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Topic: Photo-triac low current ac output; is secondary triac needed (Read 1 time) previous topic - next topic

nitrof

Hi.

I want to use a photo triac to control ac 24V relay. So I expect maximum 150mA load.

I didn't found any example if it is possible to put a small load on photo triac directly on it without a secondary triac. I want to know if it is even possible and if yes, some cue how to do it.

Thank.

DVDdoug

Have you go a link to the photo-TRIAC datasheet?

And...  If the relay has a 24VAC coil, most relays with AC rated coils will also work from DC.

Grumpy_Mike

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I want to know if it is even possible
Yes if your opto triac can take the current.

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d if yes, some cue how to do it.
Like wiring up any other triac and load.

MarkT

Triacs/SCRs etc have both a maximum and a minimum current.  Make sure your load is greater
than the minimum and less than the maximum.

Simple.  Now post the device details (like the URL of the datasheet) and we can explain in more detail
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

nitrof

Good !


 First a tough of:
TLP266J

But I think It can sustain only 20mA regular rating... If I'm reading the data sheet right...

I tried to fing something else on digikey, but the price seem to very high... Maybe I search for part the wrong way... I tried on option: photo-triac, zero crossing, outpu 150mA min.

Grumpy_Mike

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But I think It can sustain only 20mA regular rating..
No that is the input current, the output is 1.2A continuous and 2A pulsed. Keep it down to 500mA and you will be fine.

nitrof

ho, yes I can see that now.

Good news! :P

another question, do I have to put a snubber with a zero crossing ??

Grumpy_Mike


nitrof

like a relay... in that case, how calculating it? I saw a tool on a site, it take rising time on parameter... how do I know that? Snubber-Design-Calculator.phtml

Grumpy_Mike

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how do I know that
It is a design input parameter, it is not something that you know beforehand.

try designing one with a rise time of 2mS.

MarkT

No that is the input current, the output is 1.2A continuous and 2A pulsed. Keep it down to 500mA and you will be fine.
70mA rms continuous, 1.2A is a surge rating.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

runaway_pancake

"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

nitrof

Thank Runaway. Seem what's I was lokking. It is sometime hard to find the perfect part at good price.

For the snubber I found this reference: how-to-calculate-resistor-and-capacitor-size-for-snubber-circuits

Seem to have the seem configuration except for the voltage, Is the 600V rating of vo2223a I have to use?

In that case, 1.5k resistor and 40uF cap will fit as snubber ?

nitrof

And. Arduino due pin current is 15mA max and max trigger is 10mA, should I add transistors if I use 10 of them?

runaway_pancake

"Is the 600V rating of vo2223a I have to use? 
1.5k resistor and 40uF cap will fit as snubber "

The rating isn't relevant for snubber circuit calculations, your line voltage is.
Why agonize over such a thing?  0.1uF, 100ohms

"Arduino due pin current is 15mA max and max trigger is 10mA, should I add transistors if I use 10 of them?"
Yes, but then you ought to use an actual power triac (or an SSR). 
Agree?
"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

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