DIY FPV power filter for under $3

If you're flying an FPV RC plane or multirotor and find you have unwanted lines on the video image, you may want to add a power filter to you system.
This video demonstrates how a toroidal inductor and a capacitor can significantly reduce the amount of noise on the power feed to your FPV camera and thereby significantly improve the clarity and quality of the image it generates.
The Soft Ferrite Rings are available from HobbyKing for under $1 a piece (in a 5-pack) and you can pick up the required 470mfd capacitor from any number of sources - or just rip one out of an old computer or TV set. Just make sure that it's rated for at least 16V if you're using a 3S battery or 25V if you're using a 4S. And watch the polarity - it's important.
The enameled copper wire can be picked up in small reels from a hobby store or you can scavenge it for free from an old transformer if you feel so inclined.

[@hiwayM9]

I only recently subscribed... because I only recently discovered your channel... I have lost hours sitting here learning. Bruce, you are by far the most succinct, the most respectful, and the most enjoyable mentor I have ever had in this hobby... and you wouldn't know me if we passed on the street. Bloody damn fine work you do, and I am a better hobbyist for it. *on a related note- I bought a lc common mode filter on advisement when I built my mini 250 and I am glad. *on an unrelated note... I use the Naze... and that is a sweet FC, so based on the comments down there, I am looking forward to your vid on that. You may want to break it into 2 or 3 parts since it can get heady.

[@xjet]

Why thank you so much for your kind words, they are much appreciated.

[@chatwithpete2734]

Gratitude :) nice work!!!

[@SvenOkonomi]

Ive used these for years, this is one of the best tips you can give for FPV, especially when you are flying on a single battery. The pulsing ESCs induce a really nasty bit of noise.Good on ya, Bruce!

[@bgdwiepp]

Great video bruce! I think i remember mentioning inductors in another videos comments! Also, protip; put the toroid in the middle of the piece of wire and wind, it's quicker because you have to pull half the amount of wire through (distance), and you bend the wire strand half as much, fatiguing it less. Plus, half of the toroid is wound when you start the second half, holding it tight allowing you to pull the wire very close to the toroid, and thus more turns! Good video nonetheless!

[@zhenya1343]

I, for one, love the whiteboard thing. It's awesome to see the theory explained behind the application! Thanks again for this great tutorial!

[@midasg1]

I put an LC filter on my VTx power supply line today, and what a difference! I used to have horrible black lines all over the video signal when the throttle was beyond 25 %. But now I get a crystal clear video signal even at full throttle. Thanks a lot for the tip Bruce!

[@MyTechWebTV]

GREAT Bruce! I have learned more about the technical side of this hobby from you than from all other sources combined! Thank you for taking the time to educate once again!

[@beyondfossil]

Excellent demonstration with the oscilloscope. Simply excellent!

[@fokke1037]

Excellent, this seems to have solved my horizontal line issue on my boscam VTX / Runcam 2 setup. My video was clear, until I increased the throttle... ;-) I tore an old PC PSU apart, used an inductor (with copper wire already attached) and a 16V 2200 capacitor. Many thanks for explaining the background info, it's helped me a lot in partially understanding what we're dealing with here. For those that are wondering: I am running 3S, 12V is coming from my Matek PDB (with 12V BEC) . This is a safer solution in my opinion, for when I choose to run 4S Lipo's later on, I won't have the risk of frying the capacitor.

[@servoman11]

You Sir are the best teacher I have ever viewed on The Tube! Thank you for all of your excellent video's.

[@PauMallol]

Châpeau Bruce! Precisely considering to get a second power filter from Fatshark to clean up my FPV power lines but your solution is so much more sleek! And I even have the components lying around... :D Thanks, again, for your vids and, especially, your explanations: I like to know why things happen and how the solution works, not just copy the procedures. Happy flying!

[@davidringler40]

bruce by far your videos not only show us how to make equipment and explain how to make and why and what its does and how. that's awesome thank you and GOD BLESS

[@daretattoo1]

Started to LOVE electronics since I started watching your videos. Thanks for your educational and inspirational videos.

[@peaps]

Nice video Bruce. A lot of other sources suggest wrapping servo wire around the core, but on reflection, it makes sense that you'd get more inductance with more turns using thinner wire.

[@louletuga]

"just a short video today folks" ...16 min lol Keep them coming Bruce. Love your white board videos! You explain difficult stuff in a very easy to follow manner! WE WANT MORE WHITE BOARD VIDEOS!!! :)

[@EhnTeePee]

Also, I watch every minute, you are an excellent orator,sir.

[@EgoIsFlawed]

great video, excellent shop presentations, learning electronics has never been easier.

