Electronic Basics #20: Thyristor, Triac || Phase Angle Control

[@bdh4rd]

Electrical Engineer here and I thoroughly enjoy the videos you post! Thanks for the good tips and refreshers!

[@greatscottlab]

Thanks for the feedback :-)

[@Afrotechmods]

This is my fav of your videos so far. Well done!

[@0Bariq0]

+Afrotechmods My 2 favorite channels on youtube. yours and greatscotts's. keep up the good work.

[@greatscottlab]

+Afrotechmods Thanks

[@atankent]

Same. Afrotechmods and GreatScott are the best!

[@ChathuraJayasundaraIMD]

can you too make a video on this topic please

[@kaustyagi]

chutiya hai tu chup baith

[@ollythebest94]

This video was a little bit too fast to cover the subject

[@magna59]

I think this guy is very good , but I think you need a degree or two to keep up with him .

[@shanmugapriya9349]

Yes it was bit fast

[@abizhar-7583]

agree.

[@potatotech7378]

all i understood was when it hits zero somehow it gives a signal of like 5v

[@oOcitizenOo]

yep, it was difficult to get to the point of the theory exaplined here at first, but if you watched this video three times then you could understand the basic concept (that worked for me)

[@mennims]

Let's get startedt! Been watching you since about 2014 maybe earlier. Love how much happier you sound in your newer videos. You seem like a sweet person, I hope life is wonderful for you and thank you for all the information

[@ferarry13]

i understand maybe every third word that youre saying when you get into electrical stuff but still watch ewvery video. good work man!

[@greatscottlab]

+Syko That's the spirit ;-)

[@vidrogic1499]

same problem, but gret videos

[@matchlesmage0260]

I understood nothing in this video

[@BoomBrush]

wow this video went over my head. im going to have to watch this a few times haha. maybe when its not 2am i should rewatch it :D

[@yashdodia8048]

I WAS FINDING A VIDEO THAT COULD HELP ME TO FIGURE OUT THAT WHAT IS DIFFERNCE BETWEEN LATCHING AND HOLDING CURRENT AND FINALLY I GOT THIS ONE. REALLY SCOTT YOU ARE GREAT👍

[@jordanjohnson714]

I started looking at this video, and noticed KZbin made me dislike the video. I never clicked the dislike button. Of course when I realized this, my mouse traveled at 99% light speed towards the like button, and the table broke from the force of the left click when the mouse was over the like button. I proudly saw the dislike counter go down 1 and the like counter go up 1. You make good videos!

[@eddyfuchs1]

Damn, i really learn much in this videos since #10 or so. I really notice that you started out pretty self-tought and now learn stuff at University, i like it

[@edwardhammock24]

Great video covering some advanced content. This is how the main propulsion motors on warships are controlled.

[@voltlog]

You got a new oscope, nice one!

[@greatscottlab]

+VoltLog Thanks

[@mouli570]

But this one is 13000 USD. Holy Moly!

[@VoltageGuy2000]

My favorite channel on KZbin!

[@alvarogdb15]

Being a Mechatronics student myself I find this video very useful. thank you!

[@CraigMansfield]

I have no idea what you're talking about, but I admire your knowledge and I like your accent and videos. I'm trying to "tap" a 16v power socket on a turntable, so I can run an LED strip from it, but it seemed to destroy the electronics.... unless I destroyed them by trying to solder a power jack off the LED circuit board. I'm going to try one more time, then probably use a 12v battery. That's the level of my electronics :D

[@semidemiurge]

This video demonstrates a high level of thought (and effort) went into the pedagogy. Excellent, and your efforts are very much appreciated. Now I must increase my increase my Patreon support :-)

[@greatscottlab]

+semidemiurge Thanks for the support ;-)

[@aursi63]

Your oscilloscope is simply awsome

[@leonelgouveia7573]

I discovered tour channel only 4 days ago, you're amazing, keep it up :)

[@arifahmed5035]

your teaching is awesome You may be a great Engineer

[@dalenassar9152]

Whenever I plug a component (like a TO-220) into a breadboard, I always use a pair of small needle-nosed pliers to bend the pins of the component 90 degrees first (on the pin axis), so that the component will slide nicely into the board (like a wire) without any damage to the component OR board--What do you think. Thanks for all the high-quality videos, too!!!

[@onjofilms]

As a 30 yr tech, these are great refreshers.

