Help needed with Wire Loop Game

Hello,

I wish to make the Wire Loop Game for a childrens' fun-n-fair. But I wish to add a simple SCR/circuit so that the buzzer sounds continuously instead of momentarily, once the loop touches the other wire.

Can someone please show me or direct me to a website with a simple SCR, which is easily available (in India since I'm from there) circuit that can do the job?

Any help greatly appreciated!

Thanks,
Deboo