What is a Triac?

[Jeffrey681]

I have been looking at the components in a controller just to get a better understanding of how things work, I am looking at the Triac, an interesting componant, I am putting 240v into the controller and feeding out via the Triacs (16) to my LED strings, am I right in thinking the Triac detects the power requirement for each individual channel ? Or have I got this completely wrong.. please be gentle my learning process continues.

Jeff

[travis p]

think of it as a gate open current passes when closed no current passes

  load
data + ground
power source

Edited January 20, 2013 by LORAdmin
Trying to get the text to show as intended.

[travis p]

thanks to bb the text above is scrambled place the word load over the + sign

[plasmadrive]

There are a lot of web pages explaining how they work if you search them out.. The problem is that most of those pages assume you have a certain level of electronic understanding and they get far more technical then you want.... But I would take a bit of time and search it out anyway.. There is bound to be an explanation that fits the level you want to know.

With that said.. The Gate analogy is a good start. Once you trigger it (push the open button) and the "gate" opens, it stays open until nothing more (current) goes thru it... (That happens ever 1/2 cycle of the AC at zero volts...Kinda). even when you take the trigger away it will stay open until current is close to zero. You must again push the gate open button (trigger) at every 1/2 cycle of the AC to make it work again and again.

Triacs are NOT self regulating.. they will allow as much current thru them as you load them up with until at some point you will have broken the gate and it will either fall off the hinges and allow everything thru (a short) or the gate will fly apart in a puff of smoke and a crack of explosion (letting out the secret smoke) This is why you fuse them and also limit the load you allow them to switch. Every once in awhile the gate gets stuck partly open and allows too much to go thru. Time to replace the gate....

Does that help any?

[LOR Staff]

From a functional standpoint, think of a Triac as nothing more than a dimmer switch that can be controlled electronically by another source.

By telling the switch when to turn on and either knowing when it will shut off [something called the 'zero cross]', or telling it explicitly to turn off [if using something called 'pulse width modulation'], we can control the amount of apparent voltage on the switch. Since voltage and current are related, and in this case less voltage = less current = less electrons (those things that make lights glow) that =s dimmer lights.

The gate analogy is excellent, especially when it comes to understanding what happens when you break a triac. I'm going to steal that BTW .

[plasmadrive]

t purser started it.. it is his fault!

I stole his start.. you can surely steal my ending..

Edited January 19, 2013 by plasmadrive

[travis p]

im a simple man i just try to put things in simple terms when i can and i can t get long winded hunt and peck takes to long to type it all out

[Jeffrey681]

Thanks, very helpfull and yes you are right a lot of web material is a little out of reach for me, your explaination about them not being 'self regulating' is great, thats exactly what I was seeking to understand, thanks again, can you explain how they are regulated (limit the load they are allowed to switch) is this a process you go through when programming the controller?, I am only planning to drive LED strings.

Jeff

There are a lot of web pages explaining how they work if you search them out.. The problem is that most of those pages assume you have a certain level of electronic understanding and they get far more technical then you want.... But I would take a bit of time and search it out anyway.. There is bound to be an explanation that fits the level you want to know.

With that said.. The Gate analogy is a good start. Once you trigger it (push the open button) and the "gate" opens, it stays open until nothing more (current) goes thru it... (That happens ever 1/2 cycle of the AC at zero volts...Kinda). even when you take the trigger away it will stay open until current is close to zero. You must again push the gate open button (trigger) at every 1/2 cycle of the AC to make it work again and again.

Triacs are NOT self regulating.. they will allow as much current thru them as you load them up with until at some point you will have broken the gate and it will either fall off the hinges and allow everything thru (a short) or the gate will fly apart in a puff of smoke and a crack of explosion (letting out the secret smoke) This is why you fuse them and also limit the load you allow them to switch. Every once in awhile the gate gets stuck partly open and allows too much to go thru. Time to replace the gate....

Does that help any?

