hybridfree/eevblog-posts huggingface dataset:
SWR LA 12 Bass amp inop. Powers on, only humms - Page 1
Forum section: electronics / beginners

author: 2222
author_rank: Contributor
timestamp: January 05, 2024, 12:19:16 am
content: SWR model LA 12 60 watt bass amp powers up but only hums (suspiciously like 60Hz?). A friend gave it to me to, thinking I might be able to fix it.One chassis attachment screw is missing, and others show marking that it has been opened up previously.At first it almost started to amplify a test signal, then it started thumping the speaker several times per second. When I powered it off it let out a squeal that rose in pitch until it quickly faded. Insides have a faint burnt electronics odor.I may have identified what looks like a dry solder joint at the (marked "+") leg of what is labeled BR1 (bridge rectifier?).Photos to follow.

author: 2222
author_rank: Contributor
timestamp: January 05, 2024, 12:24:08 am
content: Preamp photos

author: 2222
author_rank: Contributor
timestamp: January 05, 2024, 12:29:31 am
content: Power amp photosDetail of possible dry solder joint on BR1 "+" leg.

author: p.larner
author_rank: Frequent Contributor
timestamp: January 05, 2024, 01:16:30 am
content: maybe it doesent know the words to the songs?,couldnt resist that! lol.

author: 2222
author_rank: Contributor
timestamp: January 05, 2024, 01:19:28 am
content: Good one!
swr meter couplers - Page 1
Forum section: electronics / beginners

author: p.larner
author_rank: Frequent Contributor
timestamp: January 18, 2024, 02:35:31 pm
content: ive looked at a few hf swr coupler/bridges,some only use 1 torroid and some use 2 or 3 why is that?.

author: jwet
author_rank: Frequent Contributor
timestamp: January 18, 2024, 02:53:00 pm
content: Measuring SWR requires you to measure forward and reverse power. Forward power is usually measured as current with a 1:N transformer formed with a single turn signal going through a toroid with a secondary to give you a measurable voltage out- 10 turns is common. Reverse power can be sensed as voltage with N:1 transformer across the output using a toroid with N turns (enough to give an impedance >>50 ohms) to a N turn secondary (N usually 10-100 turns). Alternatively, voltage can be measured with capacitive divider on the output side- this saves a toroid. The two should be equivalent though the two toroid design is usually more broadband if done correctly. The ARRL handbook has good explanations of this as well as some projects. The name for the most common of these bridges is usually attributed to Breune- good Google search term.

author: p.larner
author_rank: Frequent Contributor
timestamp: January 18, 2024, 04:28:40 pm
content: i was more interested to know how its done with 1 rather than a few.

author: jwet
author_rank: Frequent Contributor
timestamp: January 18, 2024, 04:46:13 pm
content: It can be done with none if you sense current without a transformer. It will be quite lossy and probably only suitable for QRP application.

author: geggi1
author_rank: Frequent Contributor
timestamp: January 19, 2024, 07:52:50 pm
content: You should check out LA8AK (sk) web. It is still operational after more than 10 years of passing.He have made a description of a directional made of coaxial cable.https://www.noding.com/la8ak/m12.htmThe design is pretty genius with a low component count and no hard to get toroides,
SWR Video - Page 1
Forum section: electronics / beginners

author: WBB
author_rank: Regular Contributor
timestamp: November 19, 2012, 12:33:55 pm
content: Not sure if this has been posted before. Thought it was an excellent video, especially for those interested in RF and transmission lines. Enjoy!

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 19, 2012, 03:28:11 pm
content: Wonderful! And his subtle smile after each demonstration made me smile too

author: w2aew
author_rank: Super Contributor
timestamp: November 19, 2012, 09:28:13 pm
content: I saw this video a while back, and it is a really great way to describe wave propagation, terminations, and reflections on transmission lines. Brilliant!
Symbol for a line lag ??? - Page 1
Forum section: electronics / beginners

author: Vtile
author_rank: Super Contributor
timestamp: April 02, 2018, 10:11:55 am
content: HelloI don't know if this is that much a beginner question, but since the beginner section is the most Q&A place in eevBlog forums I ask here.I wonder is there a common (while not widely seen) drawing symbol for a general line lag, in electrical/electronics or in system design categories? Those old "memory lines" used in early computers comes first to my mind, but I would just to like to use it in topology drawings indicating a lag between nodes.I can't remember I have seen one, but that doesn't say that such wouldn't exist.-thx

author: Vtile
author_rank: Super Contributor
timestamp: April 02, 2018, 10:22:54 am
content: Quote from: blueskull on April 02, 2018, 10:14:53 amThx. I'm more interested in the natural routing (or cable or data transmission) delay than one clock delay. I need to check what I can find from signal drawing symbols, me thinks..... Ok, dead time symbolThank you, you cleared my head.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 02, 2018, 11:08:31 am
content: Transmission line.Tim

author: Vtile
author_rank: Super Contributor
timestamp: April 02, 2018, 11:16:17 am
content: Quote from: T3sl4co1l on April 02, 2018, 11:08:31 am.. but the transmission line (drawing symbols) doesn't have a separate symbol (as far as I can remember) for the transmission time as it is "default" feature of transmission line analysis as it takes account the wave length and c in particular medium.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 02, 2018, 11:37:03 am
content: What do you mean, "separate symbol"? The length (duration) and impedance of a TL are the parameters, just as a resistor symbol has a resistance parameter, or a capacitor has a capacitance parameter.Tim

