PWM VS Potentiometer! When to use which technique?

[@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

[@MrBiky]

watercooling resistors for better overclocking

[@chrisakaschulbus4903]

@Ξxodus for real?

[@minepro1206]

Lol

[@leocat2662]

Lol

[@akhilesh7313]

😂😂😂😂😂👍👍

[@mukhtarahmad3532]

🤣🤣🤣🤣

[@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

[@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

[@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!

[@goyabee3200]

This older video style was much better.

[@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 :)

[@Vnifit]

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

[@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

[@TwoForFlinchin1]

Thanks I really don't want to overcomplicate shit for a 5 volt fan

[@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.

[@aadarshshetty]

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

[@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

[@jgjgggjhn]

All of your videos are so awesome 👍👌

[@ifecojahs8151]

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

[@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).

[@metallitech]

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

[@bigjhims.k6654]

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

[@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.

[@heaanlasai866]

Idea for a project: PWM controllers use a manual potentiometer. But what if you want to control it using an Arduino or similar? Could you use the Arduino to control a small logic level MOSFET, which would feed into a simple circuit with a capacitor and a resistor? If you solder the terminals for this in where the manual potentiometer was connected, the pulse length would determine the voltage between the terminals, and thus affect the PWM controller as if you were using the manual potentiometer.

[@Dutch3DMaster]

You can use regular (BC547) low-power transistors for driving them as variable resistors. That's how I use them in a dashboard-simrig build for controlling the gauges from an Arduino. Low duty cycle/PWM frequency (I have yet to look at the output of a PWM signal of an Arduino with a scope, I have seen the Tone one) means the gauges shows a low value, and a higher PWM value means the gauge shows a higher value :) . You do need to use a fairly high value resistor on the base of the transistor in order to do this, you want to drive them like a variable resistor after all (I think my setup uses 10K).

[@Vangabonders]

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

[@RyanJensenEE]

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

[@Ystidan]

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

[@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!

[@octavio2895]

2:08 I heard you like mythbusters

[@jgjgggjhn]

👍

[@Strawberrymaker]

I'd say PWM is for LEDs the best anyway, because when you use your pot, you may have a linear voltage drop, but the brightness wont change in the same linear way ^^. ~STraw

[@syremusic_]

What software are you using at 0:50?

[@aayush3782]

Dmitriy B EasyEDA

[@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.

[@drfritz142]

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

[@JulioMatus]

your videos are always cool, congrats for your channel!

[@grins047]

Great demo of the difference. Thanks Scott

[@mauricioferrazzi]

I just came here to watch I don't understand nothing about what he's doing, but I have to assume you're so intelligent 👏👏👏

[@joshuanorris5860]

Mauricio Ferrazzi lmao Over my head too.

[@NicholasAarons]

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

[@nagabhushanabhat1710]

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

[@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.

[@BrutalGames2013]

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

[@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.

[@lilliampumpernickel9916]

haha 2:09, is that Adam savage

[@elektrolyte]

Brilliant. Excellent explanation. Thank you

[@FourthWayRanch]

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

[@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.

[@howarddetry9761]

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

[@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.

[@arielbluman644]

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

[@kushalbiswas7743]

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

[@guitarwhores753]

That's one way to bitch slap a hostile comment. Great vid. Sub'd.

[@duncpol]

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

[@gekesulen]

YES! +1 one for the adam savage quote

[@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 ?

[@s-napers]

So it'll work fine on bigger loads, you just need to set up a water cooling rig for your resistors.

[@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.

[@ljl451]

But the main difference between a variable potentiometer and a pwm is that the pot sets a constant voltage, while the pwm only sets the average voltage. For different loads with the pwm you might also need a low pass filter. Do you agree?

[@Dutch3DMaster]

Using PWM, the voltage basically doesn't change, each pulse is the same voltage, it's the pulse-width of each pulse that causes a particular response of the part connected to it. Small/short pulses mean a short amount of time in which current can flow, while a 100% duty cycle of the same signal (full on, as if the PWM circuit wasn't there) means current is flowing continuously.

