NE555DR SOIC-8 SMD Timer IC

These devices are precision timing circuits that can produce accurate time delays or oscillations. In time-delay or monostable mode of operation, the time interval is controlled by a single network of external resistors and capacitors. In a-stable operating mode, frequency and duty cycle can be controlled independently by two external resistors and a single external capacitor.

 

Threshold and trigger levels are normally set respectively by VCC It is two-thirds and one-third. These levels can be changed using the control voltage terminal. When the trigger input drops below the trigger level, the flip-flop is set and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip flop is reset and the output is low.