This $0.70 Component SAVES your Circuit?! (Surge Protection) EB#59

Ғылым және технология

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In this electronics basics episode, we will be having a closer look at overvoltage/surge protection components. Now a voltage surge only occurs rarely through lightning, inductive switching in your grid or an electrostatic discharge. But if they hit your electronics, they can immediately destroy them. But with the 3 shown components you can easily and for pretty cheap save your circuits. Let's get started!
Thanks to Mouser Electronics for sponsoring this video.
0:00 Overvoltage Problems!
1:25 Intro
2:08 Creating an Overvoltage Pulse for Testing
3:37 Test Circuit for the Experiment
4:04 Protection 1: TVS Diode
7:24 Protection 2: MOV
9:45 Protection 3: GDT
10:27 Comparison between all
10:47 Difference between Cheap/Expensive Surge Protection

Пікірлер: 411

  • @Alacritous
    @AlacritousАй бұрын

    I had lighting strike the radio antenna of a cellular remote oil well monitor that I had built a long time ago. It skipped right over the lightning arrestor on the antenna cable and blew the ground track off the entire circuit, through the cellular modem, through the serial cable connecting the modem to the PLC, through the PLC circuit board, through the ground wire and into the electrical circuit on the engine skid that was supplying power to the automation panel. Was a hell of a thing. The ENTIRE circuit from top to bottom vaporized. There was nothing left of the tracks at all.

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    That sounds scary. Thanks for sharing your story :-)

  • @awesomecronk7183

    @awesomecronk7183

    Ай бұрын

    "Well shit"

  • @Alacritous

    @Alacritous

    Ай бұрын

    @@greatscottlab Well, it didn't happen while I was standing next to it. I got a call saying the install wasn't powering on. Remote trouble shooting didn't turn up anything so I had them pull the unit and send it back to me. I took it apart and found dust and vaporized copper.

  • @MrWaalkman

    @MrWaalkman

    Ай бұрын

    What brand of PLC? That's not something that you see happen to a PLC very often. The problem with voltage protection is that it's like walking under the hoover dam with your umbrella open. You should be good, right?

  • @ExploringNew1

    @ExploringNew1

    Ай бұрын

    Gosh

  • @PhilipKloppers
    @PhilipKloppersАй бұрын

    I repair control circuits for some industrial equipment, and they regularly use both a TVS diode and GDT in parallel on each line. The TVS diode handles the lower voltage transients, while the GDT protects against higher incidents like lightning surges. It works very well, and it's easy to test and cheap to replace if it does blow.

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Thanks for the feedback. Good to know.

  • @orclev

    @orclev

    Ай бұрын

    Hearing the way each device worked that was my immediate thought "can you use them in parallel to protect against a wider range of voltages?". Good to hear I was on the right track.

  • @ryanshea5221

    @ryanshea5221

    Ай бұрын

    If they're in parallel, couldn't a high voltage transient just take the TVS line? I'm still learning this stuff

  • @orclev

    @orclev

    Ай бұрын

    @@ryanshea5221 So, electricity always takes the path of least resistance (more or less). Think of each of these devices as a conditional short, it's normally not shorted to ground, but under specific sets of voltages it triggers a short, at which point IT becomes the path of least resistance, and so the voltage spike will take that path rather than flowing through the higher resistance (sensitive) circuit. Each device has a limited range of voltages and response times it's good for, past a certain point it will fry (or under a certain point it won't trigger), stop conducting, and then you're back to the circuit you're trying to protect being the path of least resistance which you don't want. By putting a bunch of them in parallel you're covering a wider range of potential voltages, and even if multiple of them get fried, it's cheaper and easier to replace these components than the rest of the circuit.

  • @haakonness

    @haakonness

    Ай бұрын

    a TVS failing would mean that it does not conduct to ground, so a parallell device that also conducts to ground during a high voltage transient, would take over. Or what did you mean by "take the TVS line"?

  • @iamdarkyoshi
    @iamdarkyoshiАй бұрын

    Here's a video idea: Signal integrity When and how to use shielded wires, coaxial wires, differential twisted pairs, ect and avoiding issues like ground loops (like connecting the shield only on one end) ect

  • @ameliabuns4058

    @ameliabuns4058

    Ай бұрын

    Yess. And things like 50 ohm terminations and signal reflections

  • @iamdarkyoshi

    @iamdarkyoshi

    Ай бұрын

    @@ameliabuns4058 Oh yeah, definitely!

  • @ameliabuns4058

    @ameliabuns4058

    Ай бұрын

    @@iamdarkyoshi although I think Scott's area of expertise is high voltages and mains stuff? so he might not be the best person for this as much as I love the way he explains things.