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: April 02, 2018, 01:34:05 pm
content: If the system is represented as continuous time and in block diagram form, I suppose you would be able to use the Laplace identity of:f(t-a)*u(t-a) = exp(-s*a)*F(s) (Having a block that's just the exponential)Perhaps people don't use this in actual continuous time applications? I'm not too sure.
Symbol in IC schematic. - Page 1
Forum section: electronics / beginners

author: rqsall
author_rank: Regular Contributor
timestamp: July 10, 2015, 05:17:34 pm
content: Hello,I bought some LM1036 ICs at aliexpress. Fully prepared to take my loss if they turn out to be duds, which they seem to be. However, I would still like to take some measurements and see if I can open a dispute. Now, I'm trying to measure the resistance from the input to ground on it, and I measure open circuit while it should be around 30k, but in the schematic there's a symbol consisting of two circles overlapping partially between the 30k resistor and ground. What does that symbol represent?The datasheet is here:http://www.ti.com/lit/ds/symlink/lm1036.pdfThe schematic is on page 13 and I'm measuring between pin 2 and 10.Thanks for any input.

author: TimFox
author_rank: Super Contributor
timestamp: July 10, 2015, 05:21:33 pm
content: That symbol means a current source: the schematic simplified that to a basic symbol (probably two or so transistors and some resistors). With no power applied to the device, that source won't work and the measured DC resistance is not determined.

author: rqsall
author_rank: Regular Contributor
timestamp: July 10, 2015, 05:28:33 pm
content: Thanks, was just about to answer my own question, because I discovered the 160uA and 220uA values next to some of them. Then googled "current source symbol" and found it.So I guess I can't determine it this way. Reversing the polarity of the resistance measurement (positive probe on ground pin) gives me 24kOhm and .9V when set to diode. I guess I'm just doing something wrong.Thanks again.

author: rqsall
author_rank: Regular Contributor
timestamp: July 10, 2015, 07:53:34 pm
content: Well, I found out my error. Since I'm lacking some pots, I had just made voltage dividers for the volume, treble, bass and balance controls. "Raising the volume" helped a little.Also providing a 50ohm resistor to ground at the input to match the 50ohm output impedance of the function generator helped even more. Turns out Mr. Baba sent me working products after all
Symbol <---> Footprint assignment in KiCAD - Page 1
Forum section: electronics / beginners

author: eamoex
author_rank: Contributor
timestamp: January 28, 2021, 08:21:57 am
content: Hi, I'm laying out my first circuit in KiCAD. The circuit is not from me, it is an audio filter circuit which I modified for it to take stereo signal.The audio inputs and outputs are in the shape of TS mono jack, and these are correctly represented in the schematic. Because all jacks and pots will be panel mount rather than PCB mount, I'd like them to actually be screw terminal blocks on the actual PCB.Now my problem is this: when I update the PCB in Pcbnew with the netlist, I get errors pertaining to the names of the pads on these terminal blocks. I can very well see that the pad names are different in eeschema and Pcbnew, but I can't find a way to get rid of these errors. I've edited the PCB footprint pads to change the pad names so they match the ones in eeschema, but it doesn't help. Plus the rastnet from these connectors to their connected components doesn't show.What am I doing wrong? Thanks!

author: ve7xen
author_rank: Super Contributor
timestamp: January 28, 2021, 08:33:20 am
content: As far as I know there's no way to create a 'pin map' in Kicad (5 at least). The names of the pins in the schematic symbol need to match directly with the names of the pads in the footprint. I hope this is on the roadmap, because it's annoying for any part that comes in different packages.In this case, you need to create a new footprint in the footprint editor (just load the library one and save it in a different library / with a new name) and change the pin names there (or do the same with the schematic symbol if that makes more sense to you). An alternative would be to not include the a jack footprint at all and just manually add the terminal block footprints in pcbnew, attach the pads to the appropriate nets, and route them, but I'd consider this sloppy because it's no longer tied to the schema. You could also put both on the schema. Some old electronics did this, depicting the board connectors wired to the off-board component in a dashed box or that sort of thing.

author: eamoex
author_rank: Contributor
timestamp: January 28, 2021, 08:38:11 am
content: Thanks a lot. I'll be trying this out. I might post back with results.

author: eamoex
author_rank: Contributor
timestamp: January 28, 2021, 10:24:57 pm
content: Beautiful, editing a copy of the footprint did it! The footprint now generates the correct rastnet.Another thing that was misleading is the fact that in the footprint editor, when you double-click a pad to modifiy its properties, the field for its name says "Padnumber" — and so it isn't obvious you actually can put analpha characterthere (the jack connector symbol usesTandSfor Tip and Sleeve). More so if, like me, you don't as yet understand the topology of this CAD environment very well.Thanks again
Symbol question - Page 1
Forum section: electronics / beginners

author: Chipmunk
author_rank: Contributor
timestamp: March 31, 2015, 09:10:23 am
content: I noticed in reviewing the sample chapter from The Art of Electronics that the USAnian electrolytic capacitor symbol doesn't look remotely like the European standard one I grew up with... I'm also aware of course of the 'big rectangular block' vs 'zigzag' resistor symbols... I wonder if anyone knows of any others that could be misinterpreted? (or similar convention differences that cause problems)
Symbol similar to the diode - Page 1
Forum section: electronics / beginners

author: Jasonbit
author_rank: Regular Contributor
timestamp: February 24, 2019, 05:36:59 pm
content: Hello folks,What means this symbol?https://snag.gy/qWxdJO.jpgThanks

author: edgaras006
author_rank: Contributor
timestamp: February 24, 2019, 05:42:05 pm
content: ESD diode or surge suppressor.

