hybridfree/eevblog-posts huggingface dataset:
Weird rotary encoder behavior - Page 1
Forum section: electronics / beginners

author: magborresen
author_rank: Newbie
timestamp: July 24, 2021, 08:02:42 pm
content: First post, so forgive me if I'm am in the wrong category.I am doing a project which involves a rotary encoder. A piece of hardware that I haven't worked much with before but I get how it works.So I am doing some hardware debouncing using a RC filter, schematic is attached. I have changed the filter resistor to 220 ohm and the cap to 0.22 uF as that was the smallest cap I had on hand.Both pins have been pulled up to 5V by 10k. When I probe over the filter and turn the encoder in either direction, I see pin B going to 0 but pin A barely reaches 4V. I have no idea why this is happening and I cannot for the life of me get it to work. When I probe directly on the encoder output it works perfectly fine, although with the bounces.Any ideas as to what is happening?Any ideas?

author: Manul
author_rank: Super Contributor
timestamp: July 24, 2021, 09:09:59 pm
content: I also notice that your channel 2 shows very sharp rising edge, not like channel 1. If pullup is 10k and capacitor 0.22uF I don't think that such edge is possible. Logic level of 4V volts means that voltage divider is somehow formed. There is no other way how such in between voltage can be produced. So something is wired wrong. It happens to all of us. Sometimes we are just blind and can not see obvious things. The fast rising edge means that either pullup is very small, there is no capacitor or capacitor is very small. 4V low level means that some resistor is in series with encoder contacts.Have you tried to measure contact resistance of encoder? Have you tried to switch A with B, but leave everything else same?

author: magborresen
author_rank: Newbie
timestamp: July 25, 2021, 06:43:06 am
content: That was my conclusion as well. I just cannot figure out why that voltage divider forms, since I can measure the pull up on the "faulty" pin to be correct. I'll try to switch stuff around again.

author: magborresen
author_rank: Newbie
timestamp: July 31, 2021, 06:40:20 am
content: So the pin I was connected to on the uC was shorted to VCC with 23 ohms of resistance. This was what created the voltage divider. Check your pins. Works perfectly after switching the pin around
Weird simple car battery charger - Page 1
Forum section: electronics / beginners

author: Eldi4
author_rank: Contributor
timestamp: January 12, 2019, 12:30:20 pm
content: Hello,Excuse me, it is probably a very very beginner questionI've been looking for a simple car battery/lead acid battery charger using 12V Linear Transformer to charge 1Ah to 100Ah (or literally any capacity) car battery/ lead acid battery, and then i found this oneI think there are something wrong with this circuit, my analyze is the relay will be cut-off when the voltage is around 11V, and when the voltage is above 11V the relay is on, and will never going off again except the voltage is going down to 11V, so i think it is more likely a Overdischarge protection circuit rather than a charging circuit,But if i flipped the the op-amp non-inverting and inverting input, and change the +12V (which is a supply voltage) on the inverting input (after flipped the input) side of op-amp to battery voltage instead, the relay will be off when the voltage exceed 14.2V and turn on again when the voltage is going down to 12.2V.Are my analyze is right?, this charger will be working when i flipped the op-amp input.If you have any ideas please tell me, or you have a suggestion on a simple car battery charger.

author: ArthurDent
author_rank: Super Contributor
timestamp: January 12, 2019, 02:01:23 pm
content: Check the data sheet for the LM311 which isn't an opamp but is a comparator.

author: Ian.M
author_rank: Super Contributor
timestamp: January 12, 2019, 03:11:42 pm
content: ALM311is a differential comparator not an OPAMP.There's something screwy about the circuit round it. Normally you'd have positive feedback to provide hysteresis, but it looks like that arrangement has negative feedback via R1 (270K) and that's going to make its switching transitions mushy and may even make it oscillate due to C2.With in+ > in- the LM311 collector output will be high (see datasheet p13 section 9.2.2.1 Input Voltage Range) and the relay will be on. It looks like an undervoltage lockout circuit so it only connects the 12Vin to the battery output if the 12Vin is high enough to charge the battery. Consider a caravan 'house' battery being charged from the tow vehicle. When the engine is stopped the relay would disconnect the 'house' battery from the vehicle battery so loads on the 'house' battery (e.g. fridge) don't drain the vehicle battery overnight leaving you stranded in the morning.It gets away without an over-voltage cutout for the end of charging by having a transformer that at nominal mains voltage only just puts out enough voltage to reach fully charged. However odds are its float voltage is too high for long battery life unless its not maintenance free and you keep it well topped up. When you use its 12Vin, it relies on the vehicle'a alternator regulator to limit the charging voltage.Unless you need the capability to charge from a 12V vehicle supply, this charger has very little to recommend it, and it is likely to drastically shorten the life of SLA and maintenance free batteries.
Weird solenoid unexplainable oscillation - Page 1
Forum section: electronics / beginners

author: little_carlos
author_rank: Regular Contributor
timestamp: July 19, 2015, 06:52:06 pm
content: Hello guys, im having some troubles with a solenoid that im trying to controlim trying to make a solenoid oscillate using a 555 timer, the timer output goes to tip31c and it controls a relay, when i dont connect the solenoid, everything works as how i want, at 1hz, the relay activates at the speed it should be, but when i connect the solenoid, it starts to oscillate at a high frecuency as well as the relay, both start to oscillate at a high speed, anyone knows what is happening?both relay and solenoid has their own flyback diode, the power supply is 12v 2amps capable, the solenoid is 12v 200mA, it does work ok, ive tested it without the 555 timer, im trying to use it as a piston to move a little box.any known of what is happening?

