555 timer

555 timer is a very simple IC, but it is very powerful to create many useful application and small project for student or DIV hobbyist.

There are few type of basic application that can be done by the 555 timer.

• Astable - producing a square wave
• Monostable - producing a single pulse when triggered
• Bistable - a simple memory which can be set and reset
• Buffer - an inverting buffer (Schmitt trigger)

Reference Site:

1.  http://www.kpsec.freeuk.com/555timer.htm
2.  http://home.cogeco.ca/~rpaisley4/LM555.html