Switching AC circuit by relay.

[tapu]

Dear All,
I am Using relay of 12v dc for swithing AC mains to controll appliace like bulb by microcontroller 89c52.Here is my Relay-circuit.
**broken link removed**

Here mains supply comes from J4 connector.bulb(not shown in circuit) is connected to J2.When relay energised then bulb will be ON.The project have been succeeded.but one doubt in mind , is it dangerous to touch hand to J2 connector as when relay is not energised but AC input is given??Becouse one pin of J4 is shorted to pin of J2.I can't check it becouse it is 230v ac. Please reply.

 

[red_alert]

I can't see the attachment but if you're using a two-pole relay (to interrupt both mains live and neutral) then you could touch the bulb connector.

 

[tapu]

if above attached circuit can't open then check this circuit.

 

[red_alert]

As you can see, pin1 of J2 has a direct connection to J4 so you can't avoid mains voltage by hand touch. You could minimize the effect by connecting the mains neutral to pin2 of J4 (but it could be dangerous, too, if you don't have an earth connection and a differential circuit breaker).

For safety, use a dual pole relay.

 

[tapu]

dear All,
above problom has been solved.one problom here I want to control electric bell by alarm clock circuit.(bell rings for 2 second).as signal comes from controller the bell rings & stop.but after that time will not change.please reply.
(here I am using decoders & buffers for each digit)

 

[tapu]

here i am using two regulators 7805 for controller circuit& 7812 for relay circuit and same ground terminal for both relay circuit and microcontrller with a single transformer output.may it be a problom?