[@agstechnicalsupport]

Very good video illustrating the use of thyristors and triacs in phase angle control for light dimming applications.

[@thomasr1051]

In my 3rd year electrical class watching this instead of my teacher. Time well spent

[@jakelittle8098]

Nice!!!! I have a printer I tore down for project parts (HP LaserJet 1012). It has a circuit straight off of the mains voltage (120v/60Hz) that consists of an inductor-HV film capacitor-Triac (BCR8PM) w/ Opticouple (3SD21)-feeding into a 24vDC/240vAC 10A Relay. The circuit feeds the heating elements of the "ink setting" system. I've been scribbling all over this PCB trying to figure out how this 'triac thing' works....Then, in a break from my frustrations...you read my mind, mid project, and I got schooled ;)

[@LeoDDJ]

The whole time I heared ElectroBoom in my head saying: "FULL BRIDGE RECTIFIER!"

[@Enigman42]

Olayı aşmış o kadar profesyonel cihazları var ki ellerinde gece elemanları önüne bıraksan sabaha kadar proje devre hazır şekilde

[@mlikihazem]

Wow very good explanation, it's useful for both experts and beginners. Good work and thank you for your efforts.

[@greatscottlab]

+Mliki Hazem Thanks mate ;-)

[@hayel2015]

You are a great engineer. 💝💝💝

[@bikefarmtaiwan1800]

Interesting take on SCR control. What advantages would you say this rather involved method has over the original three or four component control circuit used most widely? You are a great teacher and lots of people are interested in this subject so I am curious why you did not also mention the simple way to control an SCR with a variable resistor, a fixed resistor , a capacitor and a diac ( The diac is optional) Thanks for a very interesting and informative channel.

[@latos_.salah282]

Thank you for the lesson fast thinckers understand...

[@МирославВучетић]

Awesone,LOVE your Electronics basics!

[@greatscottlab]

+Miroslav Vučetić Thanks

[@speedsterh]

Very interesting video for beginners like me (still, it's very dense and would need some further study to fully understand what you say). 17 people not liking your video ? Why the haters ?

[@sivaneshm9288]

Well done Scott.

[@LeoDDJ]

I hope, I overlooked something, but: An Autotransformer is not an isolating transformer. One of the contacts is connected straight through, while the other gets transformed. Which means, if you connected live and neutral on the input side in reverse (or plugged the plug in the other way around) you would have 230V live mains on one end of the output cable (and 225 to 235V AC on the other (differential being only 10V of course)). But the 230V are still earth referenced, so current would still flow through you like touching a live wire!

[@greatscottlab]

+LeoDJ True. I always check the wires on the input beforehand.

[@omprakashtiwari9492]

sooo nicely explained thanks waiting next one

[@leonamferreira8053]

This is a really mind blowing video!! Thanks so much for sharing this valuable knowledge! Im using your idea into my final course work. By the way, one thing I would suggest is to change the map function on your code. The potentiometer is being mapped from 0 to 10,000 microseconds (which corresponds to 1 period of the 60 Hz signal), but Arduino nano is getting the zeros in 120 Hz, because you rectified the AC signal. Then, instead of mapping from 0 to 10,000 I would suggest you to do it from 0 to 8333. That helped me here :)

[@leonamferreira8053]

I've modified the code again. I mapped from 1000 to 8000. I've put 1000 because arduino needs to wait the 1ms pulse from the digital input 2 and decrease to 8000 to avoid crossing the next pulse.

[@andrewwhite1793]

Hi, thanks for the video. However, touching the output of an autotransformer is potentially FATAL. This is a video about BASIC electronics so will be watched by beginners. A lot of explanation is really necessary first.. This is NOT isolated from the mains. It assumes that the Neutral is always near earth potential and that every mains installation has the Live and Neutral the correct way around. I have used an autotransformer in an AC test set-up but used a isolating transformer on the mains side to keep me safe. Why not use a transformer from a old wall adapter? This is much safer and more readily available to the hobbyist?

[@andrewwhite1793]

Max, Your transformer is NOT isolated. That's what the "Auto" in the name is. Your good quality auto transformer has its circuit diagram shown on the front panel to remind you. Test it with a Ohm meter.. Your otherwise excellent video is likely to be on KZbin for many years to come. Please consider re-editing it before someone copies you, but gets a shock. You have responsibility to your viewers, not to mention liability.. I am not the only one to mention this in the comments. Don't assume that we are all novices out here

[@oniruddhoalam2039]

GreatScott already talked about it in this video:m.kzbin.info/www/bejne/qqPQqa2Li7llm6c. What he tried to say in this video is that there is a safe voltage between the outputs of the autotransformer.

