Oscillators are a type of circuit that produces output without using an AC input signal. The repetitive discharges of signals are managed by oscillators. These signals are found in devices that have a continuous measured motion, like the pendulum of a Grandfather Clock. Computers also need oscillators, especially when performing computing tasks, which counts clock speed as an important feature. The clock speed’s frequency, which is expressed in gigahertz or megahertz, is set by oscillators.
There are two main types of oscillators:
Also called linear oscillators and sinusoidal oscillators, harmonic oscillators discharge signals that have simple sine waveforms. These signals decrease and increase at specified times. The energy flows from the active components then to the passive components.
There are two categories of harmonic oscillators, namely:
- Resistor capacitor or RC circuit
- Inductor capacitor or LC circuit
RC circuits are intended for lower frequency signals while LC circuits are best suited for higher frequencies.
Crystal oscillators are also harmonic oscillators, the ones that generate stabilized signals by using quartz crystals. The most popular example of a crystal oscillator is the piezoelectric oscillator.
Likewise, there are harmonic oscillators that utilize negative-resistance. These are called negative-resistance oscillators. A good example is tuned diode oscillator.
Alternatively called non-sinusoidal oscillators, relaxation oscillators exchange energy between active and passive components, but the oscillation frequency is dependent on the discharging and charging time-constants. It generates non-sinusoidal outputs of varying types. Common examples are sawtooth signals and rectangular or square waves.
Relaxation oscillators’ output frequencies range from 0 Hz to 20MHz as compared to harmonic oscillators’ 20Hz to 1 GHz.
Common Oscillator Applications
Oscillators are used for different applications and purposes, including the following:
- For quartz wristwatches
- In different communication, TV, and radio devices
- In various types of video and audio systems
- In buzzers and alarms
- In metal detectors, computers, RF and ultrasonic applications, inverters, and stun guns
- For dancing lights and other decorative lights