[plasmadrive]

Thanks, very helpfull and yes you are right a lot of web material is a little out of reach for me, your explaination about them not being 'self regulating' is great, thats exactly what I was seeking to understand, thanks again, can you explain how they are regulated (limit the load they are allowed to switch) is this a process you go through when programming the controller?, I am only planning to drive LED string

Jeff,

As I said, triacs are NOT regulating or regulated.. as in they will not limit the load they are allowed to switch. . So.. I am assuming you are asking how do they dim..

As not to get too deep in this technically (I tend to ramble if you haven't noticed)....

The electronics that tell the triac to turn on, tell it to wait to turn on until later in the half cycle of the AC sine wave. The lights will be off for some time period and then on for some time period. The result is an output average value that is something less then full on and the lights will be dimmer. So the more OFF time vs. ON time equals dimmer lights. Just FYI.. this cycle of off vs on repeats about every .0083 seconds for 60Hz power.

When you program your show with LOR or other light control software, the software tells the hardware how bright it wants the lights and the hardware does it. (Kinda). There is a lot more to it, but not something you really have control over at board level. That is what we pay LOR to do!

Did that answer your question or was I in the wrong pasture with my gate opener?

[Jeffrey681]

Jeff,

As I said, triacs are NOT regulating or regulated.. as in they will not limit the load they are allowed to switch. . So.. I am assuming you are asking how do they dim..

As not to get too deep in this technically (I tend to ramble if you haven't noticed)....

The electronics that tell the triac to turn on, tell it to wait to turn on until later in the half cycle of the AC sine wave. The lights will be off for some time period and then on for some time period. The result is an output average value that is something less then full on and the lights will be dimmer. So the more OFF time vs. ON time equals dimmer lights. Just FYI.. this cycle of off vs on repeats about every .0083 seconds for 60Hz power.

When you program your show with LOR or other light control software, the software tells the hardware how bright it wants the lights and the hardware does it. (Kinda). There is a lot more to it, but not something you really have control over at board level. That is what we pay LOR to do!

Did that answer your question or was I in the wrong pasture with my gate opener?

Again very helpfull, thanks, I guess the thing I am having a problem understanding is with 240v supply going into the controller, and potentially delivering 240v through each channel out to the lights, how does this get stepped down to diliver the correct voltage for the LEDs, am I looking at installing 240v to 12/24volt transformers? sorry if this is a little basic but anything that gives me a better understanding is very helpfull

Jeff

[travis p]

thanks admin for correcting my post above thats what i had in mind Jeffery as long as it takes 240 volts to power the power supplies that is where the power is stepped down not the controller now the dining is out of my comfort range those more knowledgeable than i will have to answer that one

Edited January 20, 2013 by t purser

[plasmadrive]

Again very helpfull, thanks, I guess the thing I am having a problem understanding is with 240v supply going into the controller, and potentially delivering 240v through each channel out to the lights, how does this get stepped down to diliver the correct voltage for the LEDs, am I looking at installing 240v to 12/24volt transformers? sorry if this is a little basic but anything that gives me a better understanding is very helpfull

Jeff

Ya know.. I never even noticed you are in the UK until you asked this question.. sorry...

There are a few things unclear at this point. First off, If you are using LED strings, are you using 240v strings? if you are using 240 stings, the controller works pretty much the same way, just higher voltage.

If not what are you using? I can better answer your questions if I have more info. For low voltage stings we have to start at a different place.. Let me know what you have or are planning to use.

Edited January 20, 2013 by plasmadrive

[Jeffrey681]

Ya know.. I never even noticed you are in the UK until you asked this question.. sorry...

There are a few things unclear at this point. First off, If you are using LED strings, are you using 240v strings? if you are using 240 stings, the controller works pretty much the same way, just higher voltage.

If not what are you using? I can better answer your questions if I have more info. For low voltage stings we have to start at a different place.. Let me know what you have or are planning to use.

