Aw shucks, thanks for the mention. I like to leave the mistakes in my videos and openly discuss them because it reassures people that they're not the only ones who make mistakes.

Great to see you back making videos Jeri, and thanks for the shoutout!

"Bad systems are designed to work properly Good systems are designed to go wrong properly." - Keep up the good work Jeri.

Ah, the paper clip test! Many years ago I was a video engineer in the BBC studio shooting an episode of Dr Who (Tom Baker!). Our cameras were EMI 2001s which had 4 pickup tubes which had a 525V DC supply fed down the camera cable. There were 4 seperate supplies, one for each tube. About 20 minutes into the recording session in the middle of a tack, one camera suddenly lost one of the colours and then went off. I went to check the power supply in the rack, and sure enough it had tripped it's breaker. To cut a long story short, I went onto the studio floor while a colleague Eric stayed in the equipment room. I unplugged the camera from the wall socket, and plugged it into a different socket while Eric changed the PSU. We blew the breaker on the spare! I looked at the cable and found that it had arced over. This was a 101 way cable! We changed the cable put everything back to the way it started and reset breakers. Again the PSU breaker tripped. We found that both wall sockets had arced over. After changing the camera head, the cables and using a new wall socket we had things working. When the recording session was finished I went and got the camera head moved up to the studio workshop so we could check it out. The problem was that a production person had put a script on top of the camera, and when they took it off the paperclip had come off, fallen into a ventilation slot and shorted out one of the 525V supplies! It took me the best part of a day to change out components in the camera head that had been blown. Eric had a much easier time with the PSUs as only some fuses had been blown. The cable ends and wall sockets were a much bigger problem as they were all potted and had to be broken open. It took a couple of wiremen several days to replace the wall sockets and the cables got sent back to the manufacturer. Those were the days! Just for the record in the early 70s a single EMI 2001 camera system (camera head, PSU, Control Unit and monitoring) cost the best part of £100K! About $200K. We had 5 plus a spare, not to mention the video and audio control and distribution kit plus about 4MW of lighting. At the time I owned a 3 bed house which had cost me £4,250. How times have changed. Where I live in SW London, a 3 bed house would cost at least £400K, and I could by a good Pro-sumer 4K video camera with lots of bells and whistles for £5K. At the time I took all the studio gear I was working with for granted. Great video Jeri. Nice to see you back.

We don't care if you messed up. All we care about is that you are back on KZfaq.

I am so glad you are back posting videos Jeri !

It makes me really happy to see that you're posting again Jeri. I've always enjoyed your videos for your strong and unique character as well as the insightful curiosity of your content. Welcome back and thank you.

I just got finished listening to your story, (restarting the video),for the second time. I'm amazed by all you have gone through. Your an amazing woman!

Jeri, I first saw your Commodore based bass years ago and only recently dedicated the time to research your accomplishments and watch some of your video. I hope It's not too far to tell you that you are brilliant. You are the type of strong leader that current generations desperately need. I wish you the very best in life and I hope I get the opportunity to show my son new videos of yours, someday.

Thanks for coming back! So happy you're making videos again. Your channel was making me so sad, because all your old videos were super cool. But seeing a bunch of new videos in the last few weeks, it's really a great surprise!

Very happy to see you producing videos again! Your topics always teach me something! Although I don’t always understand everything, I deeply appreciate the pure genius behind it! Keep up the great work! 73 de Seth - W8FG

Jeri, you're a real inspiration to people. We all make mistakes, don't worry about it. You can even just edit the videos into something that is "perfect". You don't have to get it all perfect in one take, just do what makes you happy :)

Your content is calming to watch. Which is nice when I’m trying to learn something and I get confused. Thank you 🙏

Why have I not come across your channel before? That was a beautifully presented summary of low power reverse polarity protection options! Definitely gonna look at more of your content... Thank you!

Hello Jeri. I came across this clip while searching for OC protection on my breadboard+PSU combo unit. I have now started watching some of your 2009 clips, very retro for me. Thanks for the calm and precise delivery. Best regards Mark (UK)

Jeri! I am so glad you are making videos again. This stuff is GOLD. Keep it up!

I really enjoyed this video. (I have some knowledge of electronics and almost zero hands on circuit building) Your video breaks down your project in a way I understand which inspires me to dig the breadboard out and visit the world of circuit construction again. I also like how you provide links to other cool videos of what other thunder nerds are up to. Thanks!!

