NE555 Timer IC
The NE555 monolithic timing circuit is a highly stable controller capable of producing precise time delays or oscillation. In the time delay mode, the time is accurately controlled by one simple RC (resistor/capacitor) network. For a stable operation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external
resistors and one capacitor.
The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200 mA.