 2013, 02:06:27 pm
content: Hello,I'd like to buy an Hakko 808 desoldering pump but, since I live in Europe, I 've only 220V available as power source, while the Hakko requires 110V.For this kind of device, wich have only a ceramic resistor and a rotary pump, I guess it is not really needed an electronic step down converter, but a cheap and simple 2:1 transformer will do the trick.Do you agree with me?

author: Legit-Design
author_rank: Frequent Contributor
timestamp: August 20, 2013, 02:18:00 pm
content: Autotransformer, no need for variable one either, just autotransformer with solid tap.

author: Psi
author_rank: Super Contributor
timestamp: August 20, 2013, 02:24:13 pm
content: Do you know what type of motor the pump uses?Also, is there really only a motor and a heater? ie, no electronics at all

author: mcinque
author_rank: Unknown
timestamp: August 20, 2013, 06:50:05 pm
content: Quote from: Psi on August 20, 2013, 02:24:13 pmmmm, according tothismanual, there is a temperature control circuit with a trimmer, but I don't know what's inside.Do you think that an autotransformer cannot do the job?

author: ablacon64
author_rank: Frequent Contributor
timestamp: August 20, 2013, 07:09:40 pm
content: Quote from: Psi on August 20, 2013, 02:24:13 pm

author: mcinque
author_rank: Unknown
timestamp: August 20, 2013, 07:47:06 pm
content: it is a very simple construction, a heater and a pump; the only other part is the temperature control circuit, but as I said before, I don't know what's inside.

author: Psi
author_rank: Super Contributor
timestamp: August 21, 2013, 12:01:19 am
content: I was wondering if it would run from half wave 220V (using a diode in series)Looks like it wont.Autotransformer or stepdown is probably the best idea.
220v vs 120V SURGE SUPPRESSORS  - Page 1
Forum section: electronics / beginners

author: hriosm
author_rank: Newbie
timestamp: July 17, 2018, 08:45:34 am
content: I'm looking for decent 220V surge suppresors but they are pricey. Besides the contact form (220v half turn different from standard 120v) is there a big difference between a 220V surge suppressor and 120V? I'd like to use 120V suppressor instead of 220V if modification is easy. Would be easy to modify the 120V design to work with 220V? I´d think there is some protection in going from 120 to 220 but the main part of design would be to suppress higher than 220v peaks? Any ideas?Thanks !

author: Ice-Tea
author_rank: Super Contributor
timestamp: July 17, 2018, 09:00:00 am
content: A 120V *whatever* protection device will clamp well below 230V so, eh, no...

author: Karlo_Moharic
author_rank: Regular Contributor
timestamp: July 17, 2018, 11:18:23 am
content: Given the information that you have provided , you either don't know what surge protector is or you are refering to powerstrip with power surge protection.Could you give us a bit more information , as to what exactly are you trying to do.
23,000uF caps - Page 1
Forum section: electronics / beginners

author: BillWojo
author_rank: Regular Contributor
timestamp: July 09, 2014, 07:24:32 pm
content: Stopped at my local scrap yard today and they had a bunch of 23,000uF 75VDC caps, I think made by UCC. All sitting on top of a skid, looked new. Probably 50 to 100 of them. What would they be useful for?I didn't inquire about them but they may be available for cheap. Give me a reason to pick a few up if I can. LOLBillWojo

author: PedroDaGr8
author_rank: Super Contributor
timestamp: July 09, 2014, 08:15:09 pm
content: Quote from: BillWojo on July 09, 2014, 07:24:32 pmAudio people like them for smoothing out linear supplies and as tank caps so that when the amp "hits" it has a resevoir to draw power from.

author: rexxar
author_rank: Frequent Contributor
timestamp: July 09, 2014, 09:19:55 pm
content: Well, you could put them all in parallel and vaporize random bits of metal

author: sfiber
author_rank: Regular Contributor
timestamp: July 09, 2014, 09:27:09 pm
content: you can make a circuit with boost converter(over 50v under 60v) and make your high power discharge system.Then you can explode whatever you want.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 10, 2014, 12:07:28 am
content: See if you can bum them for $1/lb or less (it's not like they have much if any scrap value -- they are literally 50% oxidized aluminum!). Keep a few and eBay the rest in small lots.Tim

author: Po6ept
author_rank: Regular Contributor
timestamp: July 10, 2014, 01:22:41 am
content: You could build a nice battery tab spot welder...Please tell me they're in Arizona!

author: BillWojo
author_rank: Regular Contributor
timestamp: July 10, 2014, 01:25:03 am
content: Sorry, but there in NJ. If I get a chance, I'll stop by and see what kind of deal I can manage. Can't they be used to make a small rail gun? Be something neat to try.BillWojo

author: G7PSK
author_rank: Super Contributor
timestamp: July 10, 2014, 08:23:05 am
content: Build some big flash guns and sell them to photographers. Many laser systems use large capacitor banks as well, went to a hospital once and there was this heavy thumping going on upstairs making the whole floor and ceiling jump, I inquired as to what was going on and was told it was the laser in the operating theater.

