AC basic circuit help

Using Arduino General Electronics
1

Hi, I only work with DC circuit but now I need work with 220 AC circuit.

I need to use a relay for On-Off home light.

This is good?

I need to use some fuse?

2

Nothing wrong appart from three wires from the relay to the arduino, you only need two here and a diode across the relay and a transistor to drive the relay.

3

Keep in mind that your rendition would allow the arduino to turn on the light if off but would not be able to turn off the light if the shown manual light switch is in the on position.

Lefty

4

Three wires to the relay might be valid - if its a latching relay (which is a fair
choice to make).

5

MarkT:
Three wires to the relay might be valid - if its a latching relay (which is a fair
choice to make).

I bet you it is not. :slight_smile:
£10 to the Philippines hurricane relief fund.

6

I am am using this type relay:

for that reason I am using 3 wires.

But I have a doubt when viewing the home switch. I thought that a AC swich only have a 2 wires but mine have 3 and I don´t know performance.

you could help me to understand the performance?

My switch:

Thanks.

7

I am am using this type relay:

That is not a relay, it is a module that contains a relay and other stuff as well.

you could help me to understand the performance?

Odd words, I think you mean the function.

Remove the wires from the switch and test with a multimeter set to resistance to be sure, but it looks like you have a single pole change over switch. The common wire, the one at the bottom will be connected to the left or the right depending on which way the switch is set. These are used in wiring where there are two switches say one at the top and the other at the bottom of the stairs. Changing either switch will change the state of the light.

8

Since you have a three way switch (as we would call it here in the USA, but in the UK apparently they call it a "change over switch") now you must have a second three way switch in your circuit. If you want to add a Arduino controlled relay to your circuit and still be able to use the existing switches as well then you would need a DPDT (double pole, double throw) relay; in the USA we'd refer to this type of wiring as a "four way" switch.

I'd suggest you jump on Google and find a few diagrams of how to wire these switches. An image search for "four way switch" yields many results for me here in the USA but YMMV on your side of the planet. And, as always, it'd be best to consult someone with experience in home wiring to ensure you do it right and don't burn your house down.

9