Fuse blown buzzer and circuit over current protection circuit

Thread Starter


Joined Jul 5, 2019
I am designing a prototype for a fuse blow buzzer and overcurrent protection circuit for 18VAC tranformer. Transformer has 2Amp fuse on the line. I am using AC optocoupler SFH628A-3 to sense current from the line and trigger an SCR that will operate relay. The buzzer is attached to NO of the 24VDC relay. My I need help in
1: I am unable to get short circuit conditions and use of proper resistors to limit the current.
2: I need guidance about how can i operate relay based on the current sensed from optocoupler and implement protection.
Your guidance will be highly appreciated.

I am new in circuit design and helping me in this will be great help.