**raises hand** - but understand; most smart people are on the spectrum to some degree. Part of autism is - generally speaking - I/O processing abilities that neurotypicals cannot even comprehend, let alone actually accomplish. ;)
Not to mention: The ability to print right past the bottom of the page with no margin. Remember when you could print a banner on any old printer and not have to tape together 17 sheets?
Mmmm... Memories of elder times... Formaline we used to call those tear-off strips with holes that fed into the tractors. And the striped paper 132 or 148 character wide I think, 48 lines long unless it was the "Yankee-format". That paper had pink stripes, not blue, and 72 lines if I remember correctly. At least ours did. Did a lot of off-line printing when I was young. Running six big bulky Sperry Univac line printers fed by, would you believe, Datapoint 2200-series computers and stand alone tape stations. Then came the lasers and the fun went out of it.
Hours of “fun” when a fan fold dot matrix line printer ends up with misaligned paper and the toothed drive wheels shred the edges of the paper... Or when something disturbs the output pile and it then settles down folding the paper the wrong way round... but you have to sort out the resulting mess!
Hey! I've used fan-fold printer paper at home! 😂 Oddly enough, I have a photo of my daughter (now 21, then about 3) on my cork board, printed with a dot matrix printer on fan-fold paper.
When placing components onto a board, if you spread the legs of the component slighty it will hold itself to the board without falling out making it much easier to solder.
Handy tip ( ? ) .... when taking apart discarded microwave ovens ( for all manner of useful stuff ) , there is almost always a FREE filter board near to the cable inlet ( this will save you £ 2-55 ! ! ) ... FYI a ( brittle ! ) magnetron magnet can be stuffed onto a wood broom handle with a plastic spray can top screwed into the end of the handle ( this protects the brittle magnet from knocks ) ... MOST USEFUL to pick up dropped steel wood screws / drill bits / nails from your floor / DRIVEWAY ( tried - n - tested ) ....
You explained the common-mode choke filter backwards. In normal operation the two windings cancel each others flux out thus giving a very low impedance. When in common-mode filtering they work together to create the high impedance to the high frequency noise signals.
Definitely check that common mode choke because sometimes cheap ones from China are made of aluminum and just coated to look like copper, and it will have quite different characteristics than an actual copper choke.
All the control devices at work use the screw connectors. I lost track of how may intermittent faults have be traced back to someone installing the wire under a clamp. I always tell the guys to turn the screw backwards until it clicks which indicates the screw is all the way down. At the lowest point the screw is out of the clamp and it is not possible to put the wire under it.
I might be a little late to the party, but for what you do on your channel, I couldn't suppress a little snicker when you said you misidentified the MOVs for some Y-CAPs at first...😂😉
If your washing-machine is going berserk when it goes into spin mode, it's probably wearing out its bearings and, regrettably, will soon have to be replaced. The big washing machines you find in dry-cleaners have self-balancing drums, but the ones sold for use at home just rely on ballast, typically big lumps of concrete.
It's not too bad. It will try to balance the load repeatedly sensed by slow spinning to detect the motor feedback pattern. If it fails to balance awkward things like heavy overalls it will try for a while with various untangling techniques including snatching the drum round briefly and then give up and not do the final spin.
You could add 2 x 68 K 0.6w resistors giving 136 K from live to neutral for discharge in an insulator to keep it safe. If my maths are right it gives about 15 dB filtering at typical switchmode frequencies. 20 dB would be better. The common mode choke might be 2 mH. If so plenty. Slightly above 20 dB if so. Assuming 50 ohms reference as is typical.