  • @teardowndan5364

    @teardowndan5364

    Ай бұрын

    Based on his stair light PCB layout, running small-signal traces parallel with the PWM-regulated unfiltered LED power traces with the two LED power traces routed about as far apart from each other as possible for maximum EMI, I doubt Scott knows anything about signal integrity. He'd certainly gain a lot from at least looking into the basics.

  • @ameliabuns4058

    @ameliabuns4058

    Ай бұрын

    @@teardowndan5364 well that could be phrased less harshly but yeah.

  • @SkyhawkSteve
    @SkyhawkSteveАй бұрын

    When designing automotive type electronics that had to meet EMC standards, the electronics had to withstand ESD discharges up to 15kV. Something as simple as a 1000pF cap at the input was often sufficient protection. Signals that couldn't tolerate that much capacitance were good candidates for a TVS diode. For power line transients, which are much longer in duration and contain much more energy, a larger TVS was usually the solution (perhaps in a SMB package). The datasheet will tell you how much energy a TVS package can handle. MOV's weren't used, and I get the feeling that they are more oriented towards mains power where lightning strikes are a risk.

  • @demetrisswest
    @demetrisswestАй бұрын

    Varistors are way slower than TVS diodes and aren't fit for fast transients such as ESD & EFT. Another thing to remember is Kirchoff's law, any current pulse will return to its source. Therefore instead of trying to suppress a pulse it is often more practical to divert it from the sensitive components using spark gaps etc

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Thanks for the feedback :-) Maybe I should have included spark gaps as well. Well, I will find space for it in another video.

  • @Kalvinjj

    @Kalvinjj

    Ай бұрын

    Seen a park gap do it's job in practice once (that is, after the fact not during it), on my TV's power supply. The comment I talk about it in case you wanna read: kzread.info/dash/bejne/f66spKSRoMrdoqg.html&lc=UgydNWuE3TvVqRYRkm94AaABAg The board does have an MOV there too I assume to protect against lower voltage surges instead of just lighting strikes or such high voltage stuff. Those two in combination sure did their job.

  • @ecstazyrm

    @ecstazyrm

    Ай бұрын

    Spark gaps still leave residual overvoltage which needs to be handled. They are also not suitable for a low transient range. Neither are repeatable or reliable. Mov and tvs coupled with esd suppressor is the way to go.

  • @paulgupta2454

    @paulgupta2454

    Ай бұрын

    Is a tvs diode not an esd suppressor? ​@@ecstazyrm

  • @muhammadawais7288

    @muhammadawais7288

    Ай бұрын

    @demetrisswest What is the path of current in TVS in case of ESD. when circuit is not connected to anything. can u explain a little please.

  • @YuNherd
    @YuNherdАй бұрын

    these should be compiled to a playlist "things i should have known before starting electronics". this is a huge lifesaver. good work as always.

  • @axelBr1
    @axelBr1Ай бұрын

    "Doesn't happen often that lightning strikes near you." I live in Singapore and I've had a thunderstorm every afternoon for the last three days. Yesterday the lightning strike was so close you could hear the crackle before the bang. But at least the humidity stops you getting static shocks from the carpets in the office. Something you might be able to advise on is the problem that I have, which is when there is a lightning strike nearby my RCD trips, none of my neighbours seem to be affected. I've always thought it was because I have an induction hob and the coil is picking up the EMP from the lightning and creating a current flow in the neutral line, as normally the hob is switched off at a wall switch, (which I assume only isolates the live), and hence causing a differential L to N current flow. You could probably have used an electric fencing unit to create a known and constant voltage, or a car ignition circuit.

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Thanks for the feedback. That sounds scary. And there I think overvoltage protection is a bit more important :-)

  • @raylopez99

    @raylopez99

    Ай бұрын

    @@greatscottlab Yeah when I lived in SE Asia my UPS would last a few months before bulging from an overworked battery due to a lightning strike They never lasted longer than a few months. Plus, aside from Singapore, a lot of countries in SE Asia don't use ground. I added a ground for a house we built, not sure how reliable it is for a big short or overvoltage, but at least it seems to work according to the multimeter.

  • @axelBr1

    @axelBr1

    Ай бұрын

    @@greatscottlab Nearly all power lines in the country (not that it's very big) are buried so I don't think that over voltage events occur very often. I've never had of over voltage protectors on domestic distribution boards.

  • @albertlagerman

    @albertlagerman

    Ай бұрын

    One time lightning struck pretty close to my Mom's house. My brother got a small shock from the wired headphones he was wearing (plugged into a PC which was grounded). It also tripped a GFCI. Not sure why it tripped, I just chocked it up to high voltage doing funky things.