author: Cubdriver
author_rank: Unknown
timestamp: February 24, 2019, 05:43:15 pm
content: Bidirectional zener diode.-Pat

author: exe
author_rank: Unknown
timestamp: February 24, 2019, 07:24:16 pm
content: I know it as a TVS diode.

author: Jwillis
author_rank: Super Contributor
timestamp: February 25, 2019, 11:44:32 pm
content: Bidirectional Avalanche Transient Voltage Suppressor Diode
Symetrical/Geometrical PCB Layout - Page 1
Forum section: electronics / beginners

author: raw-electrons
author_rank: Newbie
timestamp: September 18, 2015, 03:44:00 am
content: I'm playing around with kicad and working on my first-ever project. Since it's my first project, I'm sticking to a fairly simple LED blinking circuit. However, to make it interesting, I've decided to arrange some LED bargraphs in a circle (well, more like a pentagon, but you get the idea). Only one of these components lines up with a the grid, the rest are at regular and predictable angles. Additionally, it seems to make sence to allign the traces to this formation, rather than creating awkward stepping 45 degree traces. I've done this by hand, but the results don't look all that regular.My question is: Is there a way to place components in some kind of symetrical way? anything other than free hand mode?And to follow up on that, are there any limitations for "weird" angles which a PCB manufacturer will balk at?

author: BradC
author_rank: Super Contributor
timestamp: September 18, 2015, 05:44:37 am
content: I've done odd designs in AutoCAD and imported the dxf into Altium before to use as alignment and snap-to markers. There's probably a way to to it in Altium, but I'm more conversant in CAD so this was quick and easy for me.

author: katzohki
author_rank: Frequent Contributor
timestamp: September 18, 2015, 05:40:35 pm
content: Altium has a way of specifically making patterns like that, but since you're using Kicad, I don't know. Maybe it has the feature? As for your PCB guy, I guess you just have to ask what he thinks. Some PCB manufacturers are better than others.

author: Rerouter
author_rank: Super Contributor
timestamp: September 19, 2015, 11:28:47 am
content: Simplest way is to spend 5 minutes with a calculator,In a footprints properties, you can specify the X position, Y Position and the rotation in 0.1 degrees, so you get the picture, you work out the points, then edit the parts to reflect those points,
Synchronous boost converter problem. - Page 1
Forum section: electronics / beginners

author: step_s
author_rank: Regular Contributor
timestamp: May 02, 2016, 10:15:23 pm
content: Hi EEVblog.I'm currently messing around with a synchronous boost converter design for 5V, since the high side diode is a major source of loss when running low voltages, but I've run in to some problems.The design is very simple, and looks like thishttp://www.dtmassociates.com/Power%20Page%20Info/Converters/SBoost.gifI'm running the mosfets from a PIC with the CWG module, so I i can control the deadband rise and fall times.The problem I'm having is, that when running the low side mosfet alone, the design works as intended, and the booster runs well, but when trying to connect the high side mosfet, the system comes under heavy load (2A). I have a schottky diode across the high side mosfet.The design is soldered in a protoboard, very thick tracks, and the PIC is on a breadboard.I have attached an oscilloscope reading from the design. The green wave is from the switching point (directly between low side mosfet and coil) when the low side mosfet is running, and the yellow is the intended high side gate drive (when not connected). I have adjusted the deadband delay so that the high side will only turn on when the switching point is high, and then turn off in time for the switching point to go low again.The system is running 500ma of load while I'm doing this to prevent the coil from being depleted. It's at around 7V output.Any thoughts and ideas on how I can test this?
Synchronous Buck Converter Designing - Page 1
Forum section: electronics / beginners

author: Nithis
author_rank: Newbie
timestamp: December 20, 2024, 03:16:08 pm
content: I tried designing a Synchronous Buck Converter following a tutorial on YouTube as a preliminary step to present to my professor, showcasing basic learning of circuit design for a project. However, I encountered an issue where the current flowing through the MOSFET is excessively high during the switching period, as shown in the attached diagram. I’m quite confused about what might be causing this issue, how to resolve it, and whether my initial design is okay (other performance aspects, such as Voutput and the current flowing through the inductor, align with my calculations).

author: Slh
author_rank: Regular Contributor
timestamp: December 20, 2024, 04:07:00 pm
content: The pulse on turn off is the reverse recovery of the anti parallel diode. The (smaller) pulse on turn on is the output capacitance of M2 charging up. If you're only after a few amps output then the MOSFETs that you've chosen might be a bit on the large side.Incidentally, an annoying thing about spice simulation is that the reverse recovery is only partially modelled so reverse recovery losses are higher than your simulation will suggest.

author: Konkedout
author_rank: Frequent Contributor
timestamp: December 21, 2024, 12:33:51 am
content: It might also be non-overlap dead time.In the simulation, you could try adding a schottky diode in parallel with the low side MOSFET with cathode to drain. That might prevent your drain body diode from conducting so prevent diode reverse recovery if that is your problem. Note that in hardware, even a tiny amount of layout inductance between the schottky diode and the low side MOSFET prevents it from working well. That is why the FETTKY (FET with integrated schottky diode) was a thing for a while.Nowadays I think that controller ICs focus on getting the non-overlap dead time right.

