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Topic: varying high voltage (Read 1 time) previous topic - next topic


hey guys...I live in South Africa so we use 220V-240V AC. Im looking for ways to to interface the arduino with such power sources for things like home lighting. Basic on and off is fine but my biggest problem and focus is accomplishing a dimming function. what are my options as far as thats concerned?

Thanks in advance:)


What would you like to dim ?
Lights ? What kind of lights ?


i currently have  2W led down-lights but i will replace them accordingly with dim capable ones.


i was also thinking of controlling the speed of my high velocity fan


2W led down-lights

They are fairly (read: very) difficult to dim.

If I would you, I would start with regular incandescent light bulbs: you can dim those things easily with a bridge rectifier + mosfet, if you are OK with floating the whole dimmer.


if by floating you mean putting it in the ceiling then yes thats fine!! im not completely clued up with electrical components so which mosfet type should i look for?


im not completely clued up with electrical components

In that case, don't work on mains.

Try something simpler / safer.


Feb 02, 2013, 12:08 am Last Edit: Feb 02, 2013, 12:12 am by lemming Reason: 1
Have a look at :


You will need to use incadescent lights for this circuit and do your homework. These are lethal  voltages.


i acknowledge the risk involved but i meant specifically the mosfet needed. applying it is no problem...in addition i found this just now online:
although the site disclaims that users said it was unsafe. is this true or just for legal purposes?


i found this just now online:

That's the basic structure.

is this true or just for legal purposes?

It is true.


Feb 02, 2013, 12:14 am Last Edit: Feb 02, 2013, 12:17 am by lemming Reason: 1
No. Use an optoisolator as used in the thread that I posted.  If there is a problem with the circuit, you are less likely to have 240VAC feeding back into the user.


Okay...thank you so much for the help...i shall start there:)

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