1.5 V LED Flash Schematic

This simple flash you is very compact build in a brooch for example. I have the circuit extracted from a CD cover.

1.5 V LED Flash Circuit Schematic Diagram

The flash uses a 1.5 V supply, this is a penlight or use a button cell.

Capacitor C1 controls the flash frequency within certain limits. The declared value of C1 is the frequency about 1.3 Hz.
 
Parts List

C1 = 100 uF
D1 = Low current LED
IC1 = LM 3909