  • @KnightsWithoutATable

    @KnightsWithoutATable

    Ай бұрын

    I lived in Florida, USA for a while. Lightning happened every other day. I lost a computer motherboard to a cable modem conducting a lighting strike from the cable system into it and thine through it into the computer because the lightning arrest system on the building failed. My next computer had optically isolated I/O ports and my replacement cable modem's coax went through a surge suppressor, as did the LAN cable that came off it, isolating any future lighting strikes from the network and my new computer with three layers of protection.

  • @SuperLordstein
    @SuperLordsteinАй бұрын

    As a notebook repairman, I am very familiar with diode arrays, it is very common to find them protecting the USB, HDMI and other connectors on the boards, many versions of notebooks for home use differ from the corporate versions in that although they have the tracks, They do not have the chip installed, this small saving makes the notebook much more delicate, plus now all those connections go directly to the SOC, system on chip, practically killing the processor in the event of any incident.

  • @R.Daneel
    @R.DaneelАй бұрын

    I'm familiar with GDT as a "Comgap". As in communications gap. Back in the landline days, they were a required component (in Canada at least) across tip and ring on a phone line. Every modem had one for example. It was to supress lightning strike level voltages from reaching the consumer. If it happened to protect a circuit, that was just a side effect. They were often used in combination with a MOV. Old-school rotary phones generally didn't need them as the ringer coil would take the punishment instead.

  • @daviddavidson2357
    @daviddavidson2357Ай бұрын

    9:37 Quick correction, that isn't a thermal fuse, it's just a standard electrical fuse. A thermal fuse is tripped when the temperature of a component gets too high. For example on motors to stop the windings from burning, electric heaters to stop your house from burning, hotplates to stop the hotplate from burning and so on. The resettable thermal fuses are usually found on components like electric heaters, hotplates, dehumidifiers and other devices, though are a first line of defense, they reset after the temperature drops (though microcontrollers have taken their place in some applications) but they'll also be found as second line of defense devices on industrial electronics (or higher end consumer stuff) where you have a uC and temperature probe (thermistor or thermocouple) monitoring the temp, but if the uC crashes, the resettable thermal fuse cuts the circuit, then if that fails a thermal fuse (attached using thermal paste) blows, giving the device 2 chances to recover and one chance to need fairly simple repairs.

  • @shreeneetrathi304
    @shreeneetrathi30423 күн бұрын

    This might be one of the most practical ESD - TVS based circuit protection video! I mean there are so many nuances of using TVS diode, routing them to the ground plane, ensuring low inductance to ground etc. This video gave me practical insight into the core fact that TVS diodes convert the ESD events into heat - boom seeing it practically save the circuit - made my day.

  • @GalgoczkiAdam
    @GalgoczkiAdamАй бұрын

    Thank you for the video! The MOV surprised me in this experiement, I didn't expect it will protect against sparks due to its slower reaction. I designed an off-line converter with an LNK-304 and lacked the mov. When my father plugged in a washing machine to the nearest socket the IC blown away. Never lack the MOV!

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Thanks for the feedback :-)

  • @dr.robertnick9599
    @dr.robertnick9599Ай бұрын

    A thing I like to do to protect low current inputs is a high value series resistor and a capacitor to gnd behind it. The resistor limits the current and the capacitor just eats the charge, so there is nothing left that the internal protection can't handle. Great for button inputs, as this also covers debouncing or acts as a low pass for "slow" analog inputs

  • @winlose3073
    @winlose3073Ай бұрын

    One of the most useful channels on YT thanks GreatScot this is really a great video.

  • @maticnovak2557
    @maticnovak2557Ай бұрын

    Hi GreatScott. Good video! I would like to add a few things: 9.44 the fuse in series with a varistor that you have drawn is not a thermal fuse, but an ordinary fuse, which would open when a varistor is damaged due to a high surge current. A thermal fuse is usually added in series to the varistor, so that if a varistor gets damaged and it conducts some small current it gets slowly hot - in that case a thermal fuse would open. some manufacturers even include a themal fuse in a varisto case, so the varistor has 3 pins. But you mentioned that the fuse blows when¸ an overvoltage event takes place, which is wrong. this would be a terrible design. actually we have to choose fuses, which have a high I^2t rating so that they DON'T blow during expected surge events. Your testing is only with ESD pulses, for which TVS diodes are best. Varistors and GDTs are used for surge pulses (indirect lightning strikes and inductive overvoltage events) which contain much more power. the 8/20us pulse is a typical indirect surge testing shape, which has 8 us of a rise time and 20 us of duration. there is also 10/1000us which has much more energy. ESD protection and surge protection are very different things. Usually for surge protection we use several of these protection components. for example we start with GDT, then varistor and then with the TVS diode. All three seperated with an inductor. Current and voltage on the device gets smaller with every component. 11.46 this is a thermal fuse and it opens when the varistor gets hot. the failure mode of a varistor is that with every surge pulse it conducts more leakage current. and when this leakage current is smaller than the current fuse in series, the varistor gets very hot and it ca cause a fire. that is why standards determine there has to be a thermal fuse there, which opens when varistor gets too hot. then it is time to change the protection module. Note that an ESD pulse has a rise time of 1 ns and duration of approx 50 ns. But a surge pulse has a rise time of 8 us and duration of 20 us or more. The problem with varistors is that the current through the device is increasing quite slowly with voltage rise. But a TVS diode's current increases much quicker with increasing voltage. at 7.58 you drew the correct V/I characteristic. but when you dig in a datasheet you see that the current rise in varistors is very slow. For example the varistor you showed MOV-20D681K conducts 1000A at 1600V and 1A at 800V. so it need additional 800V to get from 1A to 1000A. Usually a varistor is not used as a ESD protection device. I think it protected your circuit due to varistors parasitic capacitance, which conducts ESD current and not really due to the varistor voltage limiting.

