Triacs Theory and Circuits

[@kennybassarath7168]

Finally, a video with British circuit symbols. A welcome respite, thumbs up!

[@LewisLoflin]

SCRs kzbin.info/www/bejne/b6O7oYutqqiCfZo www.bristolwatch.com/ele/lascr.htm Light Activated Silicon Controlled Rectifier (LASCR)

[@parasbhanot]

I am working on home automation project . This video solved my problem. Thank you.

[@sanityd1]

I'm still so lost when it comes to these.

[@hafizraseed]

Very good explanation of zeero crossiñg❤

[@LewisLoflin]

Thanks a lot 😊

[@hafizraseed]

My Dear may we can use capacitor/resister 105/400v=330k supply instead of p/secondary transformer before fullvawe bridg circuit in c/fan remote dimming.

[@LewisLoflin]

Yes you can. Some early LED light bulbs did just this.

[@tomz1067]

great video, can i use triac to power 110 v, 1,5 KW induction motor compressor from European 220? Any help would be appreciated.

[@ilyasshaikh172]

Could we use ceramic capacitor in dimmer circuit at gate 0.1 micro farad

[@LewisLoflin]

Don't see why.

[@raym9691]

Looking forward to seeing your next video on that!

[@francisquinn1857]

Hi Lewis,I’m very much a beginner,how does a triac actually control motor speed, I was thinking a variable resistor (potentiometer)would do this?

[@LewisLoflin]

A variable resistor can but waste power and get very hot. A triac is a switch and by proper switching one can control speed. Think of it this way, if you can flip a throw switch on-off fast enough the average speed can be obtained.

5:45 if 380VAC and MOC3052 ----> R1=?, R2=?, thanks so much!

[@LewisLoflin]

This came from a factory spec sheet. My guess is leaving them the same.

thanks! but if MOC3052 and 380VAC R1=R2=1000ohms D1=D2=1N4007 --------> LOAD always On

[@LewisLoflin]

Build a test circuit at 115V with a light bulb then confirm it's working. Put another lightbulb in series with the 1st and go to 240V, etc. Use low-watt bulbs in case something doesn't work right it will protect the parts.

I build a test circuit at 220V ( Thermistor 6kw-220V) with a light bulb then confirm it's working. Put another lightbulb in series with the 1st and go to 240V, etc. But Use hight-watt ( Thermistor 6kw-380V)----> LOAD always ON (10A). I thing change value of Resistor R1, R2, or 180ohms? Do you thing?

[@markarling891]

I have a triac controlling a dispenser motor in a washing machine, every once in a while I get a fault regarding that circuit. I ohm the motor out and that is fine, I was thinking that maybe the triac is starting to go bad and causing the motor to not run when it is suppose to or stays running longer than it should. Is this a possibility?

[@jamesmclaughlinprimitivele4587]

Mark Arling trial fail closed.

[@bergweg]

Hi, is there a way to detect the AC wave peaks without a micro-controller and/or without a diac+resistor combination?

[@LewisLoflin]

bergweg If you just want peak they're called sample and hold circuits often using op-amps.

[@bergweg]

Thanks. I was asking because I'm curious how you'd trigger a triac around the peak of the wave in a circuit with an inductive load such as a motor, in order to avoid high currents that would flow if you'd trigger at zero crossing.

[@saturn5tony]

At 4:53 you should have said Photo Diac not Triac. It is a Phototriac driver as some say like TI that your were driving at. It was very informative, Thx4sharing.

[@LewisLoflin]

The spec sheet says it's a photo triac and it is. I use a separate diac.

[@LewisLoflin]

Again read the spec sheet.

[@LewisLoflin]

I thought it was a diac at first.

[@saturn5tony]

Yea the same thing happened to me until I read that it is a photo triac driver in the TI and Motorola spec sheets for the 3021 and such. They do reference it as a silicon bilateral switch as well. Makes sense when you see it as a "bi" and "di"for that control or DRIVER as they say. So many terms. lol Im using one to power my variac design. Thank you though, all good fun and so interesting little devices.

[@LewisLoflin]

Thanks for the input.

[@tathagatabiswas9]

Thank you very much for the upload. Its incredibly helpful. I am using MOC3023 optocoupler and a two SCR connected back to back a switch a capacitive load connected to 240V AC. How will switch the SCR couple off? when MOC3023 is turned off (At the input side) the SCRs are still in conduction (latched!)

[@LewisLoflin]

Tathagata Biswas Thank you

[@LewisLoflin]

Tathagata Biswas If that is AC they should switch off. A triac is 2 back-to-back SCRs. I don't know what you mean by capacitive load. That could be a problem with phase.

[@tathagatabiswas9]

Lewis Loflin​​ Thanks for replying. Here Capacitive load means a bank of a capacitor to supply reactive power. Using 2 scr (not a single triac).. It's not switching off. However using a triac its working just fine. And yes its ac. 240V,50hz. 

[@nortenhardenberg1598]

You've said to trigger a TRIAC from MT2, why is it important? Explosion- the other way?

[@LewisLoflin]

No it just doesn't turn on the other way.

[@siddharthkilam]

very informative series, please keep it up

[@felixcat4346]

But Lewis, why don't my ceiling lights explode ever?

[@safm213]

4.7k rated??

[@LewisLoflin]

Sergio Maravilla 1/2 watt

[@jukees3658]

As always, great video, good info.

[@AltayBrusan]

thank you

[@alibehrouz9833]

nice job

[@sreekumarUSA]

Thanks.

[@kpkittu7]

thank u for the excellent understood many things abt triac

[@buddhikadharmasena7154]

thanks for you

[@samj1012]

good video thumbs up

[@kaisang5672]

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