Oscillator video series: Oscillators and oscillator principles

In episode one of this multipart series, David Meaney covers the basics of oscillators and oscillator principles. During the video, you will learn what an oscillator is, discover a variety of oscillator applications and what resonators are associated with them to build a functioning oscillator. To learn more about oscillators design basics, visit our channel for our next video on oscillator start-up time and reactance in an oscillator circuit!

What is an Oscillator?

An oscillator is an electronic circuit that generates a repetitive signal. This signal can be in many forms depending on the application. Some applications require a basic clock to maintain operational intervals for processes. Other applications require a clock with very clean waveform and tight stability to produce high quality communications and data transfers.

Oscillators can have several different types of resonators associated with them. The most prolific and best performing of these is quartz. You may also find oscillators that use ceramic, SAW or MEMS based resonators to be the starting point for the operational frequency. They use mechanical vibration or tuned cavities to generate the clock signal. In the case of the quartz-based oscillator, the composition of the quartz material, and the angles that the crystals are cut make this type of oscillator very precise and stable over a wide temperature range. The process for making oscillator grade crystal blanks is time consuming with many steps to ensure a consistent high-quality product, but they offer vastly superior stability over RC oscillators.

The principle behind the oscillator circuit is a stable steady state output signal. One way to accomplish this is by using a positive feedback loop. Here a portion of the output voltage is fed back to the input with no net phase shift, this feedback reinforces the output signal. The signal is then amplified and looped back again causing the output signal to grow. The gain in the feedback loop needs to be controlled to unity gain, otherwise, the signal will be clipped and distorted.

Click here to read more about oscillator circuits.