author: AF6LJ
author_rank: Unknown
timestamp: July 19, 2015, 06:59:31 pm
content: With what you have provided to work with, my first stab at this problem would be that the 555 is being spiked by the current draw from the solenoid.Try running the 555 from a separate supply, or a lower regulated voltage from the same supply source.As a side note;Grounding becomes a big deal in these kinds of circuits.If the ground / common lead is shared between the 555 and the relay / solenoid noise on the ground line can cause this kind of stuff to happen.

author: little_carlos
author_rank: Regular Contributor
timestamp: July 19, 2015, 07:09:42 pm
content: i did what you said, i used 2 different power supply's and now it works properly

author: AF6LJ
author_rank: Unknown
timestamp: July 19, 2015, 07:20:27 pm
content: Now what you might try is bringing your ground leads back to one point in the circuit where the - lead of your supply will be connected.Do the same with the + connections.If it starts acting up, you need to decouple the 555 in some manner.You can do this by running your circuit off a higher voltage; say 15V or 18V and run the 555 off a 12V regulator.Depending on your circuit you could keep the +12V and down-regulate the 555 V+ to 8V. The regulator will provide the decoupling.The 555 timer is picky when it comes to having a clean supply to run from.
solved: Weird terminal block plug? - Page 1
Forum section: electronics / beginners

author: incf
author_rank: Frequent Contributor
timestamp: April 25, 2025, 11:50:45 am
content: What is the attached terminal block plug for? Mechanical interlocking?edit: "pull out aid" apparently

author: gcewing
author_rank: Regular Contributor
timestamp: April 27, 2025, 11:45:58 am
content: Maybe also for strain relief, with a cable tie through the two square holes?
Weird - Page 1
Forum section: electronics / beginners

author: Abayomi
author_rank: Contributor
timestamp: August 12, 2016, 11:20:54 pm
content: Any help please. I was building a power supply circuit that required 30v 1A transformer but i did not stumbled on the transformer so i bought 2A 15-0-15 transformer ,strangely at the rectifier stage I measured the output at the smoothing capacitor it is 52.1v. Funny enough I connected a resistor in series with a zener diode of 30v across the 1000uF still got the same result

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 13, 2016, 03:12:19 am
content: This all seems correct- the capacitor will charge to the peak voltage from bridge (~ 1.414 x 30V)You added the zener and resistor and measured the voltage across the capacitor as being the same as before.The 30 volts can be measured across the zener. The current available from the voltage regulated circuit will be limited by the resistor value and the voltage difference- as the drawn current increases, the current through the zener will decrease until no current flows through the zener and the voltage will no longer be regulated and will start to fall.You have two output voltages to use- one of 50V DC high current and the other of 30v DC low current.Regards,BT

author: Audioguru
author_rank: Super Contributor
timestamp: August 13, 2016, 01:01:50 pm
content: The "30V" transformer must produce 38V RMS for the rectified and filtered DC to be 52V.If the transformer is a cheap tiny Chinese one rated for only 100mA then it will probably produce 38VAC or more with no load. The 30V transformer rated at 2A will probably produce 31.5V with no load.Maybe your mains voltage is much too high?

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 14, 2016, 12:48:24 am
content: Thanks Audioguru- I forgot to point that out to Abayomi.The transformer rated voltage will be when the transformer is supplying the rated current. If no current is being delivered then the voltage will be higher- how much higher depends on the transformer physical construction which is beyond the scope of this thread (text book required !)BT

author: rch
author_rank: Regular Contributor
timestamp: August 14, 2016, 11:15:01 am
content: In the old days we used to get the output down to near the RMS voltage (but still highly load dependent) using inductors and capacitors to filter the 100/120Hz. Nowadays I suppose you use an active device as a filter/regulator.

author: wraper
author_rank: Unknown
timestamp: August 14, 2016, 12:03:56 pm
content: Quote from: BurningTantalum on August 14, 2016, 12:48:24 amAnd the lower is transformer power, the higher will be the difference between voltage rating under load and not loaded voltage.
Weirdness on Oscilloscope? - Page 1
Forum section: electronics / beginners

author: sci4me
author_rank: Regular Contributor
timestamp: June 13, 2015, 10:08:55 am
content: Hey guys! So, this is my first time really working with an oscilloscope so go easy on me.I have it hooked up to an arduino doing PWM. As I increase the duty cycle, everything is fine, until it gets too high. Then the signal shown on the display gets all weird.Video:https://youtu.be/eRLF5hF5V6gI was wondering if you could tell me the cause of this. Thanks!

author: con-f-use
author_rank: Unknown
timestamp: June 13, 2015, 10:11:13 am
content: Trigger is drifting?

author: sci4me
author_rank: Regular Contributor
timestamp: June 13, 2015, 10:16:00 am
content: Mmh, I was able to get it to act normally by messing with the trigger a bit. Thanks. Now I need to go research this so I can understand it...

