PWM VS Potentiometer! When to use which technique?

Twitter: / greatscottlab
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In this video I explain when I like to use PWM and when it is useful to just put a potentiometer in series to you load. Both have their own advantages and disadvantages but none is perfect in all situations.
Music:
Killing Time, Kevin MacLeod (incompetech.com)

[@kuyanatnatdkrx7]

best science quote of the year : "remember kids the only difference between screwing around and science is writing it down."

[@natedagrate227]

+kuyanatnatdkrx7 Adam savage said that on mythbusters

[@kyanhluong]

+Nathan Healy On what episode ?

[@bman12three43]

one of the earlier one's I think. He was probably quoting him.

[@manuel8179]

that's true, Adam Savage said that

[@MattK2015]

mythbusters refrence

[@dimpelgimpel]

van

[@jort93z]

well, its still funny. Also, most germans do not pronounce it van because "fan" is used in the context of football fan or something similar in german as well and it is not pronounced "van".

[@kakeergodt4609]

Lol

[@jort93z]

@Markus Schnepf I am not sure what my intention with that comment was(check the timestamp) But i believe i meant that germans would know how to pronounce it since they use that word for football fans and such. You can't say no german though, he is german and pronounces it "van".

[@3poli]

In serious

[@MrBiky]

watercooling resistors for better overclocking

[@chrisakaschulbus4903]

@Ξxodus for real?

[@minepro1206]

Lol

[@leocat2662]

Lol

[@akhilesh7313]

😂😂😂😂😂👍👍

[@mukhtarahmad3532]

🤣🤣🤣🤣

[@Vangabonders]

Short and simple. I love your videos man. Very educational

[@JulioMatus]

your videos are always cool, congrats for your channel!

[@NicholasAarons]

Awesome Video Dude. Very well explained. Keep up the great work. Nick.

[@bansheedearg]

In German, "Vater" means "Father" but the V is pronounced like an F, so it sounds like "Fater". Or Volkswagon sounds like "Folks wagon" which is what it is in German, Folk's Car. Or Fokker planes, etc. That said, I have no idea why we're driving around in a Van with a 9V battery. Tesla should be shaking in their boots though.

[@benjaminfauchald2990]

This is also why you should know that Darth Vader was his fater from the first movie.

[@xgamerbih]

“Volkswagon” lol. VOLKSWAGEN!

[@big_o1952]

@@benjaminfauchald2990 wait what how how no what

[@DerrickWindsor]

Great series - I am glad I found your channel as I am always on the look-out for good tutorials to post on FB - my audience is mostly non-geeky, so clear explanations are always helpful! And I am also planning to post ARDUINO Nano projects. Cheers.

[@jgjgggjhn]

All of your videos are so awesome 👍👌

[@grins047]

Great demo of the difference. Thanks Scott

[@SteelSkin667]

Very informative, thank you ! I will probably use a potentiometer if I decide to do the fan thing, but now I know why PWM is so widespread when it comes to voltage regulation!

[@nagabhushanabhat1710]

good work man. all the best for future videos,👌👌👍

[@ifecojahs8151]

Thanks so much fro this explanation, I am an automotive technician, so I meet these things everyday, especially on late model cars.

[@Ystidan]

Your video are definitely more instructive than my electronic lessons at school. Thank you a lot. You made me want restart with electronic ;)

[@elektrolyte]

Brilliant. Excellent explanation. Thank you

[@DownhillAllTheWay]

That's a really informative discussion, well constructed. I particularly liked the comment "The only difference between screwing around and science is writing it down - but why, oh why does everybody have to put a distracting music track alongside their voice? Of all the lectures I have attended, I have never been to one where the lecturer switched on a music track before he started talking.

[@Dutch3DMaster]

BigClive doesn't use music :) . Though not a professor per se, but he does know his stuff.

[@abdelrahmangamalmahdy]

In this video, for the first time, I figured out that you're German and left-handed too.. no surprise you're a wonderful guy :)

[@metallitech]

Great video! Took me a while to figure out what this van was, lol.

[@donj.giovanni7551]

Very informative and educational. Many thanks! What do think about single transistor used as a voltage divider and its power waste? Thanks again!