  • @stevebabiak6997

    @stevebabiak6997

    Ай бұрын

    You used the term “power”, but “energy” is a better term for these discharge events.

  • @maticnovak2557

    @maticnovak2557

    Ай бұрын

    @@stevebabiak6997 true. Usually I’m checking max peak power capability in datasheets at a specific pulse time.

  • @paulgupta2454
    @paulgupta2454Ай бұрын

    Love this. Been researching ESD protection options and came across TVS diodes recently. This video really sold me

  • @s0ygecko
    @s0ygeckoАй бұрын

    Wait a moment... That isn't ElectroBoom job?

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    He didn't do this video topic yet. So I had to do it ;-)

  • @s0ygecko

    @s0ygecko

    Ай бұрын

    @@greatscottlab when a collab? Or is too much a trip on German hotels?

  • @superslash7254

    @superslash7254

    Ай бұрын

    @@s0ygecko Forbidden on grounds of safety.

  • @SimonBauer7

    @SimonBauer7

    Ай бұрын

    ​@@s0ygeckothe only things that will trip are the RCDs...

  • @s0ygecko

    @s0ygecko

    26 күн бұрын

    @ElectrBOOM can reclaim his job? 🤣

  • @DavidMulligan
    @DavidMulliganАй бұрын

    Thank you for this video, i love almost every video Great Scott produces. MOVs are commonly used with a few other components in AC power supplies such as class Y capacitors. I would love to see these covered in similar videos. Please and thank you.

  • @firenyth
    @firenythАй бұрын

    This video is really helpful. I suffered a power spike a couple years ago when the transformer outside my house blew up. lost a few appliances, namely my robot vacuum, looking at the board there were large scorch marks and some exploded components, after some research I discovered it was a varistor. easy enough to replace and still working to this day

  • @perperNorbi
    @perperNorbiАй бұрын

    Nice video, very informative. There is one thing I was missing. When adding such a protection to your pcb, you should pay attention to your layout and routing. You must route your wire through the pads of the tvs/mov to get the best results. And ideally they should be close to the connector.

  • @StoneFlange
    @StoneFlangeАй бұрын

    I never knew about transient voltage suppression components. Thanks for walking us through-it was very interesting!

  • @JesseGrunewald
    @JesseGrunewaldАй бұрын

    Thanks for another clear and informative video Scott

  • @brianwood5220
    @brianwood5220Ай бұрын

    Great video, Scott. Packed with loads of interesting info. Thanks for sharing.

  • @ChristieNel
    @ChristieNelАй бұрын

    It's very educational to have all of these in one video. Well done.

  • @iurlc
    @iurlcАй бұрын

    Good video. I want also mention, for low speed input lines often simple ceramic capacitors are used to protect the input from ESD loads. Usually 10 to 100nF are used.

  • @moeburn
    @moeburnАй бұрын

    I built a home energy monitor using CT clamps, and I learned they incorporate a TVS diode inside the clamp. Because without any load on the other end of the clamp, the 100A of current on my main line running through the core can generate theoretically millions of volts, and the whole thing just explodes in a puff of smoke without even touching any metal wires. I learned about their existence because I didn't understand any of this and unplugged my CT clamps from their load while current was running through them. The TVS diodes did their job, shunting the voltage to I think 22 volts, and making a hell of a racket, both noise and vibration, while they did so. Both clamps were unharmed and continue working accurately to this day.

  • @martinchabot_FR
    @martinchabot_FRАй бұрын

    When using a MOV on high side of power supply, you need to take account their failure mode: slowly conductive. So either couple them with thermal fuse close to them, or a combo MOV+ThFuse, or you can end up with a fire event in case of repetitive surges.

