The NE556 dual monolithic timing circuit is a highly stable controller capable of producing accurate time delays or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For a stable operation as an oscillator, the free running fre- quency and the duty cycle are both accurately controlled with two external resistors and one ca- pacitor. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200mA.