[@TimothyJohnAguilar]

Hey GreatScott! I love your videos sir! I'm glad I subbed. PWM and Potentiometer are interesting and all but do you think you could cover some digital stuff like perhaps using a rotary encoder? To control something like a DC motor or a servo. Thanks in advance!

[@goyabee3200]

This older video style was much better.

[@RyanJensenEE]

Excellent video. Incidentally, you have great handwriting for a left-handed individual.

[@tristunalekzander5608]

Awesome video!

[@FutureAIDev2015]

Scott, I'm trying to understand a switching regulator system. From what I've learned, a switching regulator varies a square wave's duty cycle in response to a negative feedback signal with respect to a constant reference voltage (zener). My issue is, how would I set up this feedback network, and how would I adjust the oscillator's duty cycle without affecting its frequency?

[@BrutalGames2013]

Thank you for this informative video! Is it possible to dimm a COB LED using PWM ?

[@pierreaugustin154]

Great explanation thanks!

[@aadarshshetty]

This was a question I could not answer to my teacher at college and myself .... thanks Scott....

[@Vnifit]

Wow thanks for making this. Learned a lot. "The only difference between screwing around and science is that you write it down"

[@eirikmurito]

Great demonstration

[@abhayraj695]

you are GREAT tq for informations.......

[@kvlpnd]

+GreatScott! Which IC did you use for PWM output?

[@MoltenSamurai]

I really was wondering why the heck we would ever use PWM over potentiometers. I guess it was pretty obvious from the start, lol! 🤦🏾‍♂️ Helpful video

[@unglaubichuberlieber8048]

gut gemacht !!!

[@howarddetry9761]

What are those cables you used in the breadboard called? The one with pin like thingy...

[@wardb6539]

i'm searching for a solution the change my 'voltage in' of a my dummy load. the 'voltage in' is 54.8 V. max load is 4 X 50 W (a little more with ventilation, display, etc.). Any suggestions ? Kind regards.

[@ticktock8751]

thanks for the video, i have a hard drive box that works well but after some hours i am going crazy with the sound of the fan, and i did not want to put a big set of parts in the box to slow the fan but maybe just use a 10k POT maybe 2k Pot but dont want the pot to get hot

[@Dutch3DMaster]

In case of putting a potentiometer between the device and the voltage source, the heat buildup in the resistor that is a potentiometer is based on 2 things: the amount of voltage difference you want to create (in your case: how fast the fan is spinning) and the amount of current this device draws. The reason his quarter of a Watt set of resistors became flaming hot in the case of the LED strip is because there was a stupid amount of current (up to possibly around a full ampère) running through them all while also trying to limit some current from reaching the LED's so they would not shine as bright. Trying to regulate current/voltage with a resistor means there will be power that has to be dissipated in a way, in this case by putting all the power we don't want the device to use into an electronic part that has to get rid of the excess power by converting it to heat. In case of low-current devices this will typically not be a thing for small variations, but the bigger the difference between the device and voltage source, the more heat the resistor will start producing. Even if 0.25W resistors might be fine for a small variation, they might start to become reasonably hot when you slow the fan down more, because the power not used by the fan will have to go somewhere, in this case by being converted into heat. Sometimes you can feel this, sometimes you can't but the process is basically still there, just not detectable.

[@kushalbiswas7743]

Scot, can 555 ic change the duty cycle, or it just squish and expands it???

[@stevetobias4890]

Excellent video, I keep PWM was the better way to go to get the maximum from the battery and to reduce the potentially dangerous heat buildup.

[@Dutch3DMaster]

That reduction can also be achieved by using much higher power (.5 1 or even 2 W) resistors...in some cases PWM might not work and a resistor is, unfortunately the way to go and you will need those high resistors. I'm impressed that his didn't start smoking seeing how hot they were actually... From work I managed to score 3 16 Ohm, 60W resistors (no clue what they were in, but oof they are beefy).

[@programm1001]

Thanks for that nice Video!

[@MarkVanVasey]

hey Werner Hertzog! great video.

[@sankarmondal89]

can you make a video on a project that is included, NodeMCU + Relay module + Robotdyn AC light dimmer + Blynk? or can I have the coding? I'm trying to make a project like that but really poor in coding. Will you please help?