My guess, and it is pure speculation, as I'm a mere EE, not anywhere NEAR your level, mind you, but my assumption on why IET still uses those old 1-sided screw terminals is abuse. I've seen some INSANE jobs people have done (ask me about the bullets used as crimp connectors in every switch/outlet of a house I rented, and why that was one of the LESS dangerous issues I fixed while living there!) and the amount of rough handling stuff gets. Especially once you get away from larger city areas, you end up with the only certified electricians being farmers who just do that on their spare time for extra money. Some of them are great. Some... couldn't care less, and just want the money. That little skirt/apron thing (I can't recall the term either) is slightly flexible and springy. I can't imagine it would withstand too many over-tightenings of it using power tools (again, I've replaced a number of fuses that were stripped out this way on the back because they were clearly installed using a drill - had to tap-mount them out using a dremel and reverse-bit. What a pain). But yeah, I'm guessing it's a liability thing. If they recommend something people CAN break, followed by lawsuits, of course, because that's the default go-to of modern society, it will happen. Unfortunate, but the probability is pretty grim. I would assume it's because of this. No matter how many times you choke down those old bite-y screw ones, they'll always perform at the same level. Might not be a GOOD level, but it's consistent and durable. Anyway, just my guess there. Might be completely off track, but I figured I'd post it anyway. Also, and I'm sure most people will laugh at this, but THANK YOU for lining up the 3rd capacitor. I can't even DESCRIBE how twitchy I was starting to get from the point you said you don't care and aren't paying attention 'til you placed it, as I was DREADING it being "backwards" (to my perception only). Especially when 2 of 3 were already perfectly aligned like that. (I try to make my boards NOT look like I bought them of Alibaba, preassembled by a drunk chef who hates his job, and is wondering how he went from holding a carving knife to a soldering iron.) Yes, I'm well aware it doesn't matter whatsoever. Still bugs my OCD, or "touch of autism" as Clive put it (I love it!).
I still have some fan fold printer paper. Both the plain white kind, and one that is blue and white stripes with 3 blue lines, 3 white lines, 3 blue lines, etc. :-D
Dear Clive I recently let the smoke out of my DIY PC power supply bench supply. So it is time to build another , would you do one and put your special spin on it for inspiration and suggestions ?
I have one of these filters but it doesn't have any connection to earth on it. It would have been nice if you had explained how important caps are where the movs were. I'm going to guess so if you see a rather red sunset in the East from where you are - it's me.
Recently had the same discharge issue with a BBC Master switched mode psu. The switching has stopped working due to dodgy cap and to3 transistor. just built a full charge into the 250v caps as there was no load and i "snapped" it across my fingers.
Big Clive (as others have done) has just driven off of the road into the ditch. Homes and industry present a largely inductive (positive reactance) load on the power suppliers. (because of things like Clive's washing machine) Items like this and LED lamps with capacitive droppers (negative reactance) partly counter the existing positive reactance, they do NOT create a bad reactance. This talk about being charged for apparent power is a big dud. Ron W4BIN
About cutting the lead too short: 12:36 "Not to worry" 13:07 "Not to worry. I'm not bothered." 15:57 "I'm not too bothered by that." (It's really bothering him lol!)
Hmm, fan-fold printer paper, yes .... also like punched paper tape sprocket holes! From the days when bugs were wildlife which may cause your software to fail. :-)
I worked with fan-fold paper in the 80's. Use to print bank statements on high speed metal belt printers which meant a full box of paper didn't last too long. Always great fun when the paper wouldn't stack again on exit from the print mechanism and you had to hand fold the paper without tearing or getting dirt on it. And we also used punch cards for program initiation and daily parameter changes. Oh the good old days.
Hours of “fun” when a fan fold dot matrix line printer ends up with misaligned paper and the toothed drive wheels shred the edges of the paper... Or when something disturbs the output pile and it then settles down folding the paper the wrong way round... but you have to sort out the resulting mess!
Ya I have checked a lot of things and on several things with compressors i have improved the power factor with a capacitor across the compressor just because and because i am working on doing some off grid stuff but like my xbox and Samsung tv are around a .6 power factor which is bot great but i have a cheap 65 inch tv in the living room and it is like .98 or something real high which is surprising because its cheap
There's going to have to be a radical redesign of electrical devices.Right now too many electronics are drawing microamps on standby mode.Dave Jones at eevblog just did a video about how much power something as simple as smoke detectors are eating up.
