protected power supply for microcontroller circuit.

[tapu]

Dear All,
I have dsigned microcontroller based alarm clock.But I connected AC mains directly to Transformer's primary.Here I use 230v electric bell as a alarm(according to it's application).By using 5v dc relay.circuit works when bell is not connected.when I connect bell,at particular alarm time bell rings but clock stops.Is this problom is due to absense of protetion circuit in power supply?if yes then how to design protection circuit?

 

[srizbf]

Dear All,
I have dsigned microcontroller based alarm clock.But I connected AC mains directly to Transformer's primary.Here I use 230v electric bell as a alarm(according to it's application).By using 5v dc relay.circuit works when bell is not connected.when I connect bell,at particular alarm time bell rings but clock stops.Is this problom is due to absense of protetion circuit in power supply?if yes then how to design protection circuit?

the source of this type of problems can be judged only when you give your exact circuit.

whether a protection is necessary or a filter will solve , depends on your design and connection.

is it the same one 'alarm problem' posted in some other thread ?

 

[chuckey]

Bells produce a lot of sparking at their contacts, you need a snubbing circuit across the bell contacts and make sure that you have good Vcc decoupling as well.
Frank