What is the basic principle of timer 555 IC?

[my_books]

principle of timer

Timer 555 IC is the most used IC. It is an essential component of electronic circuits. But I am still unaware of it's basic principle. So help me to understsnd it.
Thanks

 

[Jack Luminous]

principle of ic 555

Have a look at this document (application notes from Phillips): www.doctronics.co.uk/pdf_files/555an.pdf

 

[l-o-s-t]

You can have a look at this :
www.interq.or.jp/japan/se-inoue/e_ckt4_2.htm

 

[safwatonline]

two comparator and a FF two nodes , one comparing with 2Vdd/3 and the other with Vdd/3 , and the two outputs are input to the FF , check the state machine for more details
check this link for a nice animated application:
http://www.williamson-labs.com/480_555.htm

 

[neils_arm_strong]

The timing i.e the ON period and OFF period depends on the resistor and capacitor values.Basically the comparators make it to work in astable or monostable state based on the connections.