  • @Kalvinjj
    @KalvinjjАй бұрын

    I wonder how effective spark gaps are, given they're pretty much free to add to a PCB. Our TV's power supply got quite a few of those, and after a lighting strike nearby, the cable TV box burned and it made the favor of killing the TV's motherboard through HDMI, along with the Switch dock on that same TV. Replacing the motherboard made it work again, but after a while the power supply also went bad, and I could see on the mains pins a tiny welding like dot on the metal casing (clearly an arc mark), along with a missing spike on the spark gap PCB track. It was already more than 10 years old at this point and it still survived that lighting strike.

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Thanks for the feedback. Interesting story. I should put spark gaps on my to do list for videos.

  • @stevebabiak6997

    @stevebabiak6997

    Ай бұрын

    Spark gaps definitely have a role in protecting electronic circuits from discharges of energy. In the world of color CRT displays, it was very common to have spark gaps integrated into the CRT connector socket as part of the protection for the video output circuits. The socket would also use a thin but wide grounding “wire” (strap) that would typically get connected to the outside coating on the CRT funnel, to have a low impedance ground return for any arcing that bridged the spark gaps.

  • @coxsj
    @coxsjАй бұрын

    Interesting, educational and entertaining as always! Thanks for making and sharing!!!

  • @ErickBuildsStuff
    @ErickBuildsStuffАй бұрын

    I would like to add some observations and know more. I have seen many SMPS with MOV for protection. First failed component I always saw is MOV with dark discolored and often cracked like 2 separate disks for each terminal. It happened over a few years in India and often with power surges. Specifically they open circuit after 3-5 power surges. Which is around 2 months of time. I tried observing this because another SMPS had a fuse installed instead of MOV with almost same rating. These SMPS were used to power small LED panels for a business display sign with a LED driver always.

  • @SuperSerNiko97
    @SuperSerNiko9729 күн бұрын

    At 6:12 there is a mistake: increasing the air gap doesn't increase the voltage across the board but only the voltage across the air gap, doing this just increases resistance and reduces the current.

  • @lebasson
    @lebassonАй бұрын

    Love it, thanks for these practical helper videos

  • @hadibq
    @hadibqАй бұрын

    nice video greatscott. thanks for sharing.

  • @michaelkaliski7651
    @michaelkaliski7651Ай бұрын

    I have experienced two direct strikes on antennas fitted with lightning arresters and direct grounding wiring. The equipment survived without damage but proper protection is a bulky affair with thick cabling required to provide a low impedance path to ground. All the power circuit protection devices tripped, but no damage was done and everything worked after the tripped breakers were reset.

  • @kaumohlamonyane272
    @kaumohlamonyane272Ай бұрын

    Man, I've been a fan of yours long enough to know your real name. Haha, I think it's about 10 years that I have been a subscriber (when you still responded to messages on facebook within 24hrs, haha). I started watching you when I was in high school at 14 years old. Actually, you played a very big role in me studying BEng Electronic Engineering. I am now 24 working as an electronic engineer. I recently did an ADC protection design for one of our products where I used TVS diodes. I actually learnt what those are from you years ago. If I ever find myself in Germany, I'd really like to have lunch with you. I don't think you realise how much of an effect your videos have on some individuals. Much love from South Africa.

  • @zevakikel
    @zevakikelАй бұрын

    Good content! Thanks for sharing

  • @AJB2K3
    @AJB2K3Ай бұрын

    This turned up at the moment I needed it.

  • @CruzMonrreal
    @CruzMonrrealАй бұрын

    Ngl, this is the first time I've heard of a MOV, and the timing couldn't be more perfect!

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Glad to hear it👍

  • @boots7859

    @boots7859

    Ай бұрын

    FWIW, there are a lot of tutorials on how to add these to power strips, like one that your computer system is connected to. The better 'strips' have these, however seems to be pretty easy to add higher spec'd ones to your existing ones pretty cheaply. Wonder if there is a 'standard' which incorporates both the MOV and TSV in series to eke out most protection...

  • @Todestelzer

    @Todestelzer

    Ай бұрын

    I installed on every circuit with expensive Elektronik, a surge protector to my outlets. Inside they have a couple MOVs and one GDT.

  • @ANANTHASANKAR_UA
    @ANANTHASANKAR_UAАй бұрын

    Small Neon Bulb can also serves as surge & lightning protector and suitable for small outdoor antennas. Its break over voltage is about 90v

  • @unimportant5122
    @unimportant5122Ай бұрын

    As far as your microcontroller supply line goes, simply adding the 100n decoupling cap that should be there anyway will pretty much protect it against ESD. The pulse is high voltage but very low energy (standard ESD model often uses 150pF) and thus the decoupling cap will act as a capacitive divider and "eats" the ESD pulse.