author: Nithis
author_rank: Newbie
timestamp: December 21, 2024, 04:49:53 pm
content: Quote from: Slh on December 20, 2024, 04:07:00 pmThank you very much. What you’ve answered has helped me to continue my research and better understand how the circuit works. I’d like to ask just a little more. So, it seems that the current spike from reverse recovery can’t be completely eliminated, but it can only be reduced to an acceptable level (by using a diode with low trr and low Qoss), right?

author: Slh
author_rank: Regular Contributor
timestamp: December 21, 2024, 05:33:44 pm
content: With MOSFETs, the only thing you can do is optimise more for switching so you'll probably end up with a higher r_ds(on) MOSFET with a faster diode for M1. So yes the spike can't be eliminated, only reduced.A silly question, are the losses excessive at the moment? Perhaps you can live with it at the current level.
Synchronous Buck Converter Problem - No Power (AP62301) - Page 1
Forum section: electronics / beginners

author: dindondee
author_rank: Contributor
timestamp: January 11, 2023, 06:27:12 pm
content: Hello,I designed a PCB with the AP62301. Everything is assembled and there are no shorts. To test the board, I supplied 7V @ 1.3A from the PSU to the AP62301 but there is no 5V on the board.To troubleshoot, I measured the voltage across the PSU input on the board because the PSU says some power is being consumed and it reads 0V. I thought that was odd so I removed a resistor to leave the EN pin floating and flipped the inductor, still no power. I also varied the current to the board with no luck. At this point I have no idea what the problem could be. Attached is a picture of the schematic and layout, I appreciate any help with this. Please let me know if you have any questions, thank you!

author: Wolfram
author_rank: Frequent Contributor
timestamp: January 12, 2023, 03:08:16 pm
content: QuoteIf you're measuring 0 V across the input of your board, the first step is to find out why. Unless the board is drawing excessive current and collapsing the voltage of your external PSU, there must be a broken connection somewhere between the PSU and your board.Where is R41 on your PCB? I don't see anything pulling up the EN pin voltage. I guess it could be on the underside of the board, but the EN pin signal has no visible vias.

author: mvs
author_rank: Frequent Contributor
timestamp: January 12, 2023, 09:03:32 pm
content: R41 = 3.3k and R43 = 2.2k would set Von=2.994V and Voff=2.727V. This values are under min values (Von>=4.15V and Voff>=3.85V) specified in the datasheet under equations Eq 4. and 5. on page 14.With floating EN pin this converter should start, but internal pull-up is very weak (1.5 µA). You may have some contamination on the board that pulls EN pin to ground. If you wish to stick with default 3.6V UVLO - use R41 as external pull-up (around 10k - 100k) and leave R43 empty.
synchronous counter help - Page 1
Forum section: electronics / beginners

author: christos10
author_rank: Contributor
timestamp: December 27, 2014, 10:37:16 pm
content: hello,,i have a project i need to make for school,,i need to make a synchronous counter that counts 3-7-8-2-3(4 digits),,i need to use T flip flops(j-k)i just need some ideas to start workingthx
Synchronous IR beam break detector for outdoor use with indirect sunlight - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: October 12, 2016, 01:16:04 pm
content: I couldn't find any info on how commercial systems work so by trial and error I have arrived at the following system which uses a pulsed IR LED and photodiode.Below is my current algorithm.With the LED transmitter off, take multiple measurements of the photodiode current for 100 milliseconds, calculate the average background current and peak to peak noise.Pulse the LED (1 millisecond) and measure the photodiode current.Subtract the previously measured background current.Divide the result by the previously measured peak noise current to give the signal to noise ratio.Compare this to some threshold value.Is this how commercial systems work?Developing indoors where there is little ambient IR and testing outdoors in constantly changing conditions is a real challenge.Mike

author: bobaruni
author_rank: Regular Contributor
timestamp: October 12, 2016, 01:40:05 pm
content: The way some beam break detectors work is by transmitting a modulated signal (square wave) and receiving the signal and only amplifying the AC portion of the signal though AC coupling, this eliminates the effects of ambient light.In essence, the method you have described will work almost the same as AC coupling the signal, take care you have enough headroom (low enough gain so as not to overload in direct sunlight) in your trans-impedance amplifier.

author: e100
author_rank: Frequent Contributor
timestamp: October 12, 2016, 02:41:20 pm
content: Quote from: bobaruni on October 12, 2016, 01:40:05 pmAs I was stepping into the unknown, I went with DC measurements so I could detect if the ambient light was overloading the receiver. By luck it seems that I have about 50% of the dynamic range left when outdoors.Indoors the ambient is virtually zero and the signal to noise is about 3:1.Weather permitting I'll do some more outdoor tests tomorrow.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 12, 2016, 03:07:12 pm
content: In principle the suggested method is ok. However they tend to use a faster sequence and one should also average over more pulses. So more like a 10-100 µs pulse every 1-10 ms.The difference might also determined in an analog way.
Synchronous motor driven from stepper controller?  - Page 1
Forum section: electronics / beginners

author: Bootalito
author_rank: Unknown
timestamp: November 23, 2017, 12:08:20 am
content: Is it possible to drive a small synchronous motor from one of the commonly available stepper drivers? Assuming that the synchronous motor is rated for 24vac, and you're feeding the stepper driver 24vdc. I'm also assuming that you would need to configure the stepper driver for no microstepping? Perhaps the uC code would need to alternate direction between steps to produce a sine wave?
Synchronous motors questions - Page 1
Forum section: electronics / beginners

author: GoatZero
author_rank: Regular Contributor
timestamp: October 16, 2013, 08:12:37 pm
content: i have been reading about synchronous motors, and i actually got one from a microwave , i was playing around with it and suddenly when i was spinning the propeller i got shocked, by touching the terminalsi pulled out a multimetter to meassure voltage in CD and CA and both are getting generated, (way more CA than CD)so now i wonderWhy is this happening?Is it generating AC or DC ?Whats the max voltage i can get from spining this thing ?I have to go out i will plug it to an oscilloscope later tonight however i wanted to ask so maybe someone gere can give me any leads of why is this happening

