Using triacs for multiple input transformer

Thread Starter

b1u3sf4n09

Joined May 23, 2014
113
Hello all,

I want to provide multiple inputs into a transformer, and the first thing that jumped to mind was triacs. I would like to have qty 2: 120VAC, 60Hz power lines that feed into a transformer. Between each live and the transformer input winding, there would be a triac with the gate tied to its respective live input; current limiting resistor of 1000 ohms for each gate. There would also be LEDs (with appropiate limiting resistors) to indicate which triac was open. LEDs would be tied to neutral.

Components:
Triacs - Z0402MF 1AA2
Transformer - U002-2-010X

I put the components on a board and tested it out, but both triacs are opening when either live connection is made (e.g. when live #1 is switched on, I measure 120VAC across live #2 and neutral).

This circuit seems so simple, and yet I'm making no progress on it. Is there something plainly obvious that I'm missing, or is there a better way to go about this?
 
Last edited:

GopherT

Joined Nov 23, 2012
8,012
Could you draw out your plan (attempt) in a schematic? I think there is a misunderstanding of what a triac does and how they can be used.
 

Thread Starter

b1u3sf4n09

Joined May 23, 2014
113
I was neglecting quadrant III operation. Some time in the lab answered my question. I apologize for not updating sooner.
 
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