Relay interfacing with 18F4520

[paddy_p]

Hi,

Greetings of the day!!!!!

I have to interface relay with PIC 18F4520 micro controller.

Coil voltage of relay is 5V. So is it okay if I use common 5V supply for micro controller and relay coil or I need to use another supply for relay coil to get an isolation?

Please suggest.

Thanks
Paddy

 

[tpetar]

Use ceramic 100nF near +/- pins of uC, use flyback diode for relay :

**broken link removed**

 

[jayanth.devarayanadurga]

Why do you need isolation? What are you switching with relay?

 

[paddy_p]

Thank you very much tpetar and jayanth.devarayanadurga for your quick reply.

Actually I just want to provide potential free contacts and switching application is user dependent.

Is there any chances of damage if I am switching any high voltage load??

Please suggest.

 

[jayanth.devarayanadurga]

No there is no damage if relay is used. The load will be isolated from MCU board but you have to choose proper relay ratings for the load being switched.

 

[paddy_p]

Okay.

Thanks a lot for the advice!!!