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2015, 11:46:46 am
content: Why did you take down the video?
Welder transformer replacement - Page 1
Forum section: electronics / beginners

author: AdamB
author_rank: Newbie
timestamp: June 14, 2018, 05:03:47 am
content: Hi allI am interested in replacing the transformer in my entry level 90amp MIG welder.https://ozito.com.au/products/90amp-gasless-mig-welder/This is the basic model sold all over the world. The most common modification for this type of welder is to rectify the output and add shielding gas capabilities so solid core wire can be used. I am planning on making these modifications but first, I would like to add a larger transformer from an old TIG welder I don't use. I know that TIG welders are constant current and Mig welders are constant voltage I am just wondering if the transformers are different or if there is a circuit on the output that keeps the voltage output constant like capacitors.Photo of welding circuit:http://sbrowne.me/welder-wiring-diagram/chicago-electric-90-amp-flux-wire-welder-68887-page25-wiring-diagram/Sorry if this is confusing I'm new to this forum

author: richard.cs
author_rank: Super Contributor
timestamp: June 14, 2018, 12:13:23 pm
content: Usually constant current in a welding transformer is achieved with magnetic shunts in the transformer. These are usually adjustable mechanically (they slide in and out) to change the current and it may be possible to completely remove them. If the adjustable shunts can be removed, and if there are no fixed shunts (sometimes these can be knocked out with a punch but it it quite easy to damage the windings when doing so) then the transformer will behave as constant-voltage,butonly at one fixed voltage. Unless the transformer has multiple taps and a fixed but removable shunt (at opposed to no taps and an adjustable shunt) you will only get one constant-voltage power level.Do you have photos of the transformer you want to use?

author: tpowell1830
author_rank: Frequent Contributor
timestamp: June 14, 2018, 10:38:27 pm
content: I have no experience with this, however 'TPAI' rebuilds these pretty often, maybe you can find one of his videos that will help.https://www.youtube.com/channel/UCDbWmfrwmzn1ZsGgrYRUxoA/videosHope this helps...

author: Stray Electron
author_rank: Super Contributor
timestamp: June 15, 2018, 01:53:59 am
content: You need to go look at the Welding Web forum. They have a long running discussion about ways to upgrade the HF welders. And plenty of comments about why it's not worth the effort!

author: AdamB
author_rank: Newbie
timestamp: June 15, 2018, 03:50:51 am
content: Thanks all for the replies.turns out the 90 amp transformer in the machine has no shunts.I should be able to remove the shunts without damaging the windings as I've had experience with MOTs.I'm going to either use the output amp adjustment circuit in the old TIG welder or I'm going to build one with the circuit from Dansworkshop. One more question; if I remove the shunts should I push the secondary winding down so it is sitting on the primary like in the picture below:or should I leave them where they are? (BTW the photo is the transformer in my machine)
Welder won't weld - Page 1
Forum section: electronics / beginners

author: Kuria
author_rank: Newbie
timestamp: November 27, 2017, 06:06:21 pm
content: hello I'm new here and very much a bigginer to postingMy welder a 200p ac\dc pulse won't weld.It switches on but the OC light is always on and the whole thing is blocked.I have tested the mosfets good, thermalfuse good, disconnected inverter board output, tested all mosfets on low pressure circuit board, disconnected everything connected to low pressure cb and the warning light just won't switch off. It seems I don't have any pulse sending to the inverter board which btw receives 380 , I tested all diods good, Schottky diods good, silicon diods good, even replaced a 16 pin chip and cleaned the boards with board cleaner i trouble shooted with the repair service I bought it from nothing.Has anyone else had this problem? I'm posting photo s of the machine and boards.What the hell controls that protection mechanism?Thank you
Welding to thin pt plated nickel wires - Page 1
Forum section: electronics / beginners

author: anvoice
author_rank: Frequent Contributor
timestamp: November 25, 2024, 11:07:04 pm
content: Following the tradition of act now, think later, I got some PT1000 thin film temperature sensors with platinum plated nickel leads. Only to realize later soldering requires an aggressive flux, which I don't have. So I was hoping to weld it, but alas, no welder. If I understand correctly, I can use a capacitor or several in parallel (I have a total of five 4700uF 50V electrolytic caps) to weld, and I read about someone here using a 4700uF cap charged to 16V to weld such wires. Questions: what's the safest way of doing this without obliterating the thin leads? Is there a good starting point for capacitance/voltage?
Weller soldering gun Hi/Low switch - Page 1
Forum section: electronics / beginners

author: robsims
author_rank: Frequent Contributor
timestamp: October 16, 2022, 08:21:04 pm
content: Hi, i have a question about Weller soldering guns. Can someone please tell me why Weller puts the higher temp setting on the first click of the switch and the lower temp on the second click of the switch? If it makes no sense i want to rewire the switch and make the lower temp setting come first. Many thanks

author: TheNewLab
author_rank: Frequent Contributor
timestamp: October 17, 2022, 01:24:02 am
content: Wound like a great plan to me! Not the first time I've experienced the same. a setup that seems strange or backwards. I guess some designers just think differently.

author: MikeK
author_rank: Super Contributor
timestamp: October 17, 2022, 01:30:06 am
content: FWIW, I think this guy rewires the switch of his Weller in this:

author: robsims
author_rank: Frequent Contributor
timestamp: October 17, 2022, 03:20:25 pm
content: I contacted Weller, but still no answer

author: robsims
author_rank: Frequent Contributor
timestamp: October 17, 2022, 03:22:41 pm
content: Quote from: TheNewLab on October 17, 2022, 01:24:02 ammaybe some dumb marketing manager ordered to do this

author: robsims
author_rank: Frequent Contributor
timestamp: October 17, 2022, 03:26:59 pm
content: Quote from: MikeK on October 17, 2022, 01:30:06 amHe rewired it before making the video
Weller WES51 Part?? - Page 1
Forum section: electronics / beginners

