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I'm really new to building electronics, so please forgive my ignorance.

I'm looking to be able to supply 24vac (~.5A) to one of 16 outputs using 4 3.3v, 50mA inputs. (Edited) The 4 3.3v inputs are from a microcontroller, that I want to use to select one of the 16 outputs (traditional multiplexer problem). I was hoping that there is some sort of multiplexer that I could hook up down stream from a relay in order to supply the power with few components. So I'm looking to find/build a multiplexer circuit that takes 4 on/off low power inputs and the "data" line is 24vac. My alternative is using a multiplexer and relays/TRIACs.

I've seen posts where people use TRIACs/relays directly for this, or use a multiplexer to run a number of TRIACs and relays. I also saw someone talking about using MOSFETs... I'd rather use less components if possible.

EDIT:

After doing some more research, I think I need a 1:16 analog switch. I think I need something with an optocoupler or something that will protect my circuit board from the 24vac that will be switched. I looked at the DG406DJZ and NTE4051B... but I really can't tell if they meet my needs.

EDIT:

Well, I ended up buying this: DG406DJ-E3 : http://html.alldatasheet.com/html-pdf/249648/VISHAY/DG406DJ-E3/219/1/DG406DJ-E3.html. The 5 data lines will be 3.3V, 50mA. The analog connect will be 24vac at .5A or so, to be switched to one of 16 outputs. I think this is an isolated circuit so I shouldn't have to worry about ruining my board in cases of failure. Is this really going to work like I think it will? Will my microcontroller be protected with this setup? Is there something else I should be considering? This seems like a simple design based on some of the others I have seen.

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A door bell transformer should fit that very well. Do you need to do it the other way?

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  • \$\begingroup\$ Thanks for the answer, I think I probably should be more specific in my question. \$\endgroup\$ – Devin Sep 20 '12 at 21:45

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