How to build NE555 Basic Monostable

Circuit diagram

Notes

Here the popular 555 timing IC, is wired as a monostable. The timing period is precise and equivalent to:-

1.1 x R1 x C1

With component values shown this works out at approximately 1.1msec.The output duration is independant of the input trigger pulse, and the output from the 555 is buffered and can directly interface to CMOS or TTL IC's, providing that the supply voltages match that of the logic family.

The timing diagram above shows the output pulse duration, the trigger input and the output at the discharge terminal of the IC.

circuit from http://www.zen22142.zen.co.uk/