[@richa8383]

Bruce I've recently done some experiments with RL, RC and RLC filters at university, so I understand it but wouldnt have thought to use in this application. Nice work. Keep up the great ideas.

[@godsgifttocockpit]

Thanks again for the video! I only wish our electronics professor would've used some similar practical examples and analogues to explain things. We mostly did just the math around all this without really understanding anything what the circuit actually did or why we needed to bother changing it. Keep up the good work! :)

[@matrixate]

When you know what you're talking about...it makes sense. Good job.

[@hansleatherby1032]

Thanks for passing on your knowledge in such an easy way - keep at it Bruce

[@renoflash06]

Bruce, I find these educational videos great to watch. I probably would have paid more attention in my circuits class if the teacher would have talked about RC gear in his lecture. I hope you produce more of these types of videos. I really enjoy the white board videos.

[@tnicod]

Very interesting recap! It took me few years back into the basic electricity field! Thanks very much!

[@waspmeat]

What a lesson! Taking me back to Electrical Circuits 101!

[@The2ndKeepsUsFree]

Fantastic information and video Bruce! Great work as always.

[@MrHandsomejackuk]

thanks Bruce.... I wish i never went back to my afternoon lectures drunk.... when i did my HNC electronics....I usually fell asleep.. great information

[@stephenclute]

Love the videos, Bruce, been watching since my budget mini-quad build many years ago! I wanted to thank you for this video particularly, as I recently bought the Foxeer Arrow with built in OSD. Adding this style filter cleaned up the noisy video when powered straight from a 4S LiPo, while giving me my battery voltage on the display. Good stuff!!

[@bigbadalphawolf9330]

I like watching your videos. You are a great instructor. everything is broken down and you take us step by step explaining everything, which makes learning enjoyable. Thank You. oh, plus you're very funny.

[@MrCottonmouth]

I really like this video. Very good refresher course. Not only described how to build it, but also how it works. Very good easy to follow explanation. :) 2 thumbs up!

[@Walt1119]

Bruce Thanks so much, especially for the white board schematic and explaination!! My electronics has gotten really rusty, such great fun when you explain it all!!!!! W

[@3deeguy]

Thank you! I bought a cheap PAL camera and tested it on my NTSC TV (before I received my monitor in the mail) I thought the lines and the tendency of the screen to go black were the result of mixing 60Hz and 50Hz. When I got my monitor and tried to fly FPV I found that the monitor screen would still go black 'until' I pushed the throttle, and I still had lines. I don't have a scope so this video was really helpful.

[@fredbutlerfb]

try to use a non-blue/black screen to avoid this. like the cheap screen the quanum FPV goggles use :)

[@Masterpj555]

I really love your videos. I can place your channel right next to the eevblog, ben heck show and dangerous prototypes as one of my favourite electronics related youtube channels. Thank you for doing this!

[@alexadabic]

thanks man, i was stuck in this filter stuff till i watched your video. Love your videos, keep making them :D

[@keystonerenovation8687]

Hi Bruce! I would like to thankyou for the video. I enjoyed watching how you connected it to your QC and i absolutely loved the scientific explanation at the end. At first i was lost but now i am found and it's as clear as day or should i say as clear as a 12v FPV camera mounted with a 400mh conductor and a capacitor :) I'm new to the QC hobby and electronics hobby so i have my new favorite channel. I'll look fwd to seeing more videos like this one! Cheers mate!

[@Flash1940]

Good job Bruce....Everybody needs to know about an L..C filter. Maybe another winding right on top of the first...then you may haqve been able to use a slightly smaller cap. Saving some space,,,,maybe. I have some of those from Amidon that have different mixes for upper frequencies.....I have a homebrew converter that converts from 50MHZ to 14MHZ. Used a Grid Dip meter to line it all up.

[@zorglev]

Great video. A question was asked about stripping the lacquer from the enameled wire. I find furniture stripper containing methylene chloride works very well. Just a tiny dab is necessary. Won't work on epoxy.

[@jasoneyes01]

Love this guy,, a simple man with fantastic physics mind!

[@willywgb]

Hi Bruce. Great Video. Would love to see more Electronics Videos. Examples: Buck Converter design, ESC design, Antenna tuning. Cheers Bill

[@jfrede1976]

You can improve this a litte bit by inserting a diode befor the coil so that the Motors can't draw any current from the capacitor. Furthermore, you can add a small ceramic capacitor connected in parallel to the electrolyte capacitor. These capacitors can better smooth high frequencys.

