This $0. 70 Component SAVES your Circuit! EB#59
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Date: 2024-04-22
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Comments and reviews: 20
axelBr1
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.
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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.
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hanslepoeter5167
MOV or TVS diode are not that different. MOV is a sintered material and has the same diodes but just an enormous amount of them in parallel and in series. If these are protecting they can degrade bit by bit until they short or break. The TVS diode will be gone in one single overload. The GDT's are typically used to protect against lightning and always combined with THS or MOV. ( Which is the reason it failed to protect your controller )
In old TV's there was a component which just provided a spark gap in air. just 2 wires 0, 3 mm apart, serving as a GDT with the gas being air.
Worth being mentioned is clipping diodes in a digital input circuit. Often integrated in the IC but if not, it can be placed externally.
If lightning strikes directly, you can have all the protection possible: Nothing will save your circuit.
reply
MOV or TVS diode are not that different. MOV is a sintered material and has the same diodes but just an enormous amount of them in parallel and in series. If these are protecting they can degrade bit by bit until they short or break. The TVS diode will be gone in one single overload. The GDT's are typically used to protect against lightning and always combined with THS or MOV. ( Which is the reason it failed to protect your controller )
In old TV's there was a component which just provided a spark gap in air. just 2 wires 0, 3 mm apart, serving as a GDT with the gas being air.
Worth being mentioned is clipping diodes in a digital input circuit. Often integrated in the IC but if not, it can be placed externally.
If lightning strikes directly, you can have all the protection possible: Nothing will save your circuit.
reply
helmutzollner5496
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
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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
reply
moeburn
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.
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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.
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SkyhawkSteve
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.
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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.
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Kalvinjj
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.
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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.
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rdyer8764
I've used MOVs before, but didn't know about TVSs. Thanks.
I was wondering about your estimation of generator voltages. When I did experiments with other static generators, we estimated our gap voltages at 10kV/cm. 4 inches was 100kV. I'm not sure which is more accurate, yours or ours. Of course we were in a fairly dry climate.
Also, did you notice a change in spark frequency when you increased the distance (voltage) It seems to me that it should take longer to to build enough charge to jump a larger gap, implying that the frequency should go down. Did you notice that phenomenon
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I've used MOVs before, but didn't know about TVSs. Thanks.
I was wondering about your estimation of generator voltages. When I did experiments with other static generators, we estimated our gap voltages at 10kV/cm. 4 inches was 100kV. I'm not sure which is more accurate, yours or ours. Of course we were in a fairly dry climate.
Also, did you notice a change in spark frequency when you increased the distance (voltage) It seems to me that it should take longer to to build enough charge to jump a larger gap, implying that the frequency should go down. Did you notice that phenomenon
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ErickBuildsStuff
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.
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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.
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Alacritous
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.
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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.
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R. Daneel
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.
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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.
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DanAndersen_
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.
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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.
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greatscott
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
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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
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Graham_Wideman
GreatScott -- I don't know how deep on this topic you're interested in going, but -- in light of your summary at 10: 31, it would be interesting to explore how to use these components in combinations. (Along with spark gap which is essentially DIY GDT) It might seem using these in some combination might handle multiple over-voltage/arc scenarios, but does the right protector step in at the right time or voltage to avoid the other protector getting overstressed
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GreatScott -- I don't know how deep on this topic you're interested in going, but -- in light of your summary at 10: 31, it would be interesting to explore how to use these components in combinations. (Along with spark gap which is essentially DIY GDT) It might seem using these in some combination might handle multiple over-voltage/arc scenarios, but does the right protector step in at the right time or voltage to avoid the other protector getting overstressed
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andymouse
How about this for a series ' Re Visit Re Vamp' where you go back in time to an old project do it differently and better eh sounds awesome yes your very exited right I have a selfish reason! I could never get get the hard drive as a rotary encoder sensitive enough to be of any use in MAME despite playing around with opamp's Schmitt shaping and other stuff. However the idea for the show is not the worst idea I've ever had. but very close. cheers!
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How about this for a series ' Re Visit Re Vamp' where you go back in time to an old project do it differently and better eh sounds awesome yes your very exited right I have a selfish reason! I could never get get the hard drive as a rotary encoder sensitive enough to be of any use in MAME despite playing around with opamp's Schmitt shaping and other stuff. However the idea for the show is not the worst idea I've ever had. but very close. cheers!
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Dwonis
I wish Mouser wouldn't staple and/or tape individual component bags.
I ordered some connectors from them in Canada when their competitor didn't have the what I needed, and was immediately irritated by their packaging.
I was also disappointed with the granularity of their online component search, but I don't know if that's a general problem or just with the specialty connectors I was buying (M. 2 sockets.
Good video, though. Thanks!
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I wish Mouser wouldn't staple and/or tape individual component bags.
I ordered some connectors from them in Canada when their competitor didn't have the what I needed, and was immediately irritated by their packaging.
I was also disappointed with the granularity of their online component search, but I don't know if that's a general problem or just with the specialty connectors I was buying (M. 2 sockets.
Good video, though. Thanks!
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dr. robertnick9599
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
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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
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Ajax4Hire
Yes, ESD and Surge protection does NOTHING(and it is suppose to.
Like a Seat Belt, helmet, bullet-proof vest; you do not need it right up to the moment you do.
Then you are either glad that the extra cost was added to the design. or not.
Beware, ESD and Surge protection can be removed for cost saving in production and no one is the wiser till boom.
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Yes, ESD and Surge protection does NOTHING(and it is suppose to.
Like a Seat Belt, helmet, bullet-proof vest; you do not need it right up to the moment you do.
Then you are either glad that the extra cost was added to the design. or not.
Beware, ESD and Surge protection can be removed for cost saving in production and no one is the wiser till boom.
reply
PhilipKloppers
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.
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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.
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unimportant5122
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.
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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.
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demetrisswest
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
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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
reply
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