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: January 31, 2014, 05:01:33 pm
content: what is the gold piece in the middle of the pic

author: electronics man
author_rank: Frequent Contributor
timestamp: January 31, 2014, 06:39:47 pm
content: does this dmm have fuses if not then i think its a polyswitch

author: david77
author_rank: Frequent Contributor
timestamp: January 31, 2014, 06:42:11 pm
content: Not a DMM, it's a soldering station ;-)I'd be far more interested what that reed contact on the lower left side is good for?

author: george graves
author_rank: Super Contributor
timestamp: January 31, 2014, 07:35:00 pm
content: Quote from: david77 on January 31, 2014, 06:42:11 pmIt's the lock-out switch for temp control using a magnet to trigger it.
Weller WES51 - Page 1
Forum section: electronics / beginners

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: January 14, 2014, 02:16:30 pm
content: But I wanted to know if there is a way to test the unit without a IronAre there any problems with these unitsWhat tip do you guys use and the reason I am asking I am use to hakko tips..P.S.My hakko took a swan dive and broke the whole case and now the only thing left it the circuit boards which still works but looks funky trying to use .... RIP Hakko 939ThanksJason SR__________________Nathan:Didn't I tell you not to go out, didn't I?Shilo:You did, you did...Nathan:Didn't I say the world was cruel, didn't I?Shilo:You did, you did...Nathan:Then tell me how this happenedWhat I did wrong, tell me whyCan't we just go home, Shi,And forget this dreadful night?

author: Sigmoid
author_rank: Frequent Contributor
timestamp: January 14, 2014, 06:59:06 pm
content: Well you could 3d print a new case for the hakko.I'd hate throwing one out just for the case.Anyway, the Weller is a good solid device, I grew up on its predecessors, and currently own one.I have no idea how I'd test it without an iron. Maybe by getting an iron for it.

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 14, 2014, 07:02:55 pm
content: For that reason I prefer a soldering station made of sheet metal.https://www.eevblog.com/forum/reviews/picked-up-a-damaged-jbc-bd-1ba-station-advice/?action=dlattach;attach=64036;image

author: lapm
author_rank: Frequent Contributor
timestamp: January 14, 2014, 07:03:54 pm
content: You could try glue it together? There is special glues just for gluing plastics that seems to work well on my experience. Of course it docent look perfect, but should hold just fine.

author: SeanB
author_rank: Super Contributor
timestamp: January 14, 2014, 08:20:01 pm
content: Broken case is easy to fix using quickset epoxy. Fills gaps, even can fill in for missing pieces.

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: January 15, 2014, 02:28:02 am
content: Sorry I don't have a 3D printer...The case has been repaired many times before and still falling apart .. So after this time I decided to either buy a used replacement or just buy a new or used station and work on it later when I have the time or sell it but not sure yet..

author: Odysseus
author_rank: Regular Contributor
timestamp: January 15, 2014, 02:47:22 am
content: I have this model, and love it to death. The includedETAtip does the trick for almost everything, but i picked up anETHfor fine work.My only complaint is the included sponge. It tends to accumulate solder in the pores of the sponge, making it hard to clean. I like thesespongesa lot better. Ten sponges for two bucks!

author: amyk
author_rank: Super Contributor
timestamp: January 15, 2014, 07:22:45 am
content: Get a Hakko clone, transplant the internals. (Or maybe you can buy the clone case itself from Alibaba/Taobao)
Weller wfe - Page 1
Forum section: electronics / beginners

author: Charlie86
author_rank: Regular Contributor
timestamp: December 04, 2017, 09:40:52 am
content: Hi,Is it possible to connect small weller wfe-p fume extractor to big fume extractor tube from wfe 2es? I know tube in wfe-p is a lot smaller but I can use adaper, my question is does wfe-p have enough power for wfe 2es tube.

author: macboy
author_rank: Super Contributor
timestamp: December 04, 2017, 02:52:09 pm
content: No, they are completely different products with different method of use.

author: Charlie86
author_rank: Regular Contributor
timestamp: December 05, 2017, 07:06:16 pm
content: OK, thank you for info.

author: Raj
author_rank: Frequent Contributor
timestamp: December 12, 2017, 04:40:33 pm
content: Now there's something a duck tape can fix.
Weller wx1011n with wxmpms micro iron? Any good? - Page 1
Forum section: electronics / beginners

author: wadmancpu
author_rank: Contributor
timestamp: September 13, 2019, 04:12:25 am
content: Hey, I'm looking at a weller wx1011n soldering station with the wxmpms micro iron and I was wondering if anyone has any experience with it? I have an opportunity to buy a brand new one for $350, substantially lower than normal and it looks like the micro iron would be ideal for my work. Any thoughts would be appreciated, thanks.

author: agehall
author_rank: Frequent Contributor
timestamp: September 13, 2019, 05:13:06 am
content: I have a WX2 station with the same micro pencil and I love it. For work on small components it is just great. If you aim to desolder larger TTH components, you need a beefier iron but for SMD the micro pencil is great.
WEP 858D  - Page 1
Forum section: electronics / beginners

author: gianniskar
author_rank: Newbie
timestamp: June 25, 2018, 10:46:32 am
content: Hi.Is this good hot air station about 40 euro?I know it is copy of ATTEN,but i want for non proffesional use.

author: kripton2035
author_rank: Super Contributor
timestamp: June 25, 2018, 10:57:03 am
content: just verify the ground is wired properly, and line and neutral are not reversed like other atten clones.

author: gianniskar
author_rank: Newbie
timestamp: June 25, 2018, 11:05:44 am
content: thanks for reply.This product is the "best" clone 858d or other brands like YIHUA etc?

