An oscillator is a device for energy conversion – it converts direct current energy into alternating current energy of a certain frequency. The circuit that constitutes an oscillator is called an oscillation circuit. Oscillators can mainly be divided into two types: harmonic oscillators and relaxation oscillators.
Introduction

An oscillator (in English: oscillator) is an electronic component used to generate repetitive electronic signals (usually sine waves or square waves). The circuit it constitutes is called an oscillation circuit. It is an electronic circuit or device that converts direct current into an alternating current signal with a certain frequency. There are many types, classified by the excitation method as self-excited oscillators and external-excited oscillators; by circuit structure as resistive-capacitive oscillators, inductive-capacitive oscillators, crystal oscillators, and tuning fork oscillators; and by output waveform as sine waves, square waves, sawtooth waves, etc. It is widely used in the electronics industry, medical field, scientific research, etc.
A low-frequency oscillator (low-frequency oscillator, or LFO) is an oscillator that generates alternating signals with a frequency ranging from 0.1 hertz to 10 hertz. This term is usually used in audio synthesis to distinguish it from other audio oscillators.
Oscillators can be mainly divided into two types: harmonic oscillators and relaxation oscillators.
They are mainly applicable to major and medium-sized universities, medical institutions, petrochemical industries, health and epidemic prevention, environmental monitoring and other scientific research departments for the oscillation cultivation of various liquid and solid compounds in biology, biochemistry, cells, and bacterial strains.
Self-excited multivibrator is also called an unstable circuit. The collector of two transistors each has a capacitor connected to the base of the other transistor, which serves as an AC coupling function, forming a positive feedback circuit. When the power is turned on, one transistor conducts first and the other transistor is cut off. At this time, the collector of the conducting transistor has an output, and the capacitor of the collector couples the pulse signal to the base of the other transistor, causing the other transistor to conduct. Then the originally conducting transistor is cut off, and this process alternates between conducting and cutting off the two transistors, thus generating an oscillating current.
Due to the impossibility of the components having completely identical parameters, the states of the two transistors change at the moment of power-on. This change becomes increasingly intense due to the positive feedback effect, resulting in a temporary stable state. During the temporary stable state, the other transistor gradually charges through the capacitor and conducts or cuts off, causing a state flip and reaching another temporary stable state. This repeats in a cycle to form oscillation.
Sine wave oscillator
An oscillator that can output sine waves is called a sine wave oscillator.
Sine wave oscillators mainly include LC oscillators and RC oscillators.
The most basic components of an oscillator
1 Transistor amplifier; (controls energy)
2 Positive feedback network; (feedback part of the output signal to the input)
3 Frequency-selecting network; (used to select the required oscillation frequency to enable the oscillator to oscillate at a single frequency, thereby obtaining the required waveform.)