author: 22swg
author_rank: Frequent Contributor
timestamp: July 10, 2014, 08:44:04 am
content: I just repaired a 300 watt studio flash the caps are 1400uF 360v . 4 of them.

author: SeanB
author_rank: Super Contributor
timestamp: July 10, 2014, 04:53:14 pm
content: I could use a few if shipping was good, as general buffer caps on batteries.
23LC1024 and 25LC1024 packages - Page 1
Forum section: electronics / beginners

author: ggchab
author_rank: Frequent Contributor
timestamp: December 11, 2016, 09:42:33 am
content: Surprisingly, the Microchip 23LC1024 is available in SOIC package while the 25LC1024 is available in SOIJ package (a bit wider). I am wondering why they use different packages for similar chips. In fact, I was planning to use the same PCB layout for both types of chips and then decide which one and how many to solder, depending on the usage. The solution is probably to make pads a bit longer, but why this difference ? Thank you.

author: mash107
author_rank: Contributor
timestamp: December 12, 2016, 04:17:57 am
content: It's probably due to the larger size of that particular die needing the extra area. The 25LC1024 is a non-volatile memory (saved contents after power off); as such, it needs special features, like a charge pump. Its cell structure is also different (i.e. larger) to ensure data retention vs the volitaile SRAM (23LC1024).I like Onsemi's serial EEPROM solutions, as they offer a smaller die that can fit in the narrow SOIC body:http://www.onsemi.com/pub_link/Collateral/CAT25M01-D.PDF

author: ggchab
author_rank: Frequent Contributor
timestamp: December 12, 2016, 07:32:52 am
content: Thanks for the suggestion. Perfect for my PCB as it has the same pin configuration
24 bit ADC converter with PGA working from 0V? - Page 1
Forum section: electronics / beginners

author: A2
author_rank: Contributor
timestamp: July 15, 2014, 04:15:34 pm
content: I had used ADS1248, it had PGA which can wirk with AVSS+0.1V. So I cannot measure sinle ended signal reference to ground.I found another IC, ADS1220, it works if we bypass PGA. But it has 4 channel unlike ADS1248 which has 8 channles?Any one IC with 8 channels & can do sinle ended measurement of small signals of range 50mV

author: adi101
author_rank: Contributor
timestamp: July 15, 2014, 08:42:55 pm
content: Look at this:http://www.microchip.com/wwwproducts/Devices.aspx?product=MCP3914It works with signals between +1V and -1V at the inputs.Very good performance at high OSR.Plus you get 8 independent synchronous ADCs.

author: tszaboo
author_rank: Super Contributor
timestamp: July 15, 2014, 08:54:07 pm
content: ADS1256Those fancy AFEs are nice for what they were designed for, but not much else. This includes all 3 devices mentioned here, the TI parts are for temperature sensors, the microchip is for energy metering. Dont use them to measure industrial signals, something obvious will not work. This can include INL, DNL errors, stupid digital interface, settling time issues etc.

author: adi101
author_rank: Contributor
timestamp: July 15, 2014, 09:15:16 pm
content: Quote from: NANDBlog on July 15, 2014, 08:54:07 pmDon't be intimidated by that, in fact energy metering requires very high accuracy.Anyway, an ADC is an ADC, you can use it in many different applications.Differential inputs are very good at rejecting noise too (just food for thought).

author: tszaboo
author_rank: Super Contributor
timestamp: July 15, 2014, 09:45:21 pm
content: Quote from: adi101 on July 15, 2014, 09:15:16 pmThe problem is, that he was asking for a srewdriver, and you gave him a hammer. A2 obviously wants to measure 0-5V signals, whicha are single ended. If he choses the AFE you proposed, the signal must be divided first to the input range, sacrificing all the accuracy.The MCP3914 doesnt have any DC accuracy. It has 0,1% offset and 9PPM reference, together with 4% gain error compared to the ±0.005% error from the device I proposed. You need to feed a clock into it, and the power supply is different.I mean, sure, you can say that you can sample it with a wolfson audio adc, and then convert the I2S signal to SPI, because that is also an ADC, right?

