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This video features a circuit that triggers a triac using a DC: https://www.youtube.com/watch?v=ZXXup79B6Gc

I would like to make a little modification on it it. The video says that I have to connect the "Neutral" of mains to "Negative" of the DC battery, this is a bad restriction for me because I want to connect AC mains at any direction (position), no matter where the hot(live) line is. Any Ideas? Can optoTriac do it?

enter image description here

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Two possibilities:

  1. Supplying your device from Mains: use a bridge rectifier and any circuitry you see fit (this is a question too broad to be answered here) to get your supply voltage. With that voltage you can control your triac.
  2. Supplying from battery/external DC source: Then you have two voltage sources that mustn't be connected directly. In this case you need an optotriac. Look at page 4 for reference: MOC3020 opto triac

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ My load needs AC Supply so I don't think the first possibility is suitable. The second possibility is very useful, Is it ok to use a separate optoisolator with a triac instead of an optotriac? \$\endgroup\$ – Michael George Oct 13 '15 at 12:59
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    \$\begingroup\$ Maybe I was not totally clear what I was meaning. In the first solution you of course switch an AC Load. You only generate your own DC voltage for controlling the Triac through some additional circuitry. But if you already have some other voltage (for example a battery), then yes, solution 2 is better for you. \$\endgroup\$ – jwsc Oct 13 '15 at 13:10
  • \$\begingroup\$ I don't see the point to one triac that turns on another. You've re-invented a solid state relay, but more complicated. \$\endgroup\$ – Olin Lathrop Oct 13 '15 at 14:39
  • \$\begingroup\$ @olin no. With a triac i can dim a load through phase cut and a relay needs more current. That opto triac works with 10mA. A relay needs at least 30. If only ON/OFF switching is required then yes. A relay would be easier. But the OP specifically asked for triac. \$\endgroup\$ – jwsc Oct 13 '15 at 15:17
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It's not clear what you are really asking, but possibly what you want is a solid state relay. Some of those are optically-triggered triacs. You drive the internal LED, and it turns on the triac.

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