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Relay Snubber Design Help Please

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mortuzahasan

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Hi All,
I am designing a microcontroller based home automation which will derive 10-16 12V 5A relay through RF transceivers. i am using ULN2804 to drive the relays. in the contact side the relay would drive loads like ceiling Fans, lights and other home appliences for long periods. what sort of EMI protection should i have on the circuit. As ULN2804 has built in clamp diode, in was thinking to put a 220uF cap across the relay coil. what sort of snubber on the load side shall i connect? what would be the R-C value for the snubber and how to connect them (e.g parallel with switch). please help me.

*** By mistake posted in Microcontroller Forum in previous. Apology for any inconvenience
 

can you please share the schematic diagram for your circuit, with approx inductance value for your load.
 

Thanks for your reply.
i have not prepared the schematic yet, but the consideration is the relay will drive ceiling fan, light bulb etc. as per my understanding, ceiling fan is 90W in 220V A.C supply. all the appliances will draw from 220V supply. the assumption is to run 3-5A per relay and at least 10 relay will be operating at any time. thanks and waiting for your advise.
 

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