When I read the title of the video I immediately thought about Big Clive. His teardown and reverse engineering videos are golden.

I’m so happy to see more uploads from you, my sister and I need more role models like yourself. :)

Jeri, great video and design using the PMOS diode(s). Thanks for sharing and welcome back!

I really enjoy these videos! They’re also a great public service! Electronics for me is a hobby and these videos have really educated me and have been super entertaining. It’s also great that Jeri has been self taught and can present things in a way a self taught student can understand.

I'm so glad that she is back, always thought her videos where among the most informative electronics videos on KZfaq

I am delighted you are back posting again Jeri. I have really enjoyed all your videos. You bring an interesting perspective to our amazing hobby by thinking outside the box too. 73 from MI6GNP and Merry Christmas from Northern Ireland with best wishes for a great 2019.

I can't describe how much I like your videos. Thank you :)

So glad ur back on puting videos on youtube. I love listening to the interviews you give about your life and story such a cool story sure ur saying yeah it hasent been all cool :)

Jeri, I love what you do. Your way of understanding and explaining electronics is just brilliant. I guess that's because you figured most of this out by yourself, as opposed to "being taught". I hope you will inspire lots of girls and boys to play around with electronics - not as a career, but as a way of life. As a father of three girls I know how badly we need inspiring personalities like you.

Great video, I'm glad I've found your channel. Incidentally I once worked with someone who showed me that the protection circuit could be built "the other way up" using an n channel device. The advantage of this was the slightly better performance of the FET. The problem is of course that the positive rail runs from battery to load and the FET is in the negative rail, so battery negative isn't at ground. This really only matters if the battery negative is run outside the equipment for anything other than an isolated charger. Incidentally I'm now usually the embedded software geezer and I DON'T leave loose change on the bench. :=*)

You have to be my soul mate. After watching your interview im blown away. Your so smart it makes my heart flutter. I could listen to you all day. Earlier today i came across your video for making an x ray scanner with mouse. Helped me figure out what 5g is. So thank you for that. Its a giant xray grid. Probably the all seeing eye, but you made my day even after that.

I love it when KZfaq actually suggests a video I enjoy. You rock. New subscriber earned!

Even though Big Clive and Dave do teardowns, there's a serious difference in how valuable the things they tear down are. Big Clive : I got this novelty light from Poundland for £1 and I'm tearing it down EEVBlog : My neighbours threw away another $100,000 workstation. I'll tear it down, replace a few capacitors and get it working.

Love that You are back on YT

Nice Video Jeri! Can't wait to see what other gems you have to offer... i see a backlog binge session in my near future.

We all make mistakes. I believe it even was you who told us in an old video that "to learn and succeed you need to make *Lots* of mistakes". And tbh you just showed me protections that are in devices all around me, in clear human-speak even.

Merry Christmas and Happy New Year 2019 to you! Thanks for your videos!

I really love the old content you put out there :)

I'm so happy to see that you're back.

Nice video Jerry. Happy to see you again ! I love the calm way you explain and in contrary to the other videos you keep it to the point and short. Hope to see more videos of yours.

Nice! I have also used a single n channel mosfet in the negative input leg. N channel mosfets generally have a lower on resistance than p channel. I had never thought of your circuit for current limiting also. Thanks for that additional insight!

We love your way of teaching each and every bit of detail in depth , thanks mam for reunite with us ur comeback means a lot for me 😊😊😃

Hey Jeri, Thanks heaps for sharing! Using the PMOS transistor in the linear region for current limiting is an application I'll have to keep in mind next time I need some cheap and cheerful protection from... less than carefully chosen peripherals.

I missed you so much, welcome back.

My new favorite lady! Subbed! Where have you been all my life? Your vids are helping me refresh my memory on electronics. You can't fire yourself...ever!

You have a Robie! I had one when I was a kid. I took him apart and springs and gears went flying everywhere. I was sweating bullets for over an hour trying to get him put back together. But I eventually got him back to working. And I learned a lot about mechanical things. Fun!

Great to see you again! Great video as always

Thanks for producing great videos. 👍

Thank you. I worked as a chemist. I was able to survive my mistakes and those of others. Great video.

I've heard the 'Explody diode' called a crowbar circuit before. I've used that with a PTC fuse with good results. A P-channel FET is easier in some cases, though. I do a lot of work on high-end programmable LED hula hoops, which have some interesting design constraints. Everything has to be small and tolerant of board flex, but for practical reasons (like being able to assemble boards on our little in-house pick and place machine and to be able to repair things by hand) component count ends up often being a bigger concern than cost.

