Relaxation Oscillator - Implementation

Implementation

Many electronic relaxation oscillators store energy in a capacitor and then dissipate that energy repeatedly to set up the oscillations. For example, the capacitor can be charged toward a positive power supply until it reaches a threshold voltage sufficiently close to the supply. At that instant, the capacitor can be quickly discharged (e.g., shorted). Alternatively, when the capacitor reaches each threshold, the charging source can be switched from the positive power supply to the negative power supply or vice versa. In all such capacitor-based relaxation oscillators, the period of the oscillations is set by the dissipation rate(s) of the capacitor. Implementations of these two types of relaxation oscillators are shown here, but relaxation oscillators need not be electronic in general. Any oscillator whose oscillations are driven by a system that almost always is dissipating energy may be called a relaxation oscillator.