[@bigjhims.k6654]

One day I want to be an electrical engineer, I'm just a beginner but this channel has helped alot

[@curtisdesselles8691]

Hello, Love your videos. I have a question. I am trying to make a power supply from my mains (110 v, 60 Hz). The output must be adjustable from 1 - 60vdc. I will use a transformer and full bridge rectifier. I need to control the voltage some way. I also wanted to switch the voltage with a MOSFET using an Arduino to get an adjustable PWM and frequency. Am I on the right track? Thanks, Any suggestion?

[@andruloni]

Mind the fact that my electronics experience is limited to soldering a couple (literally, if I remember right) of kits. Once you get the mains to 60V and rectified, this seems to be a job of a step-down regulator. A full Arduino MC might be too much for the job, but if you find uses for the other pins of it (like a fancy light show⸮) it might be simpler overall.

[@commodoregamecube2200]

What software are you using for CAD? Proteus?

[@PunitJain8695]

"The main difference between screwing around and science is writing it down" - Great Scott clearly what makes it great. :) BTW, that goes to my wall of epic Science quotes

[@ramakrishnamishra8179]

Dear Sir, I wish to ask a question. I wish to vary the intensity of 15Khz RGB lines, what should I use? Potentiometer or anything else? I want to keep the circuit really simple without any loss of quality..

[@MarkJay]

GENIUS!

[@samineni100]

thanks bro!

[@freetubemovies.644]

Hello , I really liked your video sir ! 💜💜 Sir , actually I need your help ! sir , I am working on a project where I have to use a suitable potentiometer that can oppose 2 Amperes of D.C current !!! I have 6 A of D.C current and I want to use 4 A of D.C current by stopping 2 Amperes using a potentiometer or anyhow possible ! 6-2 = 4 ( 4 Amperes I want to achieve). Can you please tell me which potentiometer should I use or how can I do that anyway ?

[@gekesulen]

YES! +1 one for the adam savage quote

[@myintnaing2470]

Yes. Clear. Thank

[@NYCSigmas]

I am working on a laptop fan. I could really use some help. My laptop fans are running at full speed. It is a motherboard issue but replacing the motherboard could cost me over $500 USD. The laptop is ASUS ROG Strix GL702ZC. I bought some pin adapters so that I don't have to destroy the fans to splice the wires. I connected a 10K ohm potentiometer. I may need some assistance.

[@HamzaBenHassen]

Great job Great Scott you really are an inspiration . it would be really cool to see you make an PoV Display with few rgb Leds . keep on the nice work :)

[@greatscottlab]

The POV Display has been on my to do list for quite some time. It will happen soon.

[@abdulkarimhalai6708]

@@greatscottlab so it did finally happen! :) Loved it!

[@basicelectronics1106]

If we connect a resistor in series...will there be enought current to drive motor..??

[@MertYerlikaya]

This is great.

[@joshhagen4182]

Could i make a heating circuit that measures temp and adjust the heat using a pwm on an arduino?

[@ericgfx01]

What program did you use to make your circuit schematic?

[@kerolox7929]

Eagle

[@abhijitrashinkar]

Excellent

[@bobbennem2765]

Could you do a version of Make Littlebig Lamp that doesn't use NTE2013 IC chip. If you haven't seen the project search it up in KZbin it's a good project but can't get hold of the NTE2013 chip Pleeeeeeese help

[@greatscottlab]

Bob Bennem I am familiar with the project. And I really like the idea. But instead of building a new lamp I would "hack" an existing one to use LED lights and the dimmer circuit.

[@embededfabrication4482]

what is the best way to control a hub motor controller with an MCU? direct PWM or use a digital potentiometer?

[@mahmoudlastname121]

i like the way you thinking

[@mantasmeskis4687]

GreatScott can you make 300a pwm speed controller for 36v motor

[@dirtty3486]

Great video... question?...I want to use only a resistor to slow down the speed of my fan.. the spec is 12v 1.60 amp.... the power source is a 550 watt power supply.., how much ohms and watts should i buy. want to reduce speed at 25 to 50 % thanks...

