I'd expect the BC547 to get damaged due to the base being over-driven. There should be a current limiting resistor between it's base and pin 3 of the 555.
Why do you need the BC547, Rb and Rbb anyway? Can't you drive the MOSFET directly from pin 3 of the 555?
Also, what is the purpose of R1? It doesn't seem to have any useful purpose.
I'd expect the BC547 to get damaged due to the base being over-driven. There should be a current limiting resistor between it's base and pin 3 of the 555.
Why do you need the BC547, Rb and Rbb anyway? Can't you drive the MOSFET directly from pin 3 of the 555?
Also, what is the purpose of R1? It doesn't seem to have any useful purpose.
I think that the timer IC has not been properly configured in astable mode.Check the datasheet.Try either disconnecting the pin 7 or connect the pin 7 properly to the node in the schematic.