Difference between revisions of "555 Timer"
From Mech
Jump to navigationJump to search| Line 1: | Line 1: | ||
__TOC__ |
__TOC__ |
||
Pin layout for the LM555 timer: [[Image:555_symbol.gif]] |
Pin layout for the LM555 timer: [[Image:555_symbol.gif|400 px]] |
||
[http://www.national.com/ds/LM/LM555.pdf Datasheet for the LM555] |
[http://www.national.com/ds/LM/LM555.pdf Datasheet for the LM555] |
||
Inside the 555 timer is a voltage divider the divides +V<sub>CC</sub> into thirds. A voltage comparator compares the '''trigger''' input (pin 2) with 1/3 V<sub>CC</sub>, and another comparator compares the '''threshold''' (pin 6) with 2/3 V<sub>CC</sub>. The point at 2/3 V<sub>CC</sub> on the voltage divider is connected to the '''control voltage'''. |
|||
==Monostable and Astable mode== |
==Monostable and Astable mode== |
||
The 555 family of timer chips can be used in either '''monostable'' mode or '''astable''' mode. |
The 555 family of timer chips can be used in either '''monostable'' mode or '''astable''' mode. |
||
Revision as of 12:20, 3 July 2006
Pin layout for the LM555 timer: 400 px
Inside the 555 timer is a voltage divider the divides +VCC into thirds. A voltage comparator compares the trigger input (pin 2) with 1/3 VCC, and another comparator compares the threshold (pin 6) with 2/3 VCC. The point at 2/3 VCC on the voltage divider is connected to the control voltage.
Monostable and Astable mode
The 555 family of timer chips can be used in either monostable mode or astable' mode.
