NE556 Dual Timer IC
The NE556 dual monolithic timing circuit is a highly stable controller capable of producing precise time delays or oscillations. Operating as a time delay, the time is accurately controlled by one external RC (resistor/capacitor)network.
For a stable operation as an oscillator, the free running frequency and theduty cycle are both set with two external resistors and one capacitor.
The circuits may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200 mA.