[@Hotwire_RCTrix]

This is a great tutorial. Thank you for your time Bruce. 👍

[@grim-upnorth]

Great video, it actually inspired me to go out to the shed and make an inductor... I have a few ferrite torroids and some enamel copper wire. There's just one thing though, you glossed over how to actually "make" the filter. the science and explanation was brilliant, I understood it very well. but it would have been nice to see how you connected up the capacitor (i'm sure there's a right and a wrong way) and then how you would connect this in a real life circuit... still a great video... I actually do like the whiteboard stuff :)

[@MrCasehatter]

Dang Bruce I do thank you for the education electronics for Dummie's That's me I can trouble shot and change boards but now I'm starting to understand them, I like it, thanks again..!! Hey guys don't forget to go to his web site and donate to keep him alive and helping us...!!! Thanks and keep the education coming it's great..!!

[@Jimmehify]

Thanks bruce, as always informative and furthering this great hobby! I have no doubt that blackout will include this on their future versions as standard.

[@SmokinMesa]

Cheers Bruce. Every day's a school day

[@NormanLedoyen]

Great video of information Bruce. Please keep it up.

[@dave_s_vids]

Great video! Loving the electronics ones, keep them coming please!

[@TotallyGlitch]

As always, thank you Bruce

[@TheFarleyGordon]

Cheap as beans Bruce just love this stuff Thanks

[@KiyoCabessa]

Amazing Tutorial as always :) Thank you Bruce And greetings from Spain

[@didgydont]

Thank you for your wonderful explanation

[@Norminal1]

Thanks. It's been driving me nuts. I'll give it a go.

[@Burbsi]

today i remembered myself about ferrite rings and put them on the video cable - DON'T DO THAT GUYS - my video was unrecognizable, i thought my fpv cam broke. So ferrite rings are, just like xjet demonstrated, for filtering power wires, not the video cable itself.

[@RcBuddy]

"Bruce yet another great educational video." indeed +1

[@aboldy]

Great article. Really enjoy the way you presented that really made sense. Thanks

[@heiligcrt]

Another great video, thanks Bruce

[@cloudninefpv]

Awesome Bruce!!!! Thanks for the excellent vid

[@MrTaz0079]

Thought you said the QRX 350 Pro was going to be your next video?? You have been out flying and enjoying yourself.... The fun police wont like that.......LOL

[@xjet]

Yeah, the QRX 350 vid is taking a while to edit -- had to reshoot a couple of bits because of my damned microphone. I've done the studio/bench part, flight tests/vid should be done this weekend at the next meeting of the Forest View Model Fliers Club :-)

[@SYNFPVPILOT]

Fantastic video. Thanks Bruce!

[@maikel1707]

Thank you very much Mr. RC for the perfect explaining about this subject. :)

[@RenatsMC1]

I came a cross your videos and you explain similar as my physic teacher easy to understand and interesting to learn ;)

[@darrelldixon8248]

trinity indoor flying

[@ME-zu5kg]

Another educational Video Great going to use it as soon as i get a few ferrite rings. Also the Mice was acting up on the vid as I am sure you said Spasmodic.;)

[@andywonline]

Awesome video, as always. Thanks for sharing.

[@rick6633]

Always appreciate your explanations. Keep up the good work. Thank you.

[@SWFLJetSkiRiders]

Love your videos , keep it up my man

[@timomartens99]

Super explination! As good as always!

[@N7CX]

excellent demonstration.

[@lynx_nz]

Awesome video. Thanks for your efforts!

[@RakishRc]

I had the same problem with my 1500mw video transmitter I use for my rc car fpv with 1.2ghz video. I had the tx connected to lipo I use for my rc esc to power up via balance adapter. On high throttle I'd loose the video with black lines. I simply used a separate 3s lipo to power the tx and haven't had any problems yet.

[@zimmy1958]

great stuff Bruce. THANKS

[@fod3er]

That was a really great video to watch, Thanks for sharing your knowledge with us :)

[@liambowers666]

Bruce has cracked his glasses :( another great video tho! Going to make me one!

[@Autocharge1]

I will have to remember this if I get stuck with lines

[@oman636]

mate your a legend love the videos , keep up the swagger

[@mattb1967mb]

Dang you're smart... Love your videos !!!! 👍

[@jackheartpersonal2072]

ah Bruce ~ just a short video ~ 16 MINUTES ~ but worth it , Thanks

[@michealwithington]

I have been watching your video's since I started in RC and it has been a huge help over the past 3yrs, Also a kiwi. Good Value. Thanks.

[@MorRobots]

FYI If you don't mind paying a bit more, small high inductance inducers are easy to buy online or at places like radio shack.