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 17, 2013, 04:52:50 am
content: it's a 120v motor rated for 6 rpm.it will generate AC, at a pretty high voltage, put your multimeter on it in ac, stick it in a vice/vise and SLOWLY spin the shaft with your hand, and then with a drill to see what kind of voltage you get, you might be surprised.

author: sleemanj
author_rank: Super Contributor
timestamp: October 17, 2013, 05:43:37 am
content: Quote from: GoatZero on October 16, 2013, 08:12:37 pmAsk yourself the question"what is the difference between a motor and a generator".

author: amyk
author_rank: Super Contributor
timestamp: October 17, 2013, 10:54:28 am
content: Quote from: peter.mitchell on October 17, 2013, 04:52:50 amI wouldn't advise the latter - this looks like a geared motor with a very high reduction ratio (designed for 6RPM out) and pushing it much beyond that has a high chance of breaking something.

author: Zero999
author_rank: Super Contributor
timestamp: October 17, 2013, 12:41:09 pm
content: That's exactly why he said slowly.It's not only the gears which could be a problem, if you spin it too quickly, the output voltage could be too high for the insulation, causing it to arc over.

author: SeanB
author_rank: Super Contributor
timestamp: October 17, 2013, 06:46:10 pm
content: As it is a synchronous motor it has a permanent magnet on a shaft. Turn the magnet and you make a changing magnetic field in a coil of wire, which generates a voltage. Slightly different construction is used to make an alternator like in your portable genset, but the principles are the same.
System disk HP 1652b - Page 1
Forum section: electronics / beginners

author: Henk4free
author_rank: Newbie
timestamp: April 16, 2016, 10:41:36 am
content: Hey,I'm looking for a system disk for an HP 1652B logic analyzer.I know the software "LIFUTIL" but whit a DD disc he always gives "track 0 error"can anyone help me?Regards, Henk

author: mettlerr
author_rank: Unknown
timestamp: April 17, 2016, 03:21:47 am
content: Hi HenkI think maybe the problem is, that LIFUTIL needs direct BIOS access to write to a floppy in LIF format. All the new OSes (from Windows 2000 onwards) do not allow direct BIOS access from a command line box, but Windows 98 and below would.What OS are you trying to write the disk from?
System stays on even after turning off master battery switch - Page 1
Forum section: electronics / beginners

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: May 30, 2025, 04:40:10 pm
content: You can see the wiring diagram from my previous threadhere. Mine in the OP and someone's improvements below.As I didn't need to show the switches when I was orignally making the diagram I didn't add them as it was not pertinent but there is a master isolator switch between leisure battery to positive busbar and another. This was supposed to turn off the whole system, which it does usually behave as expected but there have been a couple of occasion, today being one, where the system stays live even after the switch has been turned to the off position.The power I guess it still coming through the solar. I think it may be related to the dc-dc charger? because it was acting screwy in itself and when I took the negative fuse (yest I said it right it is a negative fuse!) then the system turned off and when I threw the isolator switch again it turned off the system as it should.I am wondering if it is because the circuit between dc-dc charger/starter battery is still making a full circuit? I wonder why this behaviour is not usually noticed though and the issue is intermittent?Oh as I mentioned the dc-dc charger was playing up for some reason, very temperamental it is. I hadn't even run it for months but I had switched the system off and when I switched it back on again the charger was jammed with the fan blasting away and not going into sleep mode like it should after a few seconds of starting up.That happened one time before and didn't figure out why but just took the fuse out and put it back in again the next day or so and it worked again. Somehow doing factory resets doesn't even affect it and it would only stop that after the aforementioned.So any hypotheses on how the solar could continue to power the system in this case? Maybe the dc charger being stuck on meant the connection circuit was made whereas usually it wouldn't behave like that if in sleep mode.

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: May 31, 2025, 12:13:24 pm
content: Is there any wiring diagram?

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: June 20, 2025, 06:14:18 am
content: It is in the first line of the post...
Sziklai pair power series pass setup - Page 1
Forum section: electronics / beginners

author: sahko123
author_rank: Frequent Contributor
timestamp: April 01, 2020, 12:13:51 am
content: All i want to know simply, is a sziklai pair with say a generic pnp transistor with a tip3055 power npn acting as a negative pass element possible or should i just get the complementary tip2955? This pair will be used as a negative voltage regulator.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 01, 2020, 12:19:59 am
content: Yes.Tim