[@norlure]

Hello Scott ! So the yellow wire goes to.......LOL............I love your video keep up the good work.

[@jainvibhore1997]

I was waiting for it for ages... Thank you!!

[@manassehabraham5589]

Preparing for my SEM exams watching GreatScott 😂

[@zodiacfml]

This is way a lot better than my college. :(

[@mayankanand1379]

hey scott.... can u make a video on controlling 220volt AC fan speed controller using triac or thyristor and arduino...

[@SirDella]

@Richard Vaughn You can control the speed by lowering the torque just fine, ac fans do it that way, and I've seen fans that use dimmers to control the speed, creating a variable frequency sine wave would be overkill for just a fan

[@wiilliiamparker5216]

sometimes i forget you are from germany, but underlining with a geodreieck reminds me that every time.

[@idjasurayt8486]

Scott thats a wonderful video but i think u should use a snubber circuit RLC if we want to controll an inductive supply

[@wrathofsocrus]

I don't understand how there are 21 people that hate technology enough to give this a thumbs down, yet they used a computer long enough to make it here and give a thumbs down.

[@Aperson-sv2hc]

Ikr!

[@thedankoona_5854]

maybe they dont like the lession

[@RsGOD-if9rs]

+wrathofsocrus they just dont beleive in time travel. very sad indeed

[@xenolithhh]

It's actually 45 people

[@debashisdas7557]

+wrathofsocrus or This Can be a fact That thay consider Good as Bad and vice versa.....ooo wicked

[@jimadams2473]

Nice instructional video!!! Very well sequenced. I learned a lot. Thanks

[@bigbread9000000]

Love what you do, you just need to slow down a notch

[@arunkumarshreevastava6652]

In circuit at 4:00 , the resistor going to the optocoupler (4N25) is only 165 ohm which will only drop 8.25V when 50mA flows though it leaving 4.65V (12.9-8.25) across the diode of optocoupler which will destroy it as per the datasheet. So my question is how you calculated the resistance value for the optocoupler, are you using the peak voltage or RMS voltage because in both cases the resistance value doesn't match my calculation.

[@MarcelHIC]

Don't know what he did. Datasheet says 10mA typical LED current. So the resistance value for the optocoupler (LED-side) should be R=9*sqrt(2) V / 0.01 A=1272 Ohm., right?

[@EmbeddedClub]

Great of GreatScott!

[@ganeshsubuddhi1432]

I need iot based ac voltage control project can u please do video using nodmcuesp8266

[@methuselahkhan2213]

Really helps to understand electronics. How would you make a home power conditioner to enhance protection for equipment ?

[@thegreatleo2003]

Please create video on controlling AC motors using Triacs!!!! Details on Snubber calculation would also be very appreciated!

[@whitefields5595]

Can you do an example with trailing edge switching so you don't start with the large pulse of leading edge triggering. Intuitively it appears that this is kinder to the load

[@pablo_costas]

nice vid ,its good to remember theese things

[@matheusgolz5361]

Autotransformers do not provide electrical isolation from the mains. How did you probe the thyristor in the vídeo (03:17) without shorting a phase to ground trough your oscilloscope? I'm currently having problems with this limitation but can't find a easy solution.

[@inductr]

Maybe you sorted his out. You could connect an isolating transformer before the autotransformer. If you have two transformers 220/12V put them back to back and this provides actually double isolation. Then probing is totally safe!

[@t1d100]

What would be the model numbers for a typical jelly-bean thyristor and triac to buy to learn with? Thank you.

[@ricardosanjay38]

At around 3:15, you said 9V RMS. I looked it up and learned a bit about Root Mean Square, but I'm having trouble understanding it. Perhaps you could do a video on that?

[@greatscottlab]

+Ricardo Sanjay I put it on my to do list.

[@arv1ndgr]

Well done! Keep such basics coming! 👌👍

[@CodeCatProgramming]

Will you please show how to demagnetize a magnet with TRIAC?

