Using Triac MOC3052 for ac load on/off

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1. Have to turn on or off, ac load using micro-controller. Microcontroller is +5V powered. 

AC load is resisitive wire of 780ohms for heating wire purpose.

 

2. using MOC3052, I am sending high & low on its anode, but output load dont get on/off.

 

3. I am not using any zero cross here, I check when measured temperature is below setpoint just send +5V on MOC3052's anode & keep high until temperature is higher then setpoint then 0V on MOC3052's anode.

 

Is it due to this, that MOC3052 dont get turn on or off, as I am not using zero cross?

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ckt

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I’d suggest you have a wiring error. What do you mean by no zero cross? I would suggest that for your application that a zero cross switching device be used, but this won’t make a difference between your circuit working or not working.
I’d be using a beefier triac than a bt131.the cold current of your heater might easily exceed the bt131 rating.

Last Edited: Mon. Dec 18, 2017 - 08:01 AM
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The LED resistor may be a bit large, try a 330 ohm and see if that helps.

 

Jim

 

Mission: Improving the readiness of hams world wide : flinthillsradioinc.com

Interests: Ham Radio, Solar power, futures & currency trading - whats yours?

 

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You might try to switch something simple like a led with youg MOC first.

Not only less messin' with high voltages during development, but it also eliminates other possible causes.

 

Note that the "A1" and "A2" pins on triac's are not interchangable.

Paul van der Hoeven.
Bunch of old projects with AVR's:
http://www.hoevendesign.com

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Vindy’s been away for awhile - maybe he’s figured out the problem already?

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...or started a post elsewhere...or many other places??

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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It makes things a lot easier to follow if you embed the image in the post - so that it can bee seen in context:

 

 

Instructions here: https://www.avrfreaks.net/comment...

 

 

But that's not (quite) how the datasheet suggests:

 

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Zero cross means nothing right now, only worry about full on.  Is your LED gnd  shared with your micro's gnd?  A common oversight, since  if not, there will be no led current.

Is you micro pin driving the led steady high?  If not, make it so for now.

Maybe you just managed to burn your triac out out (though it should support 800 ohms at line voltage), check the pinout carefully.

 

YOU NEED AT LEAST AROUND 15MA TO THE LED...plan accordingly.  You lose 1.5v in the led right off the bat.

5V: 230 ohm

3.3V: 120 ohm

.... about the limit for a micro I/O pin, but should be ok for tests.

When in the dark remember-the future looks brighter than ever.

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replaced ckt bt31 with bt136 & it is working

dont know why bt131 not working, everything same.

tried using new fresh bt131 also but didnt worked out.

 

bt131 & bt36 have different pinouts. i have take care of those.