author: adi101
author_rank: Contributor
timestamp: July 16, 2014, 06:56:02 am
content: There is no need to argue which ADC is better.Each has advantages and disadvantages.I was just pointing a device which I know is very good.I am sure that the ADS part is also very good.Let him choose according to his application.
240 VAC dimmer switch work with 12 VAC? - Page 1
Forum section: electronics / beginners

author: kaiden.l
author_rank: Newbie
timestamp: January 14, 2020, 05:05:44 am
content: i don't work with AC much so i don't really know anything about it.i'm wondering if a 240 VAC dimmer switch can work with 12 VAC i have tried to find out my self but all i could find was 120 VAC with 12 VDC.Edit: i have been told that it will not work if anyone has an idea for something that will work please tell me ( it is for heating a nichrome wire )

author: David Hess
author_rank: Super Contributor
timestamp: January 14, 2020, 05:24:59 am
content: The trigger circuit for the TRIAC usually includes a 20 to 30 volt DIAC so it will not work on such a low AC voltage.

author: floobydust
author_rank: Super Contributor
timestamp: January 14, 2020, 05:25:57 am
content: No, not likely because the dimmer's DIAC triggers around 32V. LikeDB3You'd have to build an extra circuit to get around this, to make a bi-directional 10V DIAC for example.
240v Single Phase VFD (diagram wanted please) - Page 1
Forum section: electronics / beginners

author: SvenIronhand
author_rank: Newbie
timestamp: February 02, 2020, 07:39:05 am
content: So I have a problem. I need to build a VFD to run a pool pump motor. It's a 1.1kw/1.5HP motor (single phase). I have lots of all sorts of components at home. Also I'm in South Africa where we have 240v supply.So the question is does anyone know of a place where I can find a circuit diagram for a DIY 1.5kW/2HP VFD. I've looked but haven't really found anything. I don't have much money so I need a free or very cheap less than AU$15 diagram.

author: WattsThat
author_rank: Frequent Contributor
timestamp: February 02, 2020, 07:35:36 pm
content: It’s a fools errand attempting to DIY speed control a single phase ac induction motor.You cannot find a schematic because they don’t widely exist. Single phase induction motors don’t lend themselves to being speed controlled since there are usually one or two capacitors involved to create a phase shift required for starting and maintaining rotation along with a centrifugal switch that drops out the start capacitor when the motor reaches a preset speed.If you cannot afford a proper three phase motor that can be controlled with a commercial single phase input/3 phase output VFD, just leave things as they are since the only thing you’re likely to achieve is a pile of dead parts, a failed motor and a very unusable, dirty pool.

author: SeanB
author_rank: Super Contributor
timestamp: February 02, 2020, 07:56:56 pm
content: Easiest thing is to go find a donor 3 phase motor in the same frame size as that probably Speck pump, and do a coil transplant with the existing motor. 1.1kW is a common size, and you will find a WEG or Bonfiglioni motor that size easy enough, and so long as they are the same frame size they should fit into the frankenstein configuration. You cannot easily do a complete motor transplant, as the typical pump uses the shaft as the impellor drive, and there are not many extended shaft motors around, I had to have some small one's rewound because of that.Then there are plenty of 3 phase drivers around to power it, though you will not really get much of a control range over just bang bang switching the motor, those pumps are pretty not going to be efficient below around 40Hz anyway.I am going to get around to doing that to my drill press, though I was able to get a near perfect motor at my local scrap yard, old lift door motor in the right frame size, and with the bonus of also having the right shaft diameter and length, though if it does not fit the pulley I will be transplanting the rotor from the 2 anyway.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: February 03, 2020, 12:54:57 am
content: Quote from: SeanB on February 02, 2020, 07:56:56 pmI highly recommend VFD for a drill press. I've had one on mine for years. Its nice to have ultra low speed (including belt sheeve reduction) and reversing for things like tapping holes.
240v Single Phase VFD (diagram wanted please) - Page 1
Forum section: electronics / beginners

author: SvenIronhand
author_rank: Newbie
timestamp: January 29, 2020, 11:26:23 am
content: So I have a problem. I need to build a VFD to run a pool pump motor. It's a 1.1kw/1.5HP motor (single phase). I have lots of all sorts of components at home. Also I'm in South Africa where we have 240v supply.So the question is does anyone know of a place where I can find a circuit diagram for a DIY 1.5kW/2HP VFD. I've looked but haven't really found anything. I don't have much money so I need a free or very cheap less than AU$15 diagram.