  • @TheSomar1991
    @TheSomar1991Ай бұрын

    Very interesting and informative. thank you for the great videos keep it up

  • @CasualInventor
    @CasualInventorАй бұрын

    9:14 Why was the LED still blinking after you removed the protection and shocked the circuit again?

  • @aleksaggor
    @aleksaggorАй бұрын

    Amazing video, learned alot!

  • @rsdandy
    @rsdandyАй бұрын

    Fantastic video, thanks for sharing!

  • @M0UAW_IO83
    @M0UAW_IO83Ай бұрын

    I've seen real weird stuff happen with lightning strikes, I'm sure it could be explained but oddness like a garden patio covered in tiny copper balls which were the leftovers of the coax from a direct strike on a TV antenna but the TV itself worked just fine, pretty much every piece of electronics in the house next door was dead, there's just so much power that it's incredibly difficult to defend against. Static is easier but it's always good to know that MOVs, VDRs and transient suppression devices like those tiny diodes degrade every time they're 'triggered', it's a real common fault for them to fail on USB ports in handheld devices for instance

  • @Gooberslot
    @GooberslotАй бұрын

    Very interesting video. Definitely learned something.

  • @MCsCreations
    @MCsCreationsАй бұрын

    Awesome! Thanks a bunch for another lesson, dude! 😃 Stay safe there with your family! 🖖😊

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Thanks. You too :-)

  • @TheLooney1976
    @TheLooney1976Ай бұрын

    The main reason the MOV is protected by a fuse in series is not because the fuse will blow in the case of an overvoltage event. As the MOV starts to age due to surges, its resistance decreases, which in turn increases the current flow through the MOV, leading it to heat up and you end up in a vicious circle that will end in the MOV bursting or cathing fire and the circuit, without the fuse, drawing way more amps than anticipated. In order to protect that from happening, the MOVs are now protected by a fuse.

  • @BenM0
    @BenM0Ай бұрын

    Thanks for sharing a great video and topic

  • @TheRealWindlePoons
    @TheRealWindlePoonsАй бұрын

    We used to add MOVs to anything with an inductive load (PLC control systems working at 24VDC). Even contactors or solenoid valves can be a problem. Inductive spikes were a particular problem with high speed counters or servo-motors which use incremental encoders. An extra count here and there can really foul things up for the position of a pick and place robot.

  • @pjosephlthewonder5082
    @pjosephlthewonder5082Ай бұрын

    TVS packs are the electronics tinkers best friend!! In many years since I first used one I do not think any of my projects have ever been without one. Though I have moved in the last few months to a new location there are so many things they want me to do here. First was the safety light in the stairs and then the active emergency LED lights in various rooms that are going through a minor upgrade. But the use of the TVS ane other types of protection devices is common in this lab. Peace

  • @godfree2canada
    @godfree2canadaАй бұрын

    question. does the cheap SPD have an LED in series (leak current) with MOV? if so would it not work in reverse flow and not react fast enough?

  • @miltonthecat2240
    @miltonthecat2240Ай бұрын

    The GDT can create a lot of interference and scramble sensitive logic circuits digital logic since when the tube fires, the voltage across it collapses very quickly to a lower voltage, creating EMC surges. TVS diodes and MOVs tend to create much less EMC interference because they clamp the voltage and don't exhibit the voltage collapsing effect. So whenever we have to use a GDT (for example, when extremely low leakage current and stray capacitance is critical), we have to incorporate other protective devices in such a way to minimize the EMC surges.

  • @ingolister6414
    @ingolister6414Ай бұрын

    Thanks, sometimes I think you are looking over my shoulder with the timeliness of your videos. Right now, I was designing a circuit that needed this type of protection, and here you are with helpful advice.😀

  • @stevebabiak6997
    @stevebabiak6997Ай бұрын

    Fun fact: some CRT display video output amplifiers used neon bulbs to protect against the CRT arcing through the video output electronics. Quite like a GDT as shown in this video, but you could see them flash occasionally while in action.

  • @AndreasAn
    @AndreasAnАй бұрын

    Just woke up and learnt something about overvoltage protection. This will be a great day!

  • @muhammadawais7288
    @muhammadawais7288Ай бұрын

    What is the path of current in TVS in case of ESD. when circuit is not connected to anything. can u explain a little please. As in case of powered Circuit a transient in Supply voltage the current will be passed to GND but what is the case when circuit is not powered

  • @arduinomaster7334
    @arduinomaster7334Ай бұрын

    Nice informative video once again

  • @zaidhussain5206
    @zaidhussain5206Ай бұрын

    Hi Scott This video is really interested, I am about to built a PoE injector for my wireless point to point device , I wonder if I added the GDT over the data line is that will effect the data rate ? the connection speed of the data is 1Gbps , is that make work in less data rate ?