author: kripton2035
author_rank: Super Contributor
timestamp: June 25, 2018, 03:11:13 pm
content: I had a yuhua one, that worked more than a year, and enned up almost making my house burn if I hadnt been just beside to shutdown the power ...so yihua is not a "best" brand for me.they are all the same. if you want a good one, buy a quick dw861. otherwise be prepared !I bought a Quick since...
Were can I find this motor - Page 1
Forum section: electronics / beginners

author: frog2
author_rank: Newbie
timestamp: September 29, 2023, 05:18:12 am
content: Hey all, I've been looking at these forums over the years for advice. The extent of my skills is to take things apart and replace burnt components.I have a question this time. Is there a place to buy a hard to find motor? I'm looking but no one seems to have it. It's part of a snap-on drill that's worth fixing for me.part numbersJohnson HC383XLG-011Snap-on CTS561-566RJohnson HC383XLG-020 (might work?)"1030231 Johnson" (printed on the motor but doesn't bring up anything)I've tried all the usual places ebay, amazon, aliexpress. Is there anywhere else I can check for this? Thanks in advance.

author: Haenk
author_rank: Super Contributor
timestamp: September 29, 2023, 05:33:32 am
content: I assume it is a custom part, you need a donor unit - or maybe it can be purchased as spare part (likely expensive).

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: September 29, 2023, 05:36:19 am
content: https://shop.snapon.com/repair-product/Assembly%2C-Motor---Pinion/CTS561-566RAvailable for backorder, so that's better than discontinued.

author: frog2
author_rank: Newbie
timestamp: September 29, 2023, 06:24:05 am
content: thanks, I don't know why I didn't just look there...pricey for a little motor, I guess if I really want it I'll need to pay the reseller tax

author: u666sa
author_rank: Frequent Contributor
timestamp: September 29, 2023, 07:32:16 am
content: Quote from: frog2 on September 29, 2023, 06:24:05 amhttps://aliexpress.ru/item/32834217654.html?sku_id=10000000166210452&spm=a2g2w.productlist.search_results.1.28074aa65Zpczghttps://aliexpress.ru/wholesale?SearchText=7%2C2+v+%D0%BC%D0%BE%D1%82%D0%BE%D1%80+%D0%B4%D0%BB%D1%8F+%D0%BE%D1%82%D0%B2%D1%91%D1%80%D1%82%D0%BA%D0%B8&g=y&page=1&searchInfo=iBZwUHd+Uy3LqXUNXx%2FEulYwuhE6Yibf5UdqvhetuBWZ0zUBXCT4R0rCSKNi1r+dj5%2F%2FIsuOdrtL3+rgG6FlNpdksUgSTiHDtL98pte1TBZdBKSdEY6R0ZySTHKlEuXu8B2VvxSOvhtksH+AXECDzOnRapfrsPdRhvwwZe5eiImoTtwwhttps://www.alibaba.com/product-detail/7-2v-electric-Compact-Size-Low_60749107375.htmlhttps://www.365ersatzteile.de/fleckenreiniger-pumpe-kpl-einschl-motor-hc383xlg-18v-dc-/product.pl?pid=3263413

author: amyk
author_rank: Super Contributor
timestamp: September 30, 2023, 12:30:51 am
content: https://datasheetspdf.com/pdf-file/1303807/JohnsonMotor/HC383XLG-011/1It's a "390 size" motor. Look for one with approximately the same voltage, speed, and powe output, and it should work.

author: liaifat85
author_rank: Regular Contributor
timestamp: October 01, 2023, 04:53:47 pm
content: You can contact this websitehttps://www.tradekorea.com/product/detail/P348305/Johnson-Standard-Low-Voltage-DC-Motor.html
fluke style on a scope posible? - Page 1
Forum section: electronics / beginners

author: Mark_C
author_rank: Newbie
timestamp: December 09, 2016, 06:41:55 pm
content: Hi All,My first post here.I'm an Electrical Engineer try to become an Electronics Engineer by self study.Learnd A LOT here and today I actualy solved a cable (150 meters) error at work with my DIY TDRfrom w2aew on my realy nice home made PCB....but now a need a help/hint.my Fluke FC3000A Current clamp, that realy sucks, gives me a really nice pichttp://i876.photobucket.com/albums/ab322/markcremer/Graph_01_zpsm7ljeddo.pngand my to 1104 upgraded Rigol that I really like give only AC Waves with my current clamps. (Chinees Hantec) and that sucks.and the waves that sucks....is it a settingor do i need a circuit to get the Rigol wavesgraph te becomes like de the fluke graph... (stacked values)thanks in advanced.Mark

author: daveshah
author_rank: Unknown
timestamp: December 10, 2016, 09:28:58 am
content: If you only need to see peak values rather than RMS you could probably put the scope in "peak detect" mode or similar and use a slow timebase, and just look at the top or bottom "boundary"

author: Mark_C
author_rank: Newbie
timestamp: December 10, 2016, 06:59:03 pm
content: Well I tried a bridge rectifier to make the signal dc that worked only now ...the rectifier needs a bout 600 mV to open so my reading start also at 601 mV (its about 6 Amps AC)so I mis the first 6 Amps....Is there a way to boost the ac voltage 10 times...so Ill have 6000mV.than I will step down 10 times in the dc circuit.for measuring Mains its not need to exact. 0,5 amps is fine in a range 0 to 100 amps.Thanks
westinghouse video from the 1940's - Page 1
Forum section: electronics / beginners

author: ptricks
author_rank: Frequent Contributor
timestamp: November 18, 2012, 01:04:59 pm
content: I came across this video on youtube and thought it might interest some others. It is about vacuum tubes and was made I think in the 1940's. It explains a lot about a tech that isn't used much anymore.