author: GerryR
author_rank: Frequent Contributor
timestamp: January 29, 2020, 11:46:04 pm
content: Single phase motors are synchronous; VFD's are used to drive 3-phase motors. VFD's can run off of single phase power (input), but they output 3-phase to the motor. So, you need to get a VFD and a 3-Phase motor.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: January 30, 2020, 02:44:22 am
content: Many problems here. First off a standard single phase induction motor is not synchronous. It develops torque through slip just like a three phase motor. However, most single phase induction motors have switched start capacitors and possibly a run capacitor as well to start and maintain a rotating field. These need to be dealt with. I have never seen a VFD that was compatible with a single phase motor and I have literally installed about 10000 of them. In fact I have three operating in my home shop and four spares on my shelf.Single phase sourcing VFDs is common practice, but attempting to drive single phase motors with most VFDs will cause a phase imbalance fault.In addition if you are trying to control flow in a centrifugal pump with a vfd it will be difficult due to the flow characteristics of centrifugal pumps. If you are trying to save energy cost, a simple throttle valve at the outlet will work. The pump draws less power as it does less work on the fluid. Avoid throttling on the inlet because it can cause cavitation and pump inlet erosion .I don’t see a VFD as a viable option in your situation.
240v transformer - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: October 24, 2020, 01:03:56 pm
content: i have one of those adjustable desk lamps runs on some kind of strange bulb that i dont have and cant get :palm:so i am transforming it into a led version about 40 0dd leds packed in tight my question is the original power supply seems to be a transformer putting out 240v with input 240v i was wondering what was the point of it? is it just some filter? no markings on it ant also the case has no markingsps this appearse to have only 2 windings although i can not get a continuity reading or resistance reading

author: HB9EVI
author_rank: Frequent Contributor
timestamp: October 24, 2020, 02:20:28 pm
content: I doubt this is a transformer; it's most likely a big inductor acting as inductive ballast for the fluorescent bulb.what socket does the bulb have? it's still possible to get ones with LEDs implemented instead of fluorescent.p.s. could imagine that you have something like a G23 socket; look it up once in a search engine

author: madires
author_rank: Super Contributor
timestamp: October 24, 2020, 02:45:56 pm
content: Some pictures would help.

author: glinjik
author_rank: Regular Contributor
timestamp: October 24, 2020, 05:02:05 pm
content: Absolutely spot on g23 socket

author: HB9EVI
author_rank: Frequent Contributor
timestamp: October 24, 2020, 05:07:34 pm
content: I have several such lamps here, also in my workshop; I got me bulbs with LEDs fitting in the G23 socket on aliexpress; they are working fine; the inductive ballast can stay in place, it's not really needed for the LEDs but it's also not disturbing

author: glinjik
author_rank: Regular Contributor
timestamp: October 24, 2020, 05:11:31 pm
content: im not going to use it just was wondering what the point of it was but its clear now, but thank you all
240v/24v salt generator transformer - Page 1
Forum section: electronics / beginners

author: mwhitnell
author_rank: Newbie
timestamp: April 27, 2020, 02:51:44 am
content: Hi,My salt generator controller has failed...I wish to just hook up the transformer so it makes chlorine whenever the pool pump runs. I do believe it runs on 24v dc for the cell. There is a chlorine boost on the controller, so when that is active probably the 24v goes a bit higher...just a guess. So the xfmr has brn, blk, red, org for the primary, two red & one blk for secondary...I put 24v ac on the secondary two reds, and get the following between the primary: org-brn=137v, org-blk=47v, org-red=25v, blk-red=137v, brn-blk=97v, brn-red=44v. This controller is connected to 240v, but goes thru a circuit board, lcd display, etc, but the controller will not work. I measured the ohms, and brn-org is only about 1.2, blk-red is about 1.2, no continuity for any other combo. The xfmr looks about 100va, based on the size, maybe a little larger. Any idea how to connect 240v to the primary? The two secondary red wires go to four half wave rectifiers, two for each red wire, with the black a center tap. Ok, if I consider losses, it makes sense that 240 should go to the org-brn yielding 50va and ouput red-blk of around 24v. Maybe the primary has two windings, one for 50va and the second for another 50va, so 240v should go to the blk-red to provide additional current for super boost in chlorine output.

author: james_s
author_rank: Super Contributor
timestamp: April 27, 2020, 05:23:44 am
content: I don't know anything about salt generators, but it's generally not advisable to post photos on a worldwide public forum with your address overlaid on them.

author: Jwillis
author_rank: Super Contributor
timestamp: April 27, 2020, 11:42:23 pm
content: I'm not sure but there appears to be a lot of corrosion in and around the enclosure. I would visually check all the connections , traces on the PCBs and welds.

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: April 27, 2020, 11:54:09 pm
content: It really depends upon the cell. It'll need 2.5Amps up to 4Amps @24V DC dependent upon the cell size. My Zodiac I have to set the current value and also it reverses current flow every so often to reduce plate build up of carbonates.Some cells run on different voltages.....Check for corroded transistor legs! Hahaha Especially if you had Acid nearby!

author: themadhippy
author_rank: Super Contributor
timestamp: April 27, 2020, 11:58:12 pm
content: more likely the primary is 2 windings,wire them in parallel for 120 ,or series for 240,saves the manufacturers from using different transformers for different country

author: mwhitnell
author_rank: Newbie
timestamp: April 28, 2020, 12:31:08 pm
content: If I wire in series or parallel, I would have to know how the windings are wound, if I wired one way, I might get no voltage ouput, and the opposite wound would provide 24v output, right?