This is really good for me, I'm doing a Ben Eater 6502 build, and the other day I tied power to both VCC and VSS on the processor. I was sure I'd cooked it. I hadn't, but circuit suggestions like these could save me some sweat and tears, down the road, particularly the reverse polarity part.

This was really useful, and a joy to watch.

Im glad you are back !

Thanks a lot for sharing tricks of the trade. It's very interesting to learn about the pros/cons in the engineering process.

I wondered where that went! Thanks for fixing it and thanks for being Jeri!

Jeri, Just loved the video. Such a common problem. Must admit I need to catch up with modern techniques. Will be watching this a few times, as it takes a while for my one remaining grey cell to absorb things. Thank you so very much. Oh! and such a cool ammeter! Some of us remember when they were modern.

A collab video between you and ElectricBOOM has to be one of the greatest thing happening on KZfaq.. 💪 #Rectifier!

Thank you very much for this explanation and discussion! It gives me a head start on my circuit.

Thanks for coming back 😀😀😀

Very basic and useful circuit, keep them coming!

You are amazing. Thank you for this break down. You are a wonderful teacher.

Hello. "Explody diode" at 3:44 is well-known protection method however "PMOS diode protection" at 12:00 is new and good method that you disclose. Thanks for your good explanation on the video.

Love the idea of 'Nerd Thunder' ! Thanks...

Hi Jeri, thanks for all your work!! Just trying to learn something about AR/VR glasses! Will check all your videos and make loads of questions!!

The reverse diode across the supply with a fuse is the DC version of the "crowbar protection circuit" replacing the SCR with a diode.

N-channel, p-channel, who cares. The best channel is the Jeri-channel.

This video is proof why everybody is so glad you are back!!! So are you telling us to go to big Clive to see the exploding diode? Lastly, are you telling us this is not a perfect world so design as such? Great video - keep it up!!!

It would be amazing to start seeing you posting videos more often! I'd love to share them through Tefen's Tech to others in the PC Modding Industry.

Hey! You are back on KZfaq. I'm glad, you are really inspirational. Shame that I didn't get any notifications. I am positive that I was subscribed but KZfaq tells me I wasn't (I think KZfaq is lying to me) Subscribed again. And hoping for more great videos.

Jeri you spoil us!

Thanks Jeri .Your videos are EASY to understand.I was a Part-time Engineer at K-40 Electronics.I was one of the 7 Engineers.I was not that bright but,seeing my neighbor's Lamborghini(the older C.H.I.P.S. radar),with my product in it made me call my old Boss,at K-40 .Being Autistic is a challenge(as well as the Parkinson's) but,I LOVED electronics. Here's a KOOL note ;; The 1st girl that I,ever,kissed listens to my Global Station,1000 Miles from my the Studio(Panbeara-KFUY)!!! One of these day,I'll be able to afford a Kenwood,like the one on your bench.Thanks again for your videos. This is KE0DNQ.......73

Hi, nice video! "Final circuit": I've done this many times, but always put the reverse polarity first, complete with a 2 way tranzorb and used a PTC for "Shunt" that I call "Sense" for a better fold-back function. This type of circuit is very helpful for fault condition coverage of circuits that go into hazardous environments.

Jeri, darling, every one makes mistakes. You admitted yours and corrected it. Thanks, for the video and the honesty.

I'm just glad you are back, making mistakes is human

Very good video! Thank you. I like to see a well made discrete design instead of picking a fancy chip to solve all problems whithout knowing what's going on in detail. Please more....

As mentioned earlier, some neat overvoltage protection would be interesting. I suppose you have some great insight. Thanks for your awesome content, and glad to see you back here!

Nice circuit Jeri. Well familiar with the exploding diode method. My truck driver brother used to bring me regular examples of it to repair.

Many thanks for this info, I have learnt a lot. You have more than earned my subscription.

Another awesome lesson. Thank you jeri.

Hope to QSO someday. You, Leo, Joe Walsh, etc. You're in my top list of cards to get! Take care!

I am now caught in the nerd thunder tornado. And pretty happy about that.

Very cool video! I'm taking electronics in the spring and I can't wait to start understanding how to engineer a circuit, rather than only analyzing them.

