I feel ... included! :D

That power supply has the weirdest heatsink I've ever seen and I love it

If Tesla hired Electroboom... *car exploded* "NO REVERSE POLARITY PROTECTION, WHO DESIGN THIS SH*T?!"

remember kids, don't drink and charge

is it just me or is that the coolest looking heatsink? (1:33)

Scott always impresses me with his soldering skills. Amazing as always.

Very good scott ! I recalled 10 years ago when I taught industrial technicians/engineers ElectroPneumatics .The new laymen/greenHorn always causing 24v 10A power supply burnt. When I open out the CE or Industrial Professional power supply : The fast blown fuse never burn but others components burnt. Later I change the Fastest-fuse.Yet the same history happening .The last resort are buying two diodes lm4002. Same situation occuring.Finally I had to use lm4007 diodes, each connected inseries with + terminal and -terminal respectively. Good luck ,for more than ten years nothing Power Supply will ever burnt occuring !

Finally. We'll be able to see what's inside after so many long years and countless videos in attendance.

Inspite your explanation, I would still go for the reversed diode but added with a (reachable!) fuse. As in a good PSU design, the sensewires should be connected as close as possible to the load. The fuse can be quite overdimensioned compared to the PSU maximum current as the PSU has its own short circuit protection.

You might throw in a warning to test this out with a lower current battery rather than a high current SLA battery. A 12V SLA battery can easily dump enough current to fry decent sized wires and start fires. Don't ask me how I know. Always use a fuse with such batteries.

At first was thinking same video as many before but after watching you came to problem well known to me and as well finally someone who made video complete by showing right circuit at the end which will protect power supply on right way.

Your videos got me into this kinda thing and ended up convincing me to get a career in electrical engineering. Thank you

I see it was an easy repair this time, but I would love to see you reverse engineer things and general repair tips and tricks. Maybe this isn't your cup of tea, but if it is, it'd be very interesting. I got into electronics largely because I like transforming what other people see as waste, into useful resources again. I've spent many hundred hours in my garbage room, salvaging parts, working electronic gadgets and also repairing and giving away or selling cheap. Through your channel, I started building things from scratch, but I would also like to develop my repairing skills. So I'd love to see more of you, repairing things and describing the most common causes of modern electronic devices failing :)

This is one of the best channels on UKposts and because I watch this channel my electronics ability has soared. Thx

Just made the same mistake and blew my small 30V DC-DC module. I will try this Reverse Voltage Protection method. Many thanks!

The same happened to my power supply, I wanted to charge a RC car race pack with 7.2 volts and the output of the supply was shorted. You and Electoboom helped me to repair it. The revers protection circuit in a labory power supply is like this, because it dont has any effect on the current and voltage output and vorsmall loads (inductive spikes, capacitors) this version is perfect. Its not made to protect against big current and voltages.

The best reverse polarity safety is a full wave rectifier.

I guess this topic belongs to #electroboom 😀

I began watching you clueless to the technical side. Now with you and some other instruction I am beginning to grasp this

With this added information I’ll be making my own bench top power supply. Great video, thanks.

Doesn't the cut-in voltage of the MOSFET limit the minimum voltage you can output from the power supply? It would seem to me that a virtual zener that drives a N channel MOSFET, via a proper driver chip, would be another solution with fewer drawbacks. N-channel MOSFETs tend to have a lower resistance too.

Wow. Very nice to see a new GreatScott video on Friday ^^ I actually destroied a power supply at work also by connecting a big 12V Lead acid battery the wrong way around. Should have used this circuit ^^ Thanks for the advice!

Really great vid to show the 'flaw' of the design of your power supply including a fix!

hey that's such a coincidence. I did the same a week ago and now am able to repair mine as well, thanks a lot

You mentioned electroboom finally 😍

There are circuits that use a relay in line with the load. The coil is driven by a circuit that detects very low reverse voltage and opens the relay.

I have to respect someone who makes such clean schematics. Subscribed.

GREAT video! It was a little tricky to understand why fuse kept blowing & mosfet kept conducting currents when reverse-battery-voltage was applied, but all in all, great!

I don't know if its just me, but the whole video from start to finish seemed like it was running 10% faster then normal. Awesome video and thanks again for sharing your knowledge.

7:45 This isn't a new design. I've seen this circuit 15+ years ago. Depending on how you design it, it can also double a basic step down regulator.

Thank you for posting such an instructive and practical video on reverse voltage protection circuits !

Hvala Vam puno na korisnim savetima na vašem kanalu. Thank you very much for the helpful tips on your channel.

