Ring oscillator is useful for digital circuits. It is constructed with odd number of inverters. Propagation delay increases if the number of inverters increases. Therefore, oscillation period increases. By using passive elements at the output of each inverter, the oscillation period can be also increased. Passive elements configured as high pass filter .
(Series R / Shunt C) or (Series L / Shunt C)
Leftmost 2 stages are used as buffer. They also regulates the signal. Enjoy!