This was the first I'd seen of you Jeri. In watching others too I'm like, wow this girl has some serious equipment, is this for real? .... After google, i see, of course, makes sense. Protection circuits will be NB for those mass market games! Luck! And thanks for sharing.

How am I only NOW discovering a) this channel, and b) nerd thunder?

Keep up this good work, great videos!

Haha, the SW-engineer situation is so spot on. A few months ago I was assigned to build a cubernetis demo cluster. Within the hour of the hardware arriving; Delivery packet wasn't assigned in my name unfortuanately so my lovely fellow SW- colleagues had put all of the 10+ rpi's in a pile (yes, like a big mikado-styled heap! Cables, PCBs flash drives and routers all laying ontop of another)... And ofcourse they powered them up and tried to setup the server... I was dumbfounded, these are after all MSc CS people... Pie's arn't that fancy nor expensive, but it was so unnecessary and leadtime can't be replaced.

You are a very special person A lot of positive energy

Hey Jeri. Loving this "relaunch" or whatever it is!

Nicely explained. Great drawings

I love your current limiting pull up design. I’ve got it burned in to my head after rewinding the video 10 times.

Wow; "Thank You", thank you very much for your presentation 😎

I’ve used almost that circuit in automotive engine controllers. The difference is that I arrange the low side resistor and voltage clamp so if the engine controller is in standby, the circuit is shut off, reducing quiescent current. In this mode the body diode supplies power to just the voltage regulator and it has OVP via a 8A27 TVS. The battery voltage usually makes the gate zener conduct. Because of this, I had to split the voltage limiter. It supplies a limited to 35V gated power feed to all other circuits, the OV clamp is powered between the two MOSFETs, and the gates are connected together so they share one zener, and the pull down and OVP have a single N mosfet with Vdd going to the gate. The junction of the two MOSFETs have the TVS that clamps at 45V (with about 100A load dump) to ground and that feeds the voltage regulator with a standby mode. I use a 20P06L FET, it can handle most load dump surges (verify with testing). The other MOSFET with a voltage limiter clamps to 35 volts and feeds the H bridges and other circuits that blow up over 40 volts, and turns off after the ECM goes to sleep, further reducing quiescent current. Only one more part needed from your component count, one small signal 60V logic level MOSFET. Note that to deal with reverse spikes, the gate pull down impedance needs to be low enough to discharge the gate in a couple microseconds so maybe 5-10k or so which is a fairly high load. Does that all make sense? With a battery, gating the pull down can save battery life. In my case, it’s battery life of a 60Ah, 12V lead acid battery, but at a parking lot for an extended couple month vacation. Those mAh add up. BTW plugging into an automotive 12V (or 24V) power supply bus is plugging in to a world from hell. Love your channel!

I always add polarity protection into my designs if there is a chance that a user will connect polarity incorrectly, but I usually don't bother with resetting current protection. My thought is that if overcurrent occurs, it's almost certainly due to a downstream fault, and therefore a resetting current limit doesn't save the product from needing repair. The original fault will still exist. So I generally fit fuses that are designed to blow to prevent the fault progressing to a fire or serious damage occurring. The exception to this is if there are external ports, e.g. USB ports. In which case, for those, I generally use current-limited load switches. But the DC input is still only protected by a fuse.

To make mistakes is human, and sometimes that's how discoveries are sometimes made.

I definitely use this circuit in my future projects thanks for sharing

Sorry to say, that was a way better demonstration than DJ or BC due to all the measurements taken. Keep up the good work.

Excellent circuit to protect against end user mistakes ....now, can you figure out how to keep the purchasing dept. from buying the cheapest components in their mis-guided efforts to save pennies while disregarding life endangering risk ? Retorical question ...this is a question without an answer. Glad you came back to youtube ...and that you're in sync with the best; Big Clive and EEblog.

I have dropped a scope probe onto a circuit, and shorted it to destruction. HDMI cables are excellent for this too. I have never placed a PCB onto loose change on the desk. I have to try it! Thanks for the suggestion.

Just discovered your channel.. Love your presentation style. Great video.

Very nice video, interesting to the end, thank you for uploading, i look forward to viewing more videos as they are produced. :-)

Nice protection circuit Jeri very useful. 👍

Couldnt wait for your new video!

I would tell you "don't be so hard on yourself", but I would need to learn to do exactly the same thing. Thx for the excellent video! I haven't watched the one with the flaw, btw :D