author: saturation
author_rank: Super Contributor
timestamp: November 18, 2012, 04:04:27 pm
content: Yes, its fairly complete overview, thanks a ton for the links.

author: free_electron
author_rank: Super Contributor
timestamp: November 18, 2012, 04:08:05 pm
content: So the message is : vacuum tubes were built to win the war.I always knew they were evil.At least ic's were built during the flower power era.

author: saturation
author_rank: Super Contributor
timestamp: November 18, 2012, 04:17:33 pm
content: Yes, I would hazard to say that military applications drive electronics faster than peacetime. One only other driver, but not as acute, in healthcare.http://en.wikipedia.org/wiki/Silicon_Valley#Social_roots_of_information_technology_revolutionIC grew around the Vietnam war with Chinese and Russian electronic warfare help to the North Vietnamese, and the space program. Today the USA military spending keeps USA too in the forefront of electronics.In the 1930-40s, it was military needs that actually gave birth to silicon valley, and many companies grew from military contracts, in particular Bill and Dave's HP. That's partly why so much of the gear was built like tanks, to serve military contracts.Quote from: free_electron on November 18, 2012, 04:08:05 pm

author: Unknown
author_rank: Unknown
timestamp: November 18, 2012, 07:50:08 pm
content: Quote from: free_electron on November 18, 2012, 04:08:05 pmYes, and those ICBMs and the space program (two major driving forces behind development of IC technology) served to deliver flowers across the globe. World-wide delivery in 30 minutes or less or your next bouquet is free.

author: Simon
author_rank: Unknown
timestamp: November 19, 2012, 09:04:38 pm
content: I like the bit at the end about english radar, a silent admission that they yanks should have taken it seriously ?
WFP3205 as replacement to irfz44,any other one SMD? - Page 1
Forum section: electronics / beginners

author: dave_j_fan
author_rank: Regular Contributor
timestamp: April 09, 2018, 02:41:05 pm
content: Hi ,I am using a inverter like circuit with IRF z44 , the 2 MOSFETS feed to center TAP transformercan u swap with WFP3205freQ 30-40khz , max current 2Amp

author: Zero999
author_rank: Super Contributor
timestamp: April 09, 2018, 03:43:39 pm
content: No one knows because you've not provided the schematic.They are not equivalent. The WFP3205 may have a lower on resistance, than the IRFZ44, but it has a lower voltage rating, 50V, rather than 60V, a lower maximum junction temperature, 150oC, rather than 175oC and a higher gate capacitance and overall gate charge, meaning it has higher drive requirements, to get the same speed as the IRFZ44.https://www.vishay.com/docs/91291/91291.pdfhttp://www.winsemi.com/upload/20140926005710_7815.pdf

author: dave_j_fan
author_rank: Regular Contributor
timestamp: April 10, 2018, 03:49:12 am
content: scheme is too messdup but its a 12v system powering a LED downlight .. i appreciate for the pointerscan i have a cheaper FET max current is 5AMPS

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 10, 2018, 08:00:59 am
content: Quote from: dave_j_fan on April 09, 2018, 02:41:05 pmyes you should can. WFP3205 is double the capacity of IRFZ44, better Rdson. both WFP3205 and IRFZ44 will be way overkill for your 2A need, ymmv.

author: Zero999
author_rank: Super Contributor
timestamp: April 10, 2018, 08:56:07 am
content: Quote from: Mechatrommer on April 10, 2018, 08:00:59 amIn this case yes, no doubt, assuming the MOSFET is only switching 12V and it's not in a high temperature environment.
What?! Why did my LED burn out? - Page 1
Forum section: electronics / beginners

author: CheekyRobot
author_rank: Contributor
timestamp: November 22, 2020, 11:38:28 pm
content: Okay, this is doing my head in. I thought I KNEW how to calculate the resistor value for a simple LED.Excuse the crude text-schematic here, but nothing special going on...+12v o--->|-----o gndAll I wanted to do was run an LED off a 12v supply rail. Powered by a 4s LIPO through a 12v linear regulator.LED is UK Farnell SKU 2900671 UV led with Vf of 3.3v(typ) Ir(typ) of 30mA.The usual led resistor calculators say 435r at 20mA.Slapped in a 470r because I've got loads soldered to quickly made red-neck PCB. Checked it, buzzed it all out with a meter, no shorts (esp across the res). All simple SMD parts, nothing I've not done hundreds of times before.Connected it up, plugged in and the LED flares up and dims down like it's burned out.After some head-scratching, I just hooked it up to the 5V supply out of frustration and (there's two of these on the board) the LEDs light up at uneven brightness... just liike they're damaged.12v supply is okay because it's running other more delicate electronics just fine (and some other LEDs!).SO.... what did I miss???

author: Paul Rose
author_rank: Regular Contributor
timestamp: November 22, 2020, 11:43:00 pm
content: Your calculation checks out. 470R should give you about 18.5 mA from 12v - 3.3v.Any chance you bridged your 470R SMD while soldering?

author: CheekyRobot
author_rank: Contributor
timestamp: November 22, 2020, 11:48:22 pm
content: Quote from: Paul Rose on November 22, 2020, 11:43:00 pmThanks for the second pair of eyes on that. Did a continuity check across both resistors and all tracks. No shorts - so unless it shorted magically AFTERwards... but I also cleaned it all up nicely to avoid solder balls, flakes of copper etc. Even inspected under the lab microscope. Clean as a whistle. Unless... this is some odd burn-in property of UV leds that I dont know about!

