I have done this circuit and it keeps the LEDs on permently (i changed the buzzer to be in parallel with the LED's aswell) (i need them off for xx amount of time and then on for 1 second and then off agian.
The 100E (100R) resisitor does nothing as the 3v source barely lights these LED's on its own so i guess i will need a larger power source
EDIT: Basically i want a camera flash (would need to be 3 or 4 flash tubes as i need 360 degree coverage) but timed for 5 - 10 seconds (variable with the variable resistor)