[@xjet]

The only thing to watch is that you get one which won't saturate. You can get 400uH inductors as small as a grain of rice -- but they'd be next to useless in this application because they would saturate at the currents involved (as per the graph I put on the lower-right of the whiteboard) and once that happens they act just like a straight piece of wire.

[@MorRobots]

***** this is why we watch your chan!

[@roddysallie9861]

Hi Bruce. Great video again. But just one thing for idiots like me :-/ How exactly do you connect this up? A short followup video would be most helpful for all beginners Thank you for all the videos and help

[@blackmennewstyle]

Normally you should mostly plug your power filter between your power battery and your video transmitter but a lot of other applications are possible :)

[@roddysallie9861]

Ok. thank you for the advice

[@Hoverbot1TV]

Thanks Bruce making 1 right now,

[@DENMONKEY]

Excellent video.

[@stewjw]

I've been using these expensive LPF-01 LC Power Filters. I'm unsure what the inductor is in these I've never taken it apart. It would be interesting to compare Bruce's $3 LC filters to these $15 ones. Very nice explanation.

[@stewjw]

Another related effect is using capacitors to protect the ESC from the inductive effect (?) of long battery leads to the ESC for large aircraft. Not a problem for a Mini Quad.

Bruce - there is a mistake in your white board schematics. We do not connect inductor between battery and ESC (it will burn). We connect it before camera, not before esc :-)

[@xjet]

No, the schematic is correct -- the inductor connects between the battery and the camera. You will see that all there is on the right-hand side of the inductor is the capacitor and the camera. The battery is on the left of the diagram.

***** oh , ok :-) my mistake... thought the camera is on the left side. This 12V sign confused me. Sorry...

[@alexisrazon6239]

As always another awesome, educational video! I am almost confident in building one even with my zero electronics knowledge. Two questions though... what are the resistors for and what are their ratings? I want to get this right the first time. Thanks!

[@spocktra50]

TECH-NI-CAL :)

[@xjet]

:-)

[@snaprollinpitts]

thanks Bruce, I love when you show us the electronics and the theory behind it, great vid!!! a quick question about coil saturation, can you use a small board inductor as a pick up, and with a scope see the spikes or if it's saturated it should come up to a level and stop moving? what do you think? thanks again for your engineering expertise!!!

[@c0p0ut]

I love your videos. They have helped me so much in this hobby. Keep them coming! I just have one question. At 2:20 you mention the copper wire thickness is unknown but it will be added to the video. I'm having a hard time finding it. Can you tell me what thickness you used, and/or what range is best to use? I am about to place an enameled copper wire order and they are asking what thickness I need. Thank you!

[@danielreed100]

instead of wrapping wire from 1 end start in center of cut wire and wrap both ways it will reduce wrapping time thnx dan

[@pixelpusher3589]

thanks Bruce.......the great explainer

[@grahamhall1607]

very good just about my level. Enough info to be really useful. Thanks

[@icyburger]

awesome vid!

[@flymrc77]

Clever man.

[@bobot021070]

That is kinda Big help for a guy like me Whos into this hobby. Big thanks to you and hope u have more helping vids to come. Thanks Daddy white BEARD. 😁😁👍👍👍

[@JavierDiazMn]

Excellent video, thank you very much

[@mboiko]

It would be interesting to find the point where running a separate battery would make for better solution then a toroid/cap/etc....based on a weight savings. Would the toroid/cap solution always be the better weight saving solution, even on larger planes/MR configurations? Excellent video as always..

[@simonnaughton2272]

Awesome video ***** Sadly I'm only learning this electronics stuff as an adult, but better late that never right? Thanks again.

[@kkhalifah1019]

You can actually buy torroid inductors on the cheap on Banggood, something like $2 for 5 pieces rated at 330uH all nicely wound & ready to go. Saves you the hassle of buying and winding all that copper wire. Anyway Bruce... quick question... how do I know how much uH I will need for the torroid inductor?

[@PHILSWINGIT]

Hi Bruce love your vids but this one for me is a winner thanks mate

[@TeodorD]

Hello Bruce, love your videos .. keep it up. Was wondering does the transmitter need to have power filtration, or does that have it already on board? I know it can depend but just as a general rule:P Thanks ;)

[@PhilLucasVLOGs]

Very informative video. Thanks for putting it up. I understand that putting a capacitor in parallel effectively grounds the peaks in voltage due to the motors need for pulsed supply. Have you tried either putting the capacitor in series or and additional capacitor in series (in addition to the parallel)?

[@lolmadmaxlol]

Great video as usual :) Thanks for all your instructions, explainations and hints. But one short question. If i have a 5V FPV camera should I put the regulator before or after this LC-lowpass filter?

[@bigcountryforever]

what a great video very well explained :-)