author: sleemanj
author_rank: Super Contributor
timestamp: November 23, 2020, 12:11:45 am
content: > All simple SMD parts,SMD resistor marking "470" means "47 Ohms" not "470 Ohms", would be the most likely mistake to make, 200mA instead of 20mA would indeed let out magic smoke.

author: CheekyRobot
author_rank: Contributor
timestamp: November 23, 2020, 12:24:29 am
content: Quote from: sleemanj on November 23, 2020, 12:11:45 amThat's a good idea. Happly, I've got all my parts nicely labelled and in fancy little draws. So 100% sure they're 470r... I even checked a sample as wellBut it's solved now. Occam's razor being the sharpest tool in the box and Paul was right! Even though I'd checked it all out nicely and examined under a mic, after I'd carefully enclosed the wire-end in shrink-wrap, a TINY LITTLE bit of wire had gotten loose and had indeed secretly shorted out the resistor under the wrap! BAH!!!! S@D'S LAW!!!Ah well, the other LED was working so I'll just get some more. Thanks all for suggestions- glad it was something STUPID in the end.
What about these as PSU load testers ? - Page 1
Forum section: electronics / beginners

author: MathWizard
author_rank: Super Contributor
timestamp: June 01, 2022, 12:48:48 am
content: I was watching a video about making a basic hotplate setup for PCB heating, and he uses some cheap, 12V 200W heater elements off Amazon. And they have lots of models. Later this year I'll have lots of time to make stuff like that.https://www.amazon.ca/s?k=Electric-Ceramic-Thermostatic-Heating-Element&crid=MVLTSGD47IJY&sprefix=electric-ceramic-thermostatic-heating-element%2Caps%2C86&ref=nb_sb_nossThe only high power PSU's I have that could run them, are 750W computer power supplies...And for ages Ive been wanting a compact, cheap way to load test some of them.So aside from not being a regulated load, and any temperature profile they might have. What else would be as cheap as these, as a 12V load tester, that's actually not going to burn out from heat?My memory says cheap power resistors, and 12V lamps would be a lot more than 20-30 dollars.And what sort of issues would there be, maybe inductance, if you wanted to feed the heater current, from a bank of mosfets, that u could PWM ? Then that's like making a regulated heater circuit anyways.So I should get a couple of these. Anyone else try them just as dirty load testers ?

author: bostonman
author_rank: Super Contributor
timestamp: June 01, 2022, 03:31:37 am
content: It seems like you want to test each voltage such as the 12v?I got one off eBay or Amazon a few years ago. It's one from China I think (see attached instructions) and works quite well. Unfortunately I don't know the model number, but here is a link to either the same one a similar model.https://www.amazon.com/MakerHawk-Electronic-Adjustable-Intelligent-Resistance/dp/B07F3NHHST/ref=asc_df_B07F3NHHST/?tag=hyprod-20&linkCode=df0&hvadid=242041198988&hvpos=&hvnetw=g&hvrand=13071928957886760127&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001893&hvtargid=pla-489007123131&psc=1

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 15, 2022, 12:38:57 am
content: Quote from: MathWizard on June 01, 2022, 12:48:48 amA bundle of "enameled" wire dunked into a bucket of water.Or even galvanized steel wire in a bucket of water, but you have to prevent shorts between different sections, for example by winding it around some spacer.Water does conduct a bit of electricity, but not much, and it depends a lot on how dirty it is.
What all do I need to know in order to help design a wiring harness and bus-bar? - Page 1
Forum section: electronics / beginners

author: ReallyBigCabbageBoi
author_rank: Newbie
timestamp: December 06, 2024, 09:52:11 am
content: Hi, as part of an internship I'd be working on wiring harness design and bus-bar for an electric bike. This is my first time working on this and they have asked me to do "my research" and at the moment I am feeling pretty lost, what's a good place for me to start?Thanks

author: armandine2
author_rank: Frequent Contributor
timestamp: December 06, 2024, 10:37:06 am
content: ZPD - starting from whatyouknowhttps://www.simplypsychology.org/zone-of-proximal-development.htmland a few youtube videos..it appears to me to be something of a "malleable part"
What am I doing wrong in ltspice? - Page 1
Forum section: electronics / beginners

author: avogadro
author_rank: Contributor
timestamp: February 13, 2020, 11:36:38 am
content: Hello,Im trying to do AC analysis of CE amplifier in ltspice. Im getting error "Iteration limit reached" when adding resistor between emitter and ground. Im using bi component for current controlled current source with setting I=I(R1)*100. Why is this failing to simulate? Whats the correct way of doing it?I attached the schematic.

author: Kuba_eM
author_rank: Newbie
timestamp: February 13, 2020, 11:44:04 am
content: Should B1 parameter not be given as {I(R1)*100} ?

author: avogadro
author_rank: Contributor
timestamp: February 13, 2020, 12:07:39 pm
content: Quote from: Kuba_eM on February 13, 2020, 11:44:04 amIt works without those curly brackets, the problem is with the resistor R1, without it it works fine. Anyways I got it to simulate for lower values of R1 (like 20 ohm works). I wonder if this has something to do with the settings?

author: iMo
author_rank: Super Contributor
timestamp: February 13, 2020, 12:10:32 pm
content: Post your .asc file..

author: avogadro
author_rank: Contributor
timestamp: February 13, 2020, 12:26:08 pm
content: Quote from: imo on February 13, 2020, 12:10:32 pmHere it is.