  • @mschwage
    @mschwageАй бұрын

    Very interesting. Thanks for an informative video. This isn't something you often think about when building a circuit.

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Glad you enjoyed it

  • @marcfruchtman9473
    @marcfruchtman9473Ай бұрын

    Great video!

  • @oalfodr
    @oalfodrАй бұрын

    If you ever saw or will see such an IC on a PCB then there is a big possibility that it is a transient voltage suppressor IC

  • @DanielsGameVault
    @DanielsGameVaultАй бұрын

    Spark gaps on PCBs are also commonly found in the primaries of power supplies for this purpose. Thought they deserve an honorable mention :))

  • @qaishusam
    @qaishusamАй бұрын

    Question is what pins/components need TVS protection? Does each signal on a PCB need protection?

  • @RaymondDay
    @RaymondDayАй бұрын

    Thank you. I have a Ethernet switch had on solar power and the 12 volt regulator went bad and it did about 24 volts then and 2 surface mounted components right by the power input blow up L2 and L3. From this video I order 2 SZSMF4L12AT3G Zen TVS 400W 12V UNI from mouser. I hope that fixes it. Looked up "12 volt TVS diode" I guess for 12 volts it should be 12 volts right or maybe a little more for leeway? Thank you.

  • @marian20012
    @marian20012Ай бұрын

    I have learned something new, never heard of HV protection and I am into electronics for more than 20 years.

  • @teardowndan5364
    @teardowndan5364Ай бұрын

    Increasing the gap voltage doesn't change the voltage applied to the board by much since most of the extra voltage simply gets lost in the arc. It does increase the peak discharge current though. As for why the MOV manages to save the circuit despite having much higher voltage, that is down to your generator having pFs of output capacitance discharging into the MOV's nF of parasitic capacitance, forming a capacitive voltage divider that drags the discharge voltage low enough to save the input pin from excess ESD current. Also, IO pins have their own internal protection from the output FETs' body diodes that can usually handle human-body-model ESD as-is as long as the chip has a path from power+ground pins (depending on ESD polarity) to actual ground. Chips on an assembled grounded PCB can be surprisingly difficult to kill as Linus demonstrated in his Electroboom special.

  • @SuperSerNiko97

    @SuperSerNiko97

    29 күн бұрын

    I think you are the only one in this comment section who actually knows stuff.

  • @wyrdlg
    @wyrdlgАй бұрын

    That was Great, Scott!

  • @jasonkocher3513
    @jasonkocher3513Ай бұрын

    Thank you for the deep-dive and clarifying these parts. What is the best practice for TVS application in a digital circuit? Just on the power rails? Power rails and any connections that touch the outside of the product housing? What about cap touch LCDs that get touched (obviously) - their power rail too?

  • @Prashant5479
    @Prashant5479Ай бұрын

    Awesome!!! Thank you!

  • @greatscottlab

    @greatscottlab

    Ай бұрын

    Glad you liked it😁

  • @user-ng2dl4eg9y
    @user-ng2dl4eg9yАй бұрын

    Hey GreatScott!! I would love to see a video about ferraite cores.. how do they work and when/how to use them 😊 i think its a quite intersting topic

  • @thedarksage328
    @thedarksage328Ай бұрын

    Great info!

  • @arp_catchall
    @arp_catchallАй бұрын

    Thanks for the video. What would be equivalent protection chip for 3.3V? Many of us are switching to ESP32.

  • @jeffschroeder4805
    @jeffschroeder480515 күн бұрын

    I used some components like the GDT to protect a lora antenna coax from high transient voltages, probably will not know if it really works until it doesn't. I think it was suggested to replace them occasionally as repeated spikes can make them fail. I imagine that a passing thunderstorm could induce significant spikes even without a lightning strike. I really appreciate the information you provide, Thank you.

  • @crow4865
    @crow4865Ай бұрын

    About 10 years ago I accidentally connected a 12v dc circuit to 240v ac, when it didn't work I soon realised my mistake and connected it back to the proper 12v dc again and it worked. I've never quite understood how the 240v didn't fry it. that same board is still working to this day.

  • @styrishrodrigues
    @styrishrodriguesАй бұрын

    9:52 i thought - Gate Drive Transformer

  • @vthrash7832
    @vthrash7832Ай бұрын

    I dicovered TVS and varistors while reasearching for a DIY TIG welder, they seem to be used at the output of the Diode rectifier to avoid the HF/HV starter from blowing the diodes

  • @Graham_Wideman
    @Graham_WidemanАй бұрын

    It probably should be mentioned that MOVs have a limited number of "hits" they can take. Or to put it another way, they get less effective each time they are activated. It would be very informative and intuition-building to see you demonstrate that effect!