@@james10739 A lot of the big TV's are coming with built in power factor correction these days even the cheaper ones, the PFC designs are becoming more standardized and use an IC, MOSFET and inductor (basically a boost stage timed with the mains waveform before the big DC filter capacitor).
@@chaosflower4892 Depends what the price of power is in your local area, what provider you're with, what particular price plan you're on, even what time of the day.
Getting the parts orientated in the same direction *isn't just about aesthetics* but actually makes circuit checking and diagnoses so much easier when you don't need to turn the board around, etc. It is a good habit to learn.
It also helps when it comes to odd noises and interferences generated due to imbalances in the circuit. It becomes an even greater concern at the microchip level, where the distances are much smaller.
A common mode choke works in the opposite manner that you showed; the fields cancel with normal differential AC current flow, and the fields add in the case of common mode current.
@@stargazer7644 I'm with Tyler on this. The fields add in the case of common mode current. This creates a magnetic field, and that very field opposes the flow of the current which created it. That's how I understand inductance to work. I think it's Lenz's law.
Or to put it more simply, any induced magnetic field causes a corresponding EMF (voltage) which opposes the current flow. With this application, the mains current produces two different magnetic fields each of which has the same strength, hence they cancel one another out, so no resulting EMF.
I was going to comment on this. He had the concept right, but was wrong about when the inductance "activates" as it were. And of course, those chokes can be wired as differential or common mode, and in a few COTS EMI filters (Corcom etc) there is one of each, although differential mode is usually accomplished with two inductors not coupled for some reason I have had too little coffee this AM to recollect... also, printer paper: I got to use actual teletypes in the USAF. I'm not that old, our site was slow to get updated hardware. I was shocked when I got there in 1981 to see 1950s comms, 1960s compute and 1970s crypto. O_O
Your magnetic flux flow is wrong. When the magnetic fluxes oppose, they cancel and the inductor does nothing. This is the normal operation. When the magnetic fluxes add it has inductance that oppses the current flow. This is the state that attenuates a common mode current.
I thought that was wrong too. If current flows in opposite directions the field should cancel so inductance is small, common mode the field will add so inductance is large.
I once got shown a “circuit board” as used on an oil refinery control system. They didn’t use electricity they used air. The board was two plates bonded together. The “traces” were tubes embossed between the plates. Capacitors were implemented using tiny bellows. Resistors were little Venturi. I can’t remember all the details (this was early eighties) but it still amazes me.
@@geoffreykeane4072 Many appliances in EX (explosive hazard) atmospheres run on compressed air indeed. There's a whole range of sensors, regulators, and actuators run entirely on the flow and pressure of not electrons but good old bellows stuffing. I worked with them in chemical industry myself. Fun stuff.
OH NOOOO! Genuine Rifa capacitors - the scourge of old test equipment. Hope they have changed the type of plastic used for the outer shell. Great explanations of common mode choke and X cap function. Thank you Clive.
The choke explanation is the wrong way round, though. It's the induction from common mode noise that is _in_ phase; the induction from regular LN AC is out of phase.
@@Mark1024MAK Nooooo! I just had one fail (missed it during inspection after purchase) in an HP 4262A LCR meter. I had to remove all cards and clean them and the chassis to get rid of the stink. There was this yellow film.................
David V - some 1980s computers are renowned for their old Rifa X2 capacitors going pop and filling rooms with their distinctive horrible smell. If you don’t clean up any of the gunk that gets on a nearby heatsink, it will continue to stink every time it is on long enough for the heatsink to heat up....
I'm 37, but it was only ~10 years ago we ordered a dot matrix printer with form feed for a customer who had tens of thousands of pre printed fanfold double layer carbon copy invoice forms they wanted to keep using... It was not a cheap printer...
