The circuit shown in the figure uses 2 of the 4 NAND gates of a 4011 and is designed to produce short duration pulses. The pulse duration is given by the diode and the resistor in series which can be changed as needed. The frequency of the oscillator is given by capacitor C and the 100k resistor. The frequency can be modified by changing the capacitor value. The relationship between the two resistors gives us an approximation between the duration and the pulse interval. The maximum recommended operating frequency for this oscillator is around 1 MHz. The minimum frequency depends only on the presence of leaks in the capacitor.