And that's what "ideal diodes" are made of.

No power supplies were harmed during the making of this video

Haha, been there - none it (blowing up my power supply). But you do have to love the power mosfet versions ! Just build it into your power supply and change the point where your power supply monitors the output voltage to the output of the mosfet protection circuit.

Thank you for your time and effort to produce these excellent videos! You appear well versed in MOSFET selection. I have a reverse voltage polarity 6 - 8 VDC, 15 AMP (max) application I am evaluating that will require a low side N-Channel MOSFET. Any initial suggestions?

What kind of power supply is it? What is the Max Voltage,Current and power.

Make a tube amplifier

Thanks for video We can use a relay with a diode to protect from wrong polarity without voltage drop But must use same voltage for relay coil and for the load

Great tutorial You can use a thyristor with a relay When a reverse voltage detected by thyrisyor it triggers the relay and opens its switch note to use a Fast acting relay .

the circuit you found is a poor solution because after it is used once you have to remove the gate charge as the fet will stay conducting and when you try to hook a battery backwards it will be a short for a moment until the gate capacitance is discharged and the current can well exceed the maximum allowed by the fet. This generally will not fail right away but it does as I've built this exact circuit years ago for a charger we use at work and they fail about every 6 to 8 months. After an exhaustive look into the failure mechanism this is what I found. I measured sharp spikes in the 1000's amps using an irl60b216 once conducting and hooked up in reverse to a car battery

What if I add a FULL BRIDGE REKTIFIYAA.......?

Great video! I will have to add this to the power supply I plan to build.

Most interesting subject! Thanks for sharing and keep up your great work!

"It is bastards" - 0:38 (Enable automatic subtitles)

This is probably why using a lab power supply to charge a battery is not recommended. Battery charging circuits have protections built in for this reason.

Intro was one of my favorite

Thank you for this vídeo Scott

I prefer sticking with the original method to get accurate voltage also mistakes happen once I don't think I will blow the diode again in the future 🙂

Make a tube amp please! I know it is easier with solid state stuff but transistors will never beat the warm sound of tubes!

Thanks for sharing😀👍 Interesting project A good solution for a common problem👍😀

THANKS!!! I been needing this kinda info!

this system wouldnt be as bad if the diode could be swapped more easily

Best way for Reverse Voltage protection is DO NOT MESS WITH ELECTRONICS WHILE YOU R DRUNKED...!!! ;P ●●●●●●●●●●●●●●●●●●●●●●●

you could put a latching relay and diode to have close to no voltage loss and still a fiarly fast decoupling on reverse voltages

I've been working on a guitar effects pedal project and it needs reverse protection polarity. Some designs I've seen use the parallel diode setup like in your power supply but I've read a series diode is better. Planning to use a NTE585. The mosfet design is also out there and I'm considering it, but I think the diode is easier to implement.

Can you do an ups?

Pfft, reverse polarity protection is only for the weak.

From the beginning Hehe I knew that you got inspired by electro boom. My two favorite channels :D

Genau mir ist auch leider der selbe Fehler passiert, aber gut dass es GreatScott gibt!

Ft. Electroboom

uploaded 52 seconds ago, a comment from 2 days ago..........

Very well said @GreatScott. Good Job

Great vedio God bless you and your power supply. ....👍

I never had problem with reverse voltage

someone say hi to me.... Hi you person reading the comments!! have a good day

Nice demo. Will probably use.

FINALLY a new video from Scott

"What is the best Reverse Voltage Protection Circuit?" As it has been for years...A diode and a fuse.

Didn't watch the video yet. But... FULL BRIDGE RECTIFIER!

this is good for my knowledge electronic thank for this video hope you get more like this and stay well for your healthy

Thanks you great scott ! I am a big fan of yours! Can you make a voltage increasing circuit upto 1000v or 2000v?

Thanks for sharing this knowledge

7:47 I think this is the type of protection that is used in modern commercial car batterychargers (trickle loader), they don't charge when the battery is below a certain voltage, and the + and - outputs are shortcircuit protected, because they don't carry a voltage when there is no battery connected.

The diode in parallel is added generally to damp transient voltages which might happen during inductive loads... This parallel diode also happens to act as a reverse polarity protection. That parallel diode might be a TVS or a schottky diode.

Excellent solution, regardless of the voltage dropping which can be calibrated with a predefined fine tuning and clear the offset. Can you make a video about charging/discharging super capacitors?