author: sahko123
author_rank: Frequent Contributor
timestamp: April 01, 2020, 01:28:41 am
content: as amazing as the answer was where the sign-off takes more characters than the answer could i know to what question it was addressed? What i essentially want know is does sziklai pair essentially change the type (npn/pnp) of the transistor regardless of power.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 01, 2020, 02:41:46 am
content: You asked if it's possible, or some alternative; yes, it is absolutely possible, so no alternative is needed. You hadn't indicated what else you're lacking, so...The type of the Sziklai pair is defined by the input transistor, yes. The input transistor only needs to be rated for the base current required by the output transistor, and both need to be rated for operating voltage and power dissipation. Some typical caveats include potential for oscillation, and proper design of current limiting or other protective means.Oscillation can happen for a combination of reasons: the input transistor is typically rated for less current and more fT, while the output transistor has a lower fT, longer lead lengths and higher capacitances; this introduces more gain and phase shift in the C-E path of the input transistor, which can push the combination into oscillation. Whereas a Darlington has Miller effect (C-B feedback) and emitter degeneration (the one emitter is cascaded into the next base).Note that an emitter resistor on the output transistor essentially accomplishes nothing. If an emitter resistor is used for degeneration or limiting, it goes on the composite/equivalent emitter terminal. Which is obvious when drawn with the equivalent/composite, but it's been missed before...Tim

author: David Hess
author_rank: Super Contributor
timestamp: April 01, 2020, 02:59:35 pm
content: Before good and economical silicon power PNP transistors became available, it was more common to use Sziklai pairs for negative regulators and for the negative side of class-AB audio power amplifiers. Search for "quasi complementary power amplifier" to find examples.
T Flip-Flop with Negative Edge - Page 1
Forum section: electronics / beginners

author: 2X
author_rank: Frequent Contributor
timestamp: March 17, 2019, 09:53:57 pm
content: Hello, does anyone knows if there is any part number of a chip with T Flip-Flop with Negative Edge Clock? Thanks in advance.

author: edavid
author_rank: Super Contributor
timestamp: March 17, 2019, 10:14:33 pm
content: 74HC112/74VHC112 is the only one I know that's still in production.

author: 2X
author_rank: Frequent Contributor
timestamp: June 08, 2019, 07:10:00 pm
content: Thanks for the reply but these are JK Flip Flops... Does anyone knows a code even if it is not still in production? Maybe I will find a used one on ebay.

author: JxR
author_rank: Unknown
timestamp: June 08, 2019, 07:32:27 pm
content: Quote from: edavid on March 17, 2019, 10:14:33 pmQuote from: 2X on June 08, 2019, 07:10:00 pmAll you do is tie J and K together to make a T Flip Flop. So, the answer above is probably your best solution.
T parameters of a two-ports circuit - Page 1
Forum section: electronics / beginners

author: Nexo
author_rank: Regular Contributor
timestamp: June 03, 2018, 12:45:35 am
content: Hello everyone!I just finished my third exam and I know I won't get a good grade so I'd like to know how to correctly solve this problem:I'm asked to find the T parameters of the circuit shown in the attachment.1. I know that A is in parallel and I already did that part; well, I have the Z parameters and I was thinking about finding the Z parameters of B as well because A and B are in series so I could just add them up and then transform it into T parameters ¿is this a good approach or what would you recommend?2. How should analyze the B part of the circuit? some friends said that there are 3 two-ports in series but I can't seem to figure it out.Anyy help will be very much appreciated.Thanks in advance!

author: Nexo
author_rank: Regular Contributor
timestamp: June 03, 2018, 08:40:33 pm
content: Anyone, please? I just need ideas, not actual math.Thanks in advance!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 03, 2018, 10:28:33 pm
content: I think you need to do the T of both, then multiply them together. I forget the rules for Z, but if adding works then yeah, that too.I don't get the crossover in B, it's just there to confuse... just use whatever (matrix or wye-delta?) reduction you want to solve that with.Tim

author: Nexo
author_rank: Regular Contributor
timestamp: June 10, 2018, 06:24:14 am
content: I've already solved and I'm going to post the photos next week. Thank you very much!

author: The Electrician
author_rank: Frequent Contributor
timestamp: June 14, 2018, 02:58:45 am
content: Quote from: Nexo on June 03, 2018, 12:45:35 amWhat did you get for the Z parameters for part A? And what do you get if you transform to T parameters?You can't get the overall Z parameters by adding the Z parameters for the A and B parts separately.

author: The Electrician
author_rank: Frequent Contributor
timestamp: June 19, 2018, 12:38:01 am
content: I'm going to be disappointed after going to the trouble of working out a solution if you don't come back and show your results.

author: Nexo
author_rank: Regular Contributor
timestamp: September 01, 2018, 07:32:42 pm
content: I'm so sorry for not posting before, I was really really busy with a lot of stuffs, I'm goint to solve it again because I lost the pages on which I had the answer and post it.

author: The Electrician
author_rank: Frequent Contributor
timestamp: September 01, 2018, 09:15:19 pm
content: I'm looking forward to seeing your result.

author: The Electrician
author_rank: Frequent Contributor
timestamp: September 27, 2018, 04:54:07 am
content: Did you get lost again?
T-shooter - Page 1
Forum section: electronics / beginners

author: Carioca10
author_rank: Unknown
timestamp: January 29, 2021, 10:52:48 pm
content: Hello there!I bought an old book “Troubleshooting for Electronics” from Albert Paul Malvino.It came with a floppy disk and this software “T-shooter”.Unfortunately my PC floppy disk reader is no more functioning.I notice that previous editions of “Electronic Principles” the author also used it for.Could anyone please note me kindly where I could download it and if possible with installation instructions?Regards,Felipe
T12 Control board - Fledgling tinkerer needs peace of mind. - Page 1
Forum section: electronics / beginners

author: Oxidised Tool
author_rank: Newbie
timestamp: April 05, 2023, 11:13:34 am
content: Hi to everyone. I recently purchased a T12 control board from Ali and noticed it doesn't ground the tip in the graphic. All wires connect to + or -Is the graphic correct? Am I missing something?https://ae01.alicdn.com/kf/Hd932ae3277c144e6bbba845f3d6cf532P.jpgThanks.