  • @bob_mosavo
    @bob_mosavoАй бұрын

    Thanks 👍

  • @Elijah-2000
    @Elijah-2000Ай бұрын

    Thank you for this informative video. Hopefully it solves my home made MPT Solar Controller which has failed twice now, due to local lightning strike ⚡

  • @187tomate
    @187tomateАй бұрын

    but aren't the most uC already esd protected? Or what do these ESD-values in the data sheet mean?

  • @ZugTheDragon
    @ZugTheDragonАй бұрын

    Very nice video! One overvoltage protection circuit (not sure if it'd be a surge protection then?) that I found interesting is the crowbar circuit. I saw it first on the output side of a 3.3V PSU, but don't know too much about their effectiveness, are those too slow to act as surge protection?

  • @mikek1187
    @mikek1187Ай бұрын

    It would be interesting to see you build some "crowbar" circuits for smaller electronics so we could see how they also work in protecting electronics.

  • @stm32user
    @stm32userАй бұрын

    GDT is used in telecom wire communications mostly great scott

  • @traisjames2
    @traisjames2Ай бұрын

    What are you using for the blinker IC? Just a 555?

  • @user-gj9md6hr6g
    @user-gj9md6hr6gАй бұрын

    I learned something new through your video

  • @mikesocha1734
    @mikesocha1734Ай бұрын

    Won't the shunt capacitnce from the varistor across the supply rail reduce the peak surge from the spark? On a supply rail you can add capacitnce which in conjunction with the short time of the fake static distarge would provide enougbh protection.

  • @scr1ptery642
    @scr1ptery642Ай бұрын

    Nice video 😎 Off topic: you make new coilgun with capacitors and igbt/scr ? 🙃

  • @mobabot
    @mobabotАй бұрын

    what printer do you use and how many pages do you print a month??

  • @DanAndersen_
    @DanAndersen_Ай бұрын

    Thank you @greatscottlab This video was very educational. What book would you recommend getting similar information for electronic tinkerers? I typically find very theoretical books on electronics or super simple books which mostly around: how to tinker with arduino with components. I saw a video from Adrian Black once, where he exchanged elcos agains ceramic caps and worked with a conversion table. I really would like all these practical helps in a single source like a book or similar.

  • @kondzio2003
    @kondzio2003Ай бұрын

    Great video

  • @KeritechElectronics
    @KeritechElectronicsАй бұрын

    "One point twenty one jigga-watts! Great Scott!" Definitely interesting; I'll use TVS diodes in my projects more. MOVs are pretty common, I replaced a good bunch of these in various devices, which means they did a good job of protecting the circuit.

  • @paulmeynell8866
    @paulmeynell8866Ай бұрын

    Excellent video , could you put all 3 in parallel? That would give speed and high energy?

  • @jeffspaulding9834
    @jeffspaulding9834Ай бұрын

    GreatScott: While such events are rare, they can immediately destroy your electronics... which we definitely want to avoid. Electroboom: Say what now?

  • @yacineyaker7485
    @yacineyaker7485Ай бұрын

    i designed a board based on stm32 it was working fine until it started to draw a lot of current even tho my dc/dc converter wasn't destroyed but the stm32 is heating like crazy. idk why this happened any ideas?

  • @Benjaminfenk
    @BenjaminfenkАй бұрын

    What would happen if a TVS is connected in reverse polarity with the same standard voltage?

  • @SlykeThePhoxenix
    @SlykeThePhoxenixАй бұрын

    What is the generator at 2:15 called and where can I buy one?

  • @davidjackson2115
    @davidjackson2115Ай бұрын

    Thanks. The amount of boards that blow.... and now i know what those funny things are - i thought they were caps but didnt behave like caps.

  • @helmutzollner5496
    @helmutzollner5496Ай бұрын

    Hi Great Scott! Very interesting program. Great that you opened the two overprotection circuits. Interesting to see what they are doing to protect from the surge. HOWEVER, the really interesting teardown would be the OBO Bettermann Surge Protector. I have been wondering for many years what is the magic in there and why they are pretty much the only source for this class of surge protector and what they use in there to justify such a steep price. Last time I looked at them some 20 years ago they were over 300 € each. So, if your budget for a program stretches tgatbfar could you examine the OBO device. BTW the OBO device is the one that is use by pretty much all the railways around the world for serious surge protection. So, what is their magic sauce?

  • @DiederickABecker
    @DiederickABeckerАй бұрын

    Is there a video of you making the HV generator?

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