[@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).

[@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.

[@basicelectronics1106]

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

[@vijankavcic2075]

for biger load you can use triac and potentiometer

[@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?

[@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..

[@rich1051414]

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

[@naitikshailendrakumaryadav2824]

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

[@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.

[@joshhagen4182]

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

[@massimogiardina9138]

Did you just do 7x2 on your calculator?

[@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?

[@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!

[@samad419]

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

[@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!

[@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.

[@EdwardNg190]

Hi GreatScott, I have some questions that I am thinking about it. I wanted to build a PWM controlled fan for my power supply's cooling fan, by taking the temperature of the mosfet in the power supply, it controls the duty cycle of the PWM of the fan. I have tested with Arduino to control it and it works fine. But I am not gonna put my Arduino board into my power supply. So what microcontroller do you recommend for this project?

[@MagiKnightOne]

ATtiny85 will do fine

[@MagiKnightOne]

ATtiny85 will do fine

[@MagiKnightOne]

ATtiny85 will do fine

[@MagiKnightOne]

ATtiny85 will do fine.

[@MagiKnightOne]

ATtiny85 will do fine.

[@klmbss]

Is it better to use potentiometer instead of pwm on led indicators? I heard pwm is not good for eyes.

[@jort93z]

depends on the frequency i would say. If the frequency is above 1khz there should be no problem at all. If you only have a PWM frequency of a few hundred Hz it could cause eye strain though.

[@commodoregamecube2200]

What software are you using for CAD? Proteus?

[@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.

[@DiegoSepu95]

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

[@kvlpnd]

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

[@therealb888]

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

[@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.

[@turkishwithemre]

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

[@jawadanwar6684]

Okay, I am never doubting German engineering again

[@iakovjack740]

Please upload a video or expain how to control led strip with potentiometer please!!

[@SaureHefePegorino]

+iakov Jack you dont. potentiometer for LED is terrible. use pwm

[@saizenki]

Circuit for PWM ? please scott !

[@josefaschwanden1502]

Timer 555 pwm or schmitt trigger pwm? Whats better?

[@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.

[@sandipkumarnandi]

can u create video on pwn based led driver

[@JakeDancel]

It sounds like he says "Poly-Charmander" rather than "potentiometer"

[@wi_zeus6798]

He's German, so his pronunciation can't be perfect. But I bet you don't talk another language besides English as he does! ;)

[@Microcontrol-ex1sb]

if you turn on captions, it shows "van" instead of "fan"

[@danfishermen5362]

Can you use a buck bost converter

[@Qxadinha]

And how use field effect transistor as load controller?

[@Erick-wj4vq]

"Remember kids, the only difference between screwing around and science is writing is down." Hilarious. XD

[@marc-andrebergeron6900]

You could use a computer spreadsheet instead of a paper / Ti-83

[@arnaudj2708]

At 3:00 I was like "come on man, stop hurting yourself and please use excel !"

[@mantasmeskis4687]

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

[@shibinshiji4671]

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

[@eirikmurito]

Great demonstration

[@guywhoknows]

This is funny and a old one. Perhaps a title of pwm v analogue and power loss calculations. I'm old and like analogue. Then have to apply this modern stuff to it. And then work it backwards so I know if it's right... How about you grab a Lucas voltage and current regulator and put them side by side with a modern take. ;)

[@harunhodzic1]

Do we lose the output torque with PWM when we try to reduce the number of rpm For example: the max RPM is 3000 Rpm, we use PWM and get 1500 revolutions. Have we reduced the torque on the output shaft?

[@Dutch3DMaster]

Typically, no, but it will depend tremendously on the motor technique. A fan is not supposed to have a lot of torque, but a DC motor will typically not suffer a huge amount of torque difference using PWM, where it will definitely with a resistor in line (even if you can find one that won't get flaming hot).

[@harunhodzic1]

@@Dutch3DMaster thanks

[@demm5]

Can it drive 160mA fan?

[@ericgfx01]

What program did you use to make your circuit schematic?

[@kerolox7929]

Eagle

[@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.