[@Dutch3DMaster]

Forget watts in resistor calculations. Depending on the amount of current you will have to limit the fan to in order to reach a 25% to 50% reduction in speed, you will have to try out multiple resistors. Let's for simplicity say that in order to reduce it's RPM by 25% we need to reduce voltage an equal amount (which obviously is not how things work, but OK). Just for the sake of simplicity we also consider the resistor to be a perfect electronic part with no imperfections, and in order to reach the reduction, we can reason that at normal operation, the fan uses 19,2W of energy (12V x 1.6A). In case of a fan reduced in speed by 25%, we end up on (roughly) 14,4W (9V x 1.6A). That means that almost 5W's of energy (which usually is much more than people realize it is) will have to be going somewhere, which in this case will be a heavy, expensive 7.5W resistor (you could use 5 but it will get quite warm due to being on the exact limit of it's power dissipation).

[@duncpol]

Would Arduino nano be even more efficient in PWM creation than 555 timer?

[@DiegoSepu95]

could i use a 1Mohm potentiometer? for pwm with timer

[@professorbuffet]

Hey nice video. But i was wondering if you could make a video on how to increase the output of a signal? thanks

[@Dutch3DMaster]

A power transistor or a mosfet that you feed the output from the PWM circuit.

[@ABaumstumpf]

by the looks of it the thing wold be more efficient if you used 2x NE555: The current-draw is linear with the supply voltage, at ~5V input it is down at ~2 mA, at 9 V it goes as high as 10 mA. So if you used a 2nd 555 to generate a 5 V supply, even with the extra components needed, you would likely end up under 40 mA. Also - how well would it work if you used a comparator to control the mosfet? A simple voltage-divider for one input, sense-line for the other, and convert the Mosfet PWM to DC with a capacitor.

[@lilliampumpernickel9916]

haha 2:09, is that Adam savage

[@therealb888]

What's up with blue vs green vs brown resistors.

[@Hakeeeeeeem]

Omg u r a genius, how u r not my friend!!

[@tristunalekzander5608]

It's really hard to find cheap 220 ohm potentiometers for some reason, I see 10K ohm and higher though everywhere. Would a 10K ohm resistor work well with a very small voltage? Like 1.5 volts from a AA battery?

[@Dutch3DMaster]

Depends on what you want to do with it. The voltage source in your case is also really low in value, so the current limiting a resistor of 10K would do along with the voltage drop the resistor causes would leave you with little current to work with, which is to say if you can find something that actually works on 1V.

[@naitikshailendrakumaryadav2824]

Please make video on inductors design and non isolated dc dc converters

[@Passco666]

+GreatScott I like your videos. They are very well prepared. But if you should use more seconds for calculations. Because sometimes you are too fast. Can you recommend me some page where I can study about calculation of electronics? Im newbie and I need something like you are doing in video.

[@drfritz142]

"remember kids the only difference between screwing around and science is writing it down." i love it

[@josefaschwanden1502]

Timer 555 pwm or schmitt trigger pwm? Whats better?

[@klazzera]

in short, potentiometer adjusts the voltage/power at the load by spending the rest on itself.i learned this by burning up a few potentiometers. but still, i sometimes use high wattage potentiometers for the sake of simplicity and the power loss is not important.

[@arielbluman644]

mjlorton talked about TS555, that should consume much less power, should be around 150uA in 9V.

[@frecuenciajuaniyo]

nice video

[@FozCooled]

Could you make a video to control 48v fans like sanyo denki

[@rahulbindhu]

Golden days

[@mrmshifan]

Thank you for the explanation. I built the circuit but found not much difference with a variable resister. So I scrambled the circuit. Guess I have to build it again. Tq

[@Dutch3DMaster]

Some PWM circuits will require a big value potentiometer in order to see a big difference in output. One that I know uses a 100Kohm one, with a 10K one the difference is minimal, noticeable, but minimal (in my case it's used to control the backlighting of buttons in a dashboard-simrig setup).

[@SidhuBurre]

Hi Scott I love your video tutorials. May i know which type of bench power supply you are using?

[@greatscottlab]

***** ELV DPS 7000

[@Mandrag0ras]

GreatScott! How much did it cost?

[@lipelego22]

+Mandragoras google it you fool! lol

[@Mandrag0ras]

Lightning555 I did, you fool, but google won't tell me. It's either a rare or old model. Most results are in german and google translation is just atrocious.