Man you are incredible Thank you so much

I almost watched all of your videos, Not knowing Im not yet subscribe, and Now I subscribed that's why I made a Comment. HAHAHA. GREAT VIDEOS VERY INFORMATIVE AND HELPFUL. WATCHING FROM THE PHILIPPINES 😂

I always check each and every connection with my multimeter before plugging power in and I check the battery terminals for current directivity before plugging anything in. Quick, easy and as safe as you can hope for (unless you're wearing jewelry - Example if you have a ratchet/socket in your Right hand and touch your socket to either terminal and don't realize you're touching your Left hand's wedding ring to the other terminal you instantly die as the power moves straight across your heart [it's right between your 2 arms & hands!] but good luck convincing anyone to remove their wedding rings when doing such work!).

Thank you. Very informative video

Amazing video man! However you should have gone with the N-Channel MOSFET. N-Channel MOSFETs are generally way more cheaper, has a lower Rds(on) and gate junction capacitance. Means its cheap and power efficient. Keep making these videos man. I'm totally a fan. And I will see you next time!

Great video. This problem comes up often.

the best electronics video. great!

What soldering station do you recommend? I was looking to get a new one.

That heat sink looks Dope

This is really a useful video

I can't believe you spent almost 9 minutes on this!

Quick question: Why not use an H-bridge config at the output rails? To make sure that the + and - rails remains as is. We used that in our project. 🤔 Although I see that the power efficiency and voltage drops will be some considerations.

This is great! I just permanently modified my power supply by putting one of these circuits inside it. Now I’ll never have to worry about connecting it in reverse again!

This setup to this video is hilarious

Nice work as always. Could you please make a video on how to control 12v 10A DC motor without heating up circuit.

Nice video. Can I ask why you didn't use the exact same mosfet + zener solution for the battery but connect it at the drain instead of at the source?

There is another use to which an FET switch maybe used to good effect (no pun intended) and that is where you have a backup battery connecting to a circuit powered normally by an external source e.g. mains derived supply and where you want the battery to take over instantly on input power failure such as a bulkhead emergency light, especially as where I have one - above the fuseboard! An N-Channel FET can be used so that while the input source is present no battery current is used and no reverse current is possible either. Once the mains supply drops, the light turns on. Quite often, in fact usually, such lights are ALWAYS on and the battery constantly on charge and it just takes over on power fail. Not always what is required. Another similar usage is when an external charging voltage/current is going to be used to deliver charge current via an internally fitted DC-DC converter. e.g. external charge voltage of say 16 volts via a buck converter providing a 12.6 volt charging voltage to a 3S battery pack. In such cases the output of the charger (DC-DC Buck converter) cannot be left connected permanently to the battery since it will be receiving reverse voltage from the battery when the device is switched off and no external charge voltage is present. Fitting a single N-Channel FET with its Gate tied LOW to ground via say a 10k resistor i.e. turning off the gate, BUT a second gate resistor of 100k is connected to the INPUT charge voltage point of the buck converter. The output of the buck converter connected to the Drain, and the Source to the battery to be charged. When the charge voltage is present and the device turned off, the FET will turn on provided the input voltage of the buck converter is such that the difference between it and the output voltage is higher than the FET gate threshold, the output turns on and starts charging. I have recently used this exact technique to replace the old NiMh cells with Liion cells of TWO Dustbuster hand held vacuums and fitted internal charge circuits to them instead that operate in exactly this way so that when they are off and placed in their charge cradles (which can now be powered by ANY convenient 16-35 volt DC supply) they charge fine. As soon as they are unplugged the FET switches off and prevents the battery from reverse connection to the output of the buck converter which would otherwise drain the battery and also turn on the converter's output LED via the back-fed current!! This works GREAT. Especially as all the components needed were recovered from motherboards and suchlike! I included a BMS of course but also a battery status display with a button to manually show the state of charge when required but also it's auto switched by another FET when connected to the charge power.

Интересное решение с минимум деталей.👍электронный предохранитель и блок защиты👍

You had too much to drink. I applaude your candor!

Incredible ! It was what i was looking for to charge lithium battery with 220v to 5v supply. Because the 0.7v drop of the diode prevent it from completely charge le lithium battery. I hope the lower drop voltage of the mosfet will be ok !

Great Scott is really Great....

I have destroyed one of my boost converter(bought after seeing on your channel), by connecting 3.7V 18650 battery in reverse, that is why I'm here, but in my case, diode will be good as I want to operate a solenoid mechanism for approximate 2 seconds, thank you

An IRL5602S transistor can be used to protect a circuit with low power - 3.8 - 5 volts. It opens completely from the logic level of the signal (2-4 volts).

1 relé 1 tip 106 and few componentes more can make a short protection?? Nice vídeo