This is a very simple LED flasher circuit using LM3909 IC. LM3909 is a great LED flasher IC operated only on 1.5 volt DC and gives a bright-high current LED pulse and work on wide temperature range. This IC has a very low current consumption due to which a 1.5 volt (C) size cell or 1.5 volt AA
size alkaline battery will last more than a year on continuous operation.
Although LM3909 ICs are not manufactured any more but some electronic shops have stock of it and it is still available in some parts of the world and also online on some websites.