[@bhavinrathod406]

hey Scott, I have tried to built a dimmer as fan regulator , as I am from india here we using 240v and 50hz ac so first I stepped it down to around 12v ac and fed it to full wave rectifier so and then connected + terminal of bridge to pin of 4n25 via 1k resistor and pin2 with (-)bridge , I am using pic microcontroller all is working fine in Proteus simulation , after detection of falling edge of interrupt firing 500us pulse to moc 3021 pin1 so according to theory I hoped to get around supply ac but in result I am getting 170v only , result is not according to theory but if I fed continuous 5v to pin1(moc3021) I get full ac supply , I am so stucked so can you tell me what is the reason?

[@dalenassar9152]

...just wondering, when you are going to make a TO-220 type case-compatible three-pin package that is easy on breadboards--just get a pair of needle-nosed pliers and twist the pins 90 degrees and they slip into the breadboard EASIER than a 1/4 W resistor!!

[@bhargavarajeswaran1784]

Thanks for making the video.

[@craigrotay3732]

Excellent tutorial!

[@szabojozsef7873]

Hello. With zero cross detection AC regulator I would like to control welding transformer, but I saw the scope that for example 50% switch the transformer alwys will get the maximum voltage at turning on. It would be better to turn on at 0V and trn off at some point not vice versa. Can you please help how could I do that?

[@Shest00]

Hello, your videos are great ! I was thinking about one project if u can demonstrate kr at least talk how to make-turning on a car with some kind of remote ? A real car. Thanks ! Keep publishing :)

[@oneproductivemusk1pm565]

You need to revisit this subject again but this time you must add a LPF to the output of the TRIAC am curious to see how the waveform would turnout.

[@TheSupertecnology]

not a full bridge rectifier, but a FULL BRIDGE RECTIFIER!!!!

[@MechanicForGMCCars]

Hello I have unusual question wuld that circuet work with pick up coils found in distributors? I have for days problems finding corect circuet to interupt pick up coils going to ignition module . So any help please? Is there specific frequency/voltage range that needs to be known first to make centrain circuet and how does the calculation is done?

[@NourMuhammad]

I see you have got new oscilloscope and also with touch screen :D congrats

[@TheHarinhulk]

Hey I have a doubt .. why not just directly feed the 9 V AC voltage to the option isolator? You'll still get a approx. square wave for the positive cycles and you can use the state change triggered external interrupt in your Arduino ....

[@coolaj86]

If you take a look at the detailed symbol of an opto-isolator you'll notice that it has a light emitting diode on one side ( en.wikipedia.org/wiki/Opto-isolator ). Depending on the rating, an AC signal may blow out the diode. Otherwise it would only respond at 60hz (only half of the wave above 0v) rather than 120hz (both halves of the wave).

[@paulmeynell8866]

A brilliant video, I have been trying to,fix a dimmer lamp. Could not find a good description of hoe it worked. Could you advise how you measured this with a scope, as I am not sure on ac where to connect the ground clip.

[@Taran72]

great explanation! thanks. A very helpful video!!

[@TheVideotubo]

The TRIAC latch signal, (OUTPUT from arduino), stays on after 'zero cross + 10ms'. The TRIAC turns off around each zero cross, obviously, but is it ok to leave the gate on all the time?

[@markusstaden]

So you basicly build a solid state relay and controlled it with an arduino?

[@Vodnik110]

speaking about a power drill with controllable speed, is there any way you could make a functioning one out of mostly parts you can get around the house? a techy...house....

[@greatscottlab]

+cameron bobak I put it on my to do list.

[@TechInventorAman]

hey great scott the video was great but the explanation was less and tough to understand i think there is a need to make part 2 of it ...consider thinking over my suggestion

[@greatscottlab]

+Tech Inventor Aman There will be no part 2

[@VidarrKerr]

@@greatscottlab Well, that sucks a lot.

[@monelfunkawitz3966]

@@VidarrKerr Not really. What would the part 2 be? He pretty much covered all the basics to get you diving into it.

[@VidarrKerr]

@@monelfunkawitz3966 Yeah, diving into other peoples' videos and writing. He could have made a part II for his fans/followers, so we don't have to go elsewhere. That's just good business.

[@beatlespennylane19]

Thank you very much for this video

[@mixtermuxter8602]

I didn't get it. What does a Thyristor do? I only got the controllable diode part. But what does that mean? i am lost...

[@konstantinostriotis7142]

Are you able to dim a LED lamp with this circuit?

[@aneeeessshhh]

Good and informational video!!