I think your explanation of the common-mode choke is the wrong way round. It should be that, if the current is flowing in the same direction in both wires, the magnetic fields add to each other, requiring a magnetic field to be built up, which makes the choke act like an inductor. And if the current is flowing in different directions, the magnetic fields cancel out, so the choke doesn't act like an inductor.
When my brother did his high school work experience at the computer shop I was working for..... First job we had him do was hook up an old dot matrix printer, load some tractor feed paper, and run a DOS program I'd written that printed out his list of tasks for the week... I had intentionally introduced a short pause between every character to make it print slow, so it took about 10 minutes to print... Which is roughly how long it took him to figure out how to feed the paper in.
Clive, any chance you could do an ELI5 of power factor or "power factor for dummies" type video? Or maybe just as a side note in any given video? The term comes up a lot, and I understand that it's a comparison of apparent vs. real power, but I think some of us could benefit from a simplified explanation of WHY there's a difference in apparent and real power and where it comes from.
For me as a newbie to electronics this was absolutely fascinating. I just loved the explanation as to how the circuit worked with the components and also your analysis of the components used. Love your channel. :)
I was about to comment the same. Where the magnetic fields from the windings cancel there is no impedance and therefore no power dissipation in the choke. If they add (common mode) you get impedance.
@new name As I understand it, under normal circumstances the field created by each coil cancel each other out and hence produce no back EMF as the voltage rises and falls. If noise is introduced, the difference between the fields in the inductor will be the effect of the noise. This magnetic field as it rises and falls will induce a back EMF opposing the very voltage that caused it.
There is only one thing you need to learn about lead-free solder: A _good_ joint made with lead-free solder looks _exactly the same_ as a _bad_ joint made with lead-free solder.
That common mode choke would also take the edge off of choppy modified sine wave AC, which can make audio equipment annoyingly buzzy. Though I don't know how much edge it would take off, doesn't seem like it has a very high inductance. It would still do something though, as the inductance of the choke would resist the sharp voltage(current) rise of a stair stepped waveform to some degree.
It won't have much effect on audio equipment. Common-mode chokes really only affect noise in the range 100kHz through 30MHz, which may help reduce audible noise on an AM radio or a SW radio.
There seems to be enough combined reactance - although some series independent inductances would be very helpful - to significantly reduce the hash from ubiquitous cheap phase angle dimmers, the bane of HF / DX radio operators / listeners the world over. They and other industrial hash are why many hams choose to move to the boonies to pursue their hobbies. Most houses, and certainly all businesses, street lights, etc, etc, are hella noisy both in radiated and line conducted noise.
Clive! I have a replacement mainboard coming for a fancy inverter/solar/charger/battery/etc unit... Are you interested in the old one? It's doing some strange things... 😉
13:36 - "I was going to describe it as like fan-fold printer paper but none of you knows what that is unless you're very old..." Hey!! I'm only 44 and not only do I remember it, I used it growing up! Since when is 44 "very old?" Sheesh! ;)
Much more could have easily gone wrong: 1) Clive cuts a new slot in his fingettip with that nice new nipper. 2) Clive puts the first connector terminal block in backwards (he only checked when he got to the second terminal block). 3) Clive didn't burn himself. 4) Clive didn't zap himself when holding the pliers against the charged terminals. (You can't count on a pliers joint to be nicely conductive, and remember, you are holding both metal sections of the pliers.) BTW, the standard way of soldering discrete components is to insert them, hold them snug and straight, arch the wires slightly on the far side of the board and then position the board for easy access of the iron and solder. This holds the component while you solder the joints. Finally, trim the excess component leads.
Having the skirt at the bottom of the clamp is a nice feature. Had a set without those little aprons and lost track of how many times I've screwed one of the terminals down and then the wire just falls right out.
That's how we learned to solder: Start with phone connectors, then go quickly to 5 pin + DIN connectors to solder on wires. The process then is a combination of swear, hate and soldering. But in the end you know how to solder.
