How to switch A.C. load without relay with arduino..??

I am making a push button switch board for switching ON or OFF A.C. load.

Please tell which way it be reliable, using RELAYS, TRAICS or SCR...?? Personally I do not want to use relays, so if I use a TRIAC, then how should I connect it to arduino . Can I connect the GATE of the TRIAC directly to arduino ar I should use a MOC3011 optoisolator..??

Use an SSR as that is a triac with built in opto isolator and zero crossing detector.

Otherwise use a triac with either a built in opto isolator on the gate or a seprate one. With an SCR you only get half the power.

depends on how much you want to use it (switching on/off)

if it's a lot of switching on and off. avoid relays... a solid state relay would be a good alternative for a lot of switching...

out of curiosity, what is you're doing?

For switching light loads, you can use an opto triac such as http://www.farnell.com/datasheets/1244301.pdf. For higher loads, use an SSR - it's easier than making one yourself from a triac.

cjdelphi: depends on how much you want to use it (switching on/off)

if it's a lot of switching on and off. avoid relays... a solid state relay would be a good alternative for a lot of switching...

out of curiosity, what is you're doing?

I am converting my bedroom electrical switch board to digital. That is , instead of the piano switch I will be using tactile push buttons to switch LIGHTS, FAN and etc. Later in few days I will add a IR sensor and a remote to control them with an IR remote..

Opto triacs should be OK for switching lights and fans, assuming a 230V mains and no more than 200W of lighting per circuit.

Another thing is that please tell me some SSR which are common and are mostly available.. load will be 500W maximum

Assuming about 230VAC mains, 500W is a little over 2A. This one http://uk.farnell.com/sharp/s201s06f/relay-solid-state/dp/1618473 looks the most economical. See also http://in.element14.com/jsp/search/browse.jsp?N=204034+110138169+110170154&Ns=P_PRICE_FARNELL_IN%7C0&locale=en_IN&appliedparametrics=true&getResults=true&suppressRedirect=true&isRedirect=&originalQueryURL=/jsp/search/browse.jsp%3FN%3D204034%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_IN%26divisionLocale%3Den_IN%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D204034 for supplies in India.

please tell me some SSR which are common and are mostly available

The block-type SSR is easy to use and widely available.

You can control it directly from an Arduino pin. It has optical isolation built-in It can control lots of power

Examples: http://goo.gl/oe6a0

DISCLAIMER: Mentioned stuff from my own shop...