Thanks again and apologies for asking such basic questions, yes I plan to use 240v strings, but am I right in thinking that each one of the 16 power out leads on the controller will need to have an ‘inline’ 240v to 12/24v vdc transformer to drive the LEDs ?

Most LEDs sold here in the UK have the transformer built into the power supply that feeds a multi function unit, not convinced this is the way forward for me, I think I need to source ‘static LEDs’ for my display. LEDs from the US are far less expensive but are only 110v.

The journey continues ...........

Jeff

[plasmadrive]

Hi Jeff,

Your situation is interesting to me.. so ask away.. let me pose some questions and perhaps some ideas.

• You do not want to use the kind of lights that have a controller on them. You want to use what you are calling "static lights". The LOR controllers are what you want to use to control lights..
  
• As for the 120 volt part.. you could use a single 240/120 transformer to feed the controller and the lights. Since you would be using LEDs, the required over all size of such a transformer would not be too big. (I can help you figure out the size when you figure out what type and how many lights you need).
  
• If you use light strings, make sure you get full wave type. Your power is at 50hz and there would be a lot of flicker with half wave. As it is you are right on the edge of visible flicker, but should be ok.
  

You may want to consider using low voltage DC LED strings or "Dumb pixel" strings. If you do that you can use a 240vac to 12vdc power supply and the LOR DC controllers. You can buy cheaper controllers but I am guessing that plug and play is going to be important to you. As well, the LOR DC controllers are PWM which is the best way to run LEDs for dimming.

If you want to get into full blown pixel control, (controlling every single LED and color individually) then that is another subject. Best to figure out what you want to accomplish over all and then decide how you need to get there.

Keep the questions coming.. Actually maybe start another thread with what we started here..

[Jeffrey681]

Hi Jeff,

Your situation is interesting to me.. so ask away.. let me pose some questions and perhaps some ideas.

• You do not want to use the kind of lights that have a controller on them. You want to use what you are calling "static lights". The LOR controllers are what you want to use to control lights..
  
• As for the 120 volt part.. you could use a single 240/120 transformer to feed the controller and the lights. Since you would be using LEDs, the required over all size of such a transformer would not be too big. (I can help you figure out the size when you figure out what type and how many lights you need).
  
• If you use light strings, make sure you get full wave type. Your power is at 50hz and there would be a lot of flicker with half wave. As it is you are right on the edge of visible flicker, but should be ok.
  

You may want to consider using low voltage DC LED strings or "Dumb pixel" strings. If you do that you can use a 240vac to 12vdc power supply and the LOR DC controllers. You can buy cheaper controllers but I am guessing that plug and play is going to be important to you. As well, the LOR DC controllers are PWM which is the best way to run LEDs for dimming.

If you want to get into full blown pixel control, (controlling every single LED and color individually) then that is another subject. Best to figure out what you want to accomplish over all and then decide how you need to get there.

Keep the questions coming.. Actually maybe start another thread with what we started here..

Sorry forgot to mention the following kit has been ordered from LOR and should arrive soon, this may offer a little clarity, or I may have jumped in to early buying kit.

SPK-ST Generic Starter SPK-ST 1 Cable = 10ft Cat5 Cable

Package Connector = USB - USB485

Feature Level = Basic

Software = Download Only

16 Channel Kit - Deluxe CTB16KDWHS x 2 (high-power heat sinks) 240v

[plasmadrive]

I think the CTB16KDWHS can be configured for 120v or 240v.. If that is the case, you should be ok..

[Ken Benedict]

It kinda sounds like you want to run 12 volt DC LED strips or strings in your display. And you were thinking about a step-down transformer for each string.

If that's correct, Plasmadrive suggested a great approach of using the LOR DC controller and a seperate power supply to accomplish this.

Running multiple strips will be cheaper and easier this way.

Is this the direction you're going?

[plasmadrive]

Hey Ken,

Looks like he already ordered two of the CB16 kits..

Craig