Every time Clive mentions the bandoliered components, I wonder if a dot matrix printer could be modified to feed pieces into a diy automatic soldering system. I think this is the first time I've heard him reference fanfold paper, though...I can't even begin to think of how many boxes of it I must have bought back in my early computer days. Suddenly I feel like I'm ancient. Thanks Clive! 😆😆
i do too. I work as a lab equipment repairman, and lab equipment boards are notorious for having inadequately tiny pads connected to inadequately thin tracks, that together with inadequately narrow holes in the pads and the use if these pads as free vias makes replacing blown components a true nightmare.
why not flip all the components to the other side of the board? that would put the actually soldered pads on the correct side also.... might be messier... but stand the components up off the board.... add tiny tubing to the legs.... and solder on BOTH sides im not a pro at electronics.... im more of a mechanic.... but i know enough to get myself into trouble but I!! dont see anything wrong with flipping the board over.....and all they need to do is put the printing on the other side, and its "perfect"
You botched the description of the magnetic field directions in the core and when they cancel and when they don't. You got the relative phasing of the two windings backwards. One of the windings, lets say the bottom, induces magnetic fields in the opposite direction as what you show. If you look closely, while it goes around the core in the opposite direction when looking at your diagram, it also is going in the opposite direction around the cross section of the core. The two opposites cancel out. For differential signals, the magnetic fields cancel each other out so there is no inductance. There is no "circulating magnetic field", as you say in the video, in that case. For common mode signals, the magnetic fields add to each other so there is significant inductance to help block the signals. So, rather than fighting as you say in the video, the magnetic fields are going in the same direction and reinforcing each other.
When I first saw you solder that way I thought "so, I'm not the only one that does it that way." Now based on your comment at 14:05, maybe it is weird.
I still have a printer 🖨 that uses “Fan Fold Printer Paper” with the Perforated Tear Off Sprocket Hole Strips attached to the edge of your 8.5”x11” Sheets of Printer 🖨 Paper 📝!!! All zigzag/fan folded into a stack of paper folded up inside a box to be able to let the pages feed into the printer while leaving the paper in the box 📦 Vs. now where most people take the paper out of the packaging and set it into a paper tray inside the printer 🖨 !! Loading rollers were crap 💩 back then!!! ;)
If the soldering life and neutral on the wrong side bother you, you could just populate the board from the designated solder side, it is symetric. Furthermore, to get a ‘thicker’ earth connection just add solder to the non-screen-printed copper on the PCB.
The wide area in the earth conductor provides shunt capacitance from the two x2 capacitor to earth. I do not know what the capacitance line to ground is, but it is a clever circuit trick!
Very old, me. Speaking of fan fold- There was a live stream a few years back where Tom Scott and crew printed the comments from a live stream and fed the result directly into a shredder. I do wonder how many viewers had ever seen a dot matrix printer before.
When you said, "good enough," you reminded me of Steven Lavimoniere (RU-vid) saying, "It's good enough for this neighborhood, mama!" He's a plumber by the way.
Company I work for still uses industrial dot matrix printers and fan fold paper for invoicing, I have the joy of listening to them screeching away in the next room every night.
It's nice to see a cameo appearance from Alice1101983! The clearance (or lack thereof) between the traces and screw holes is quite concerning... I miss fan-feed dot matrix printers... Somewhat. Sure, they were noisy as heck, and slow, but the ribbons were cheap and the printers had some actual weight to them. I remember my ImageWriter II used to cause the table it was on to shake during printing.
I do envy your finger dexterity - something I once had as a young technician. Age and chemo have a way of damaging the nerves in one's fingers. I use various clamping devices now to prevent finger cramps more than to hold things for soldering, but after a 40 year career in electronics I'm thankful I'm still in the game. I could have used this power filter kit 30 years ago when computers were much more sensitive to transient spikes.
Using MOVs between neutral, ground, and hot is pretty common in the USA inside of cheap power strips that claim to provide protection against power spikes. They are sacrificial, and I don't know how much of a voltage spike they can withstand before letting the magic smoke out.