author: DavidAlfa
author_rank: Super Contributor
timestamp: April 05, 2023, 03:54:33 pm
content: You can ground it as required.My advice is to use a high value resistor, like 10k-100K, that should discharge any static, but prevent it from blowing up if touching live wiring for whatever reason.In fact most ESD stuff (Mats, cushions/foams, bracelets) are in the Mohm scale.

author: floobydust
author_rank: Super Contributor
timestamp: April 05, 2023, 06:51:38 pm
content: Best to hard wire ground the 24V secondary side, including the tip. pichttps://www.eevblog.com/forum/beginners/t12-clones-and-grounding/msg3412134/#msg3412134Using a high value (1MEG) resistor did not work here:https://www.eevblog.com/forum/dodgy-technology/dangerous-solder-station-ksger-t12/msg3960062/#msg3960062It depends on the quality of SMPS transformer winding, but 1MEG still allowed high voltage to the tip ~30-40VAC.ESD wristbands and mats use 1MEG for static dissipative but don't work with a Y-capacitor and high frequency pulses as a source.
T12 solder station, 4 or 5 wire irons - Page 1
Forum section: electronics / beginners

author: NickRNott
author_rank: Newbie
timestamp: June 17, 2018, 08:23:25 am
content: Hello all.I still use an Antex 25w iron I bought decades ago for a class I took. Now that I have some time I thought to upgrade and buy a 'new technology' DIY kit from Aliexpress. It's ridiculous how cheap some of these stations are and the most important bits are all in the T12 cartridge.I'm quite excited to see that the modern irons have micro controllers and PIDs. It might be a nice way to learn about programming mcu's. Watching EEVBlog vids will do that to a person.I'm struggling to choose a kit that will still be compatible with open source firmware that I can tinker with. PTDreamerhttps://github.com/PTDreamer/stm32_soldering_iron_controllerhas written firmware for a KSGER OLED controller based on a STM32F103C8T but the KSGER boards have gone from version 1 to version 3 before he could properly finish. I have no idea if anybody will bother to adapt it for the new boards.So now I'm stuck. Any advice?Also I'm confused about the difference between the 5 wire and 4 wire irons. I know there are heater + & -, earth, and then thermistor/thermocouple and 'shake to wake' switch. But both handle types seem to have the same features.

author: exe
author_rank: Unknown
timestamp: June 17, 2018, 02:40:50 pm
content: Yeah, purchase decisions are difficult. I used to be in the same situation with T12 stations. While I can't answer all your question, I can answer some of them.1. Version 2.1 vs version 3. Rumors say KSGER's v2.1 stations run outsorced firmware for which the seller pays something. Version 3 is the same hardware, but with a completely rewritten firmware to avoid paying to the software developer. It's hard to find a good comparison, but people say firmwares are mostly identical, but 2.1S was more polished (as of a few months ago).2. Is updatable firmware really needed? I have 2.1 station that "just works". I don't feel like I want to replace/upgrade firmware.So, my advice: go for proven 2.1S with a shake sensor. The sensor works really great on my station, it's not like an encapsulated ball with spring contacts, it really detects motion (I'd say it's even too sensitive). I bought a complete kit in metal enclosure and I'm happy with it. It's really cool (or "hot"?), fast and compact. Beware it doesn't come with handpiece stand.Just check tip ground connection when it arrives, I heard someone had issues with this and for some reason (bad SMPS?) the tip was at ~115V potential. So, worth checking.

author: Hergen Lehmann
author_rank: Newbie
timestamp: December 21, 2018, 12:05:26 pm
content: Quote from: NickRNott on June 17, 2018, 08:23:25 am5wire irons have an additional temperature sensor in the handle to allow for proper cold junction compensation. However, i'm unsure how well this is implemented in the firmware. At least the 3.0 firmware continues to show a menu item to manually enter a temperature, which does not make sense, if there is a sensor for that.
Korad has been working fine Except…. - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: September 30, 2013, 07:27:24 pm
content: I really like this new power supply. Everything has been work fine on it, except I still can't figure out the OVP. The over current protections seems to work fine. I have been going through the Make Electronics book, and I'm on chapter 7. Got tired of alligator clipping everything together, and started breadboarding the projects. That was pretty easy till I got to the relay stuff. Figuring out what contacts need to be isolated with the by the center channel on the board takes some getting use to, especially since I had to figure out the layout from clips to breadboard myself, but got it working on the second try!
How to choose the µC/OS for ST32F103RET6? - Page 1
Forum section: electronics / beginners

author: rozeh
author_rank: Regular Contributor
timestamp: November 08, 2013, 04:10:45 pm
content: Hey guys,I have a ST32F103RET6 MCU and want to choose the µC/OS for it but, when I go to µC/OS'sweb-site, I see for Some MCU like:STM32F103RBandSTM32F103VBandSTM32F103ZEI don't know which is for my MCU! and also I have another problem. my Compiler is Keil but, sound like it just support the IAR.