[@samad419]

"maybe subscribe, its all up to you" I like that

[@syremusic_]

What software are you using at 0:50?

[@aayush3782]

Dmitriy B EasyEDA

[@demm7777]

Can it drive 160mA fan?

[@massimogiardina9138]

Did you just do 7x2 on your calculator?

[@danfishermen5362]

Can you use a buck bost converter

[@rich1051414]

How do you run your van on a 9v battery?

[@sandipkumarnandi]

can u create video on pwn based led driver

[@ivanpahl9861]

From where i can salvage transistor for my 12V dc motor i have B20K90 potenciometar, and on any curcuit board thath i salvaged it didn't sayed voltage of transistor just some numbers i just need speeed control on my 12V DC electrick motor and thats is pritty much, sorry for my English and spelling. Can someon answer me pls. tnx :)

[@arthurgoethals5308]

type the numbers in google and search for the datasheet, there you can find the max. input voltage

[@cal8414]

get to the choppaaaa

[@ms2649]

is there a to make an esc from a arduino

[@ambaoutomobileworkacandele9371]

Can you make a megnetic control servo tester please help me

[@lochinvar00465]

I was playing around with speed control of a propeller motor for a model boat. Using a pot, it would slow down to a certain point then suddenly quit. But, with PWM is slowed down smoothly until it was just a slow crawl. Imagine making a toy motor turn smoothly at 60RPM or even less! The fact is, when it gets each pulse of current, it also gets full torque during that pulse. When the pulses are fast enough, it appears to be smooth. My vote is for PWM.

[@benkrege2135]

you're probably using a log pot - use a linear one

[@Dutch3DMaster]

@@benkrege2135 No, that's not it. Most motors (especially cheaper, usually brush-ones) will have a stall voltage limit which will cause the voltage supplied to be insufficient for enough current to make it turn and have another successful turn be initiated. A linear pot will probably then show the same behaviour, except it will show it at a different point when rotating the axes of said potentiometer. With PWM however, the voltage provided stays the same, but not the time it is applied. If the motor wants to turn because of the higher voltage, it might see a small amount of movement and if the frequency of the PWM signal is high enough, it will keep functioning at much lower speeds: the voltage required to push current through the device is, after all, still there.

[@xymaryai8283]

why do some instances of PWM control not allow going close to minimum load, while voltage control will scale all the way down to minimum load? example, in my pc's bios fan control, i cannot set the fan to stop when the temperature is under control when using PWM control, but when I use Voltage control I can

[@Dutch3DMaster]

Maybe because some of the fans do not support PWM control, but do support voltage control (best way to tell is if the fans have 3 terminals: that's Voltage controlled fans, and 4 terminals is PWM controlled). Some motherboard controllers also need to be explicitly told to come to a full stop under a certain temperature threshold and won't do it otherwise due to reasoning that a fan stop can mean a failure of one.

[@shibinshiji4671]

Please send me the circuit diagram details of that 9v fan

[@Qxadinha]

And how use field effect transistor as load controller?

[@MitgliedT5]

I need some help here: PHANTEKS PWM-Lüfter-Hub is a pcb with fan headers for 3-pin casefans, which are controlled via the pwm signal of the motherboard header (4-pin to 4-pin) and for additional power (the motherboard header does not have enough amps) there is a 2-pin to molex/sata 12v..... But this thing costs 20 bucks ... and it can't be so hard to build something similar, but there is no scematic for that pcb neither i'm that into electronics, that i could tinker something like that hub out.... Could anybody help me ? @GreatScott! +GreatScott!

[@Korystuwatch42]

In my example I have a red 2,2V 1A LED, and I want to power it from a single li-ion cell which voltage is 4,2V. I afraid to use PWM, because it seems that in the higher state the current will be way too big... Should I worry about that?

[@Dutch3DMaster]

You will definitely want to current-limit your 2,2V High power red led anyhow. Some PWM circuits suggest doing away with the resistor but that's not how things work: at 100% duty cycle (full on, basically) you will break your LED if you don't use a current limiting resistor. And a well charged Li-ion cell will not be at 4.2V, but 4.3 or even 4.35.

[@turkishwithemre]

My question. Why we need also PWM if we have adjustable power supply? This is my question i wonder a lot.