[@pikukala]

nice video thanks for your efforts

[@dadibaric4367]

hey, can you help me? whats the rule of transistor in wireless charging/power trasmission? thanks

[@bilal16606]

Is it possible to make a transformerless variable power supply with these schematics ? i wish to make one because the high amp output variable power supplies is quite expensive for me.

[@unqtrunqmegawatt1449]

I'm trying to understand the voltage bust part of the circuit, the arduino pin never seems to make use of the burst? nor does it appear in the triac side of the circuit.

[@unqtrunqmegawatt1449]

+GreatScott! Like u define the zero on pin 2 but never use it?

[@unqtrunqmegawatt1449]

After some time reverse engineering, I finally found the issue was with an Arduino Leanardo, the attach interput is "1" to reference pin 2.... After finally reading up on the attach interput it became apparent why my angle function wasnt being called. Great video circuit performs as expected :)

[@vivekchoudhary3331]

sir can you please upload a video on piezoelectric transducer

[@iblesbosuok]

how to make dimmer with two thyristors, a diac, a capacitor, a resistor and a potensiometer? should I use two pulse transformers? cheers from Indonesia

[@adamcowlam5527]

I now just read on the data sheet that the IC can be used in switch mode power supply feedback, could this be related to your certain application? Thanks

[@ayuclack]

Hey I was trying a similar Circuit for making AC dimmer for 220V using BTA 12 TRIACs, the problem is when I use if for controlling fan speed it controls its speed but their is a humming noise. What could be the reason , do I need a snubber circuit

[@dhirajingale7381]

Your given program is not working, as zero crossing is not synchronized with the generation of pulses. You defined zero at pin 2 but not used anywhere in main program. Can you provide me original used program and help me ?

[@deltaray3]

THAT WOULD BE AWESOME!

[@ThePipton]

What sort of Triac could I use for a 16 volts AC motor? I can not find anything on google :/

[@deangreenhough3479]

Great video. Can you please clarify the Ac unit you were using and A SAFE voltage to experiment with, is it max 50v Ac. Also what is the safest way to move from DC TO AC work. This could be a great help to those of us that only work on DC. Maybe this could be a future project. Thank you

[@jyotiradityasingh9196]

1:50-1:57 he increases the resistance by increasing the leds and with resistance increasing falls the current the how does it increase the current

[@adamcowlam5527]

Hi, I don't understand what you are using the optocoupler for, I did here that the higher the voltage on the input, the more infra red light the LED emitted an therefore increasing the voltage on the output through a phototransistor but how does that then create a voltage burst at every zero point of every half wave? Thanks

[@ashish6633]

Really nice videos, keep up the good work. I have just one small question, by switching the triac what do we actually control. i.e. the AC voltage or the AC current. I mean to as if i monitor the AC Waveform across the load then will i get to see a clean sine wave?

[@coolaj86]

The Triac behaves like a full-bridge rectifier made from diodes. It is either fully on or fully off and does not limit voltage or current in the way that a Transistor (MOSFET) would. Instead, the current is controlled by waiting to activate the gate of the Triac until some number of milliseconds after the ac wave crosses the zero point. The full 60hz wave is 16.67ms wide, so each half is 8.33ms wide. He controls power delivery by adjusting the delay between 1 and 10ms before activating (closing) the Triac, which results in very crude waveforms which either begin partway into each half of the 60hz signal (1-8ms delay) or completely skips one half of the wave altogether, and a little into the next (10ms delay). As such using either a 4ms or 9ms delay is about the same in terms of getting half of the power, but using a 7ms delay would be far, far less. If you want a clean sine wave then you'd want to use a linear regulator (MOSFET) instead of a Triac. It would be less efficient for some uses and more efficient for others.

[@Messisan321]

Scott, your videos are amazing. But could you put the aproxx cost of the things you build? would be really nice

[@hollymedici2936]

Did you ever build an inverter using scr s if so I would like to see it

[@IbrahimInsomniac]

Im always watching your videos It helps me so much... I study in electrical engineering thank you so much

[@greatscottlab]

+Ibrahim Babaali You're welcome

[@908hanhouni]

First 😂 Awesome video as always.. Keep up the hard work 👍

[@TonyLehto]

Can such a cirquit effectively be used to slow down a router in a CNC? Or would a solid state relay & PWM slow down a Bosch Colt in my X-Carve? There's no speed control on the Colt.. I've tried mains light/LED dimmers but that didn't work..

[@Crux161]

I really love your videos :)