author: Wimberleytech
author_rank: Super Contributor
timestamp: February 13, 2020, 01:38:56 pm
content: For whatever reason, it does not like the I(R1) expression. Use a voltage source with zero volts instead.<<update>>It converges if there is no multiplier while using I(R1).I have increased the iteration limit to 3000 (with gain of 100) and it still does not converge.Hmmmmm...

author: iMo
author_rank: Super Contributor
timestamp: February 13, 2020, 07:16:52 pm
content: Try with current controlled current source.F1 is the CCCS, controlled by the current flowing via V2, the gain=100.

author: Wimberleytech
author_rank: Super Contributor
timestamp: February 13, 2020, 07:29:48 pm
content: Quote from: imo on February 13, 2020, 07:16:52 pmI concur. The CCCS worked for me as well. I suspect that a current source with the directive I=I(V1)*100 will instantiate in the matrix just like and F element would.I am still puzzled why the original post does not work.

author: iMo
author_rank: Super Contributor
timestamp: February 13, 2020, 08:28:23 pm
content: @Wimberleytech: But you have got a typo in your schematics - the current is I(V2)*100.I think the F converts differently..

author: Wimberleytech
author_rank: Super Contributor
timestamp: February 13, 2020, 11:24:01 pm
content: Quote from: imo on February 13, 2020, 08:28:23 pmoops you are right. It still converges once I change it to V2.As far as how the matrix is instantiated...that was just a guess, but an educated one.When I run them together I get exactly the same result.
What am I doing wrong? - Page 1
Forum section: electronics / beginners

author: pkr
author_rank: Newbie
timestamp: December 01, 2015, 04:37:38 pm
content: I'm a bit new to this so I suspect I'm doing something wrong and I'd appreciate any pointers.I took delivery today of a Siglent SDG1020 to replace the cheap eBay special I already have. The problem is, it isn't behaving as I would expect.I've set a 30Hz square wave at 50% with 4vpp ( just playing about, the values aren't significant ) and my scope is telling me the signal is +7.4vpp with an offset -3.84v.Thinking the problem may be with the cheap scope*, I plug in the old generator with the same settings and I get on the scope what I expect! 30Hz, 4vpp, 0v min, 4v max, 50% duty.I've tried the 'Self Adjust' menu item with no difference and channel 2 produces a similar effect - although I can't set 4vpp on channel 2 ( SDG1020 limitation ).I naturally think that it's me doing something wrong but when I see a 4vpp setting and the scope is saying 7.4vpp there is an element of doubt that the SDG1020 is working properly.Help please! And apologies in advance if it's me being stupid.* and yes I've seen Dave's video about it and I know his opinion! A new one will be purchased in the new year

author: deephaven
author_rank: Frequent Contributor
timestamp: December 01, 2015, 04:48:29 pm
content: It says "load 50 ohms" so maybe you just need to terminate the signal with 50 ohms, otherwise it will be double what you're expecting. It might not be able to do the full 8V p-p which could account for the lower than it should be value.

author: grumpydoc
author_rank: Super Contributor
timestamp: December 01, 2015, 04:56:12 pm
content: deephaven is correct about the 50 ohms load although I would say it is much more likely that the toy oscilloscope is getting the voltage wrong.The sig gen will default to outputting a singal which is symmetrical around 0V so it will be swinging between -4V and 4V (or -2V and 2V if you terminate it into 50 ohms).

author: pkr
author_rank: Newbie
timestamp: December 01, 2015, 05:07:20 pm
content: I though I'd tried HighZ, but I was probably confusing myself by then. I'll try what that again.Thanks.

author: pickle9000
author_rank: Super Contributor
timestamp: December 01, 2015, 05:21:57 pm
content: Do some basics- Swap your probe leads and see if the dc offset changes.- Connect a 1.5 v batt to the scope and see what the voltage is, reverse the polarity and check again.- Place a cap in series with the signal in to strip off the dc.Any of these will help isolate if the scope is having an issue with the dc.If the scope has a cal feature do that before and after to see if there is a change.

author: fubar.gr
author_rank: Unknown
timestamp: December 01, 2015, 05:32:37 pm
content: Allan (W2AEW) has an excellent video on the topic:

author: pkr
author_rank: Newbie
timestamp: December 02, 2015, 03:07:03 pm
content: Thanks guys. It was indeed my problem but I've got my head around it now!I had seen another video about 50R & HighZ - a guy with a German/Austrian accent which explained it very well using an analogue voltmeter.Thanks again.
what am i missing? is this even possible? - Page 1
Forum section: electronics / beginners

author: superwester
author_rank: Contributor
timestamp: January 05, 2018, 03:39:08 am
content: so i need that a change in a voltage caused by a potentiometer to trigger a high logic level using an lm393.i thought this could be achieved by "delaying" the signal of the potentiometer via a resistor and a capacitor in series connected to the inverting pin of the comp. (just trying with one input of the lm393 for now).[see schematic attached]this isnt a solution right now. i cant find the right combination of resistance a capacitance to make this work, if they are too low the change isnt big enough to trigger the lm393 and if it is too big the voltage drop across the resistor and capacitor makes it always on.this analisis is all guessing because i dont have an oscilloscope to measure yet.if this is fundamentally wrong or you have any tips to make this work or just another solution and leave this idea please let me knowthanks in advance...W.

author: superwester
author_rank: Contributor
timestamp: January 05, 2018, 12:46:40 pm
content: im such a dumb ass...thank you!

author: Fludo
author_rank: Regular Contributor
timestamp: January 10, 2018, 12:01:32 pm
content: You will need some type of transistor or switch on the output. The LED is always on because it is receiving 5V from the supply at all times.