author: Hideki
author_rank: Frequent Contributor
timestamp: November 09, 2013, 12:08:42 am
content: The first letter after 103 indicates the number of pins: R (64 pins), V (100 pins) or Z (144 pins).The second letter indicates the amount of flash: B (128k), E (512k).The third is package type and the fourth is temperature range.Many other combinations exist. Seehttp://www.st.com/web/en/catalog/mmc/FM141/SC1169/SS1031/LN1565If that doesn't help, ask Micrium for help... (or maybe pick a free compiler and RTOS?

author: rozeh
author_rank: Regular Contributor
timestamp: November 09, 2013, 04:55:09 am
content: Thanks Hideki,I'd like to use µC/OS, not RTOS.I think it is the best.

author: Hideki
author_rank: Frequent Contributor
timestamp: November 09, 2013, 12:55:31 pm
content: µC/OS is an RTOS, so I don't know what you mean by that.

author: rozeh
author_rank: Regular Contributor
timestamp: November 09, 2013, 01:24:58 pm
content: Quote from: Hideki on November 09, 2013, 12:55:31 pmI meanFreeRTOSbut, I think it was a mistake.
T48 and 25Q128FV problem - Page 1
Forum section: electronics / beginners

author: Crina64
author_rank: Newbie
timestamp: August 31, 2024, 05:43:55 am
content: Hi all and sorry for my bad English.To program Bios chips I have used, sometimes, a CH341 but due to slowness or random errors in read/write, I decided to buy a T48 (without adapters).Now I need to program a 25Q128FV (notebook bios) using a Pomona clip but the T48 can't do it and I get an error.Do I need an adapter to do it? Can't I use Ziff directly via clip? I hope you can help me.Thanks

author: Crina64
author_rank: Newbie
timestamp: August 31, 2024, 01:52:04 pm
content: I finally solved itby removing the 25Q128FV from the pcb and programming it directly with the T48, without using the clip.It worked perfectly.
t68-2 ferrite torroids - Page 1
Forum section: electronics / beginners

author: p.larner
author_rank: Frequent Contributor
timestamp: January 06, 2024, 09:45:21 pm
content: can t68-2 torroid cores be used to wind the coils on for an hf diy stockton bridge?,ie 3-30 Mhz

author: ZigmundRat
author_rank: Regular Contributor
timestamp: January 07, 2024, 03:46:22 am
content: It should. Keep in mind that as a powdered iron toroid, it takes more turns per micro(milli)henry than the more typical 43 ferrite. For example, the K3NG tuner uses 40 turns on a T50-2 in its bridge.

author: p.larner
author_rank: Frequent Contributor
timestamp: January 07, 2024, 02:39:43 pm
content: thanks,some experimentation req i think then.73
Reprogram an onboard  Nordic Semiconductor. Nordic’s nRF51822 Bluetooth SoC - Page 1
Forum section: electronics / beginners

author: vdiallonort
author_rank: Newbie
timestamp: May 31, 2016, 01:28:55 am
content: Hello,I am not an electronic engineer but i still have basic skill ( did my bachelor in Telecommunication ) and I would like to know how hard it will be to reprogram an Nordic Semiconductor. Nordic’s nRF51822 Bluetooth SoC that is inside my Basis Peak watch.I like to connect to other remote sensor and create my own feature. I am guessing it will be by far different than when I reprogram my onboard Arduino. But does there is interface I can use the same way than with my Atmega chip ?Vincent

author: jnz
author_rank: Frequent Contributor
timestamp: May 31, 2016, 03:57:10 am
content: The chips are easy to reprogram, as iirc, nothing locks the Jtag out. Although I have no idea if your board makes this easy.But what you are saying is you want to add your own feature, but you'll need to entirely start over with the firmware. You'll need to get the Nordic SDK and a development enviroment, chart out their hardware, make the headers for that board, and start programming.You'd be doing almost all the work to create a marketable Nordic powered BLE device. The interface is the absolute last concern IMO.

author: vdiallonort
author_rank: Newbie
timestamp: May 31, 2016, 04:04:34 am
content: Thanks,not sure how far i want to go, for now it's only studying and the pure love of learning.I am "just" ( can be a lot of work ) looking to get the raw information from the sensor and send them by Bluetooth to my computer.But since I will not be able to de-compile the existing firmware,I will have to find out how all the sensors works,protocol and how they are wired.Vincent

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: August 05, 2016, 07:07:45 pm
content: Did you ever give this a go? Now that that peak isbeing recalledand support discontinued, a hack like this would be be the only way to continue using it.

author: electrostorm
author_rank: Newbie
timestamp: June 15, 2017, 04:18:08 pm
content: I've been able to re-program my nrf51822 based fitness tracker using the Arduino IDE. Being Arm based, the nrf51822 works with most Arm compatible Arduino libraries.Using a $3 St-link V2 from ebay.http://www.ebay.com.au/itm/1PCS-ST-Link-V2-Programming-Unit-mini-STM8-STM32-Emulator-Downloader-AU-NEW-/302095788532?hash=item46564fe9f4:g:ePAAAOSwbPxXQCccI disconnected the battery from the tracker connected the board's GND and Battery terminals to St-link V2 GND and 3.3V pins. Also pins 23 and 24 which were exposed as pads on my board and easy to connect to SWDIO and SWDCLK pins on St-link V2https://devzone.nordicsemi.com/question/1010/programming-pins-of-the-nrf51822-chip/Install sandeepmistry's Arduino board manager and flash SoftDevice firmware to the nrf51822 with the Arduino IDE . This wipes any previous firmware and installs BluetoothLE functions.https://github.com/sandeepmistry/arduino-nRF5Next I have to get the OLED display working,,