https://en.wikipedia.org/wiki/Electronic_oscillator

An electronic oscillator is an electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave.^[1][2] Oscillators convert direct current (DC) from a power supply to an alternating current (AC) signal. They are widely used in many electronic devices. Common examples of signals generated by oscillators include signals broadcast by radio and television transmitters, clock signals that regulate computers and quartz clocks, and the sounds produced by electronic beepers and video games.^[1]

Oscillators are often characterized by the frequency of their output signal:

• A low-frequency oscillator (LFO) is an electronic oscillator that generates a frequency below ≈20 Hz. This term is typically used in the field of audio synthesizers, to distinguish it from an audio frequency oscillator.
• An audio oscillator produces frequencies in the audio range, about 16 Hz to 20 kHz.^[2]
• An RF oscillator produces signals in the radio frequency (RF) range of about 100 kHz to 100 GHz.^[2]

Oscillators designed to produce a high-power AC output from a DC supply are usually called inverters.

https://zh.wikipedia.org/wiki/电子振荡器

电子振荡器（英语：electronic oscillator）是用来产生具有周期性的模拟信号（通常是正弦波或方波）的电子电路。^[1][2] 通常由放大电路、选频网络、正反馈网络和稳幅环节组成^[3]。振荡器将电源提供的直流（DC）转变成交流信号。它们被广泛应用于许多电子设备中。由振荡器产生信号的常见例子有无线电和电视发射机广播的信号，调节计算机和石英钟的时钟信号，和电子传呼机和电子游戏发出的声音。^[1]

振荡器通常用他们输出信号的频率描述：

• 低频振荡器（low-frequency oscillator, LFO）是指产生频率在20 kHz以下的（有的定义在0.1到10赫兹之间）交流信号振荡器。它通常用在音讯合成器中，用来区别其他的音讯振荡器。
• 音频振荡器产生频率在音频范围内，约16 Hz到20 kHz。^[2]
• 射频振荡器产生的信号在射频（RF）范围内，约100 kHz至100 GHz。^[2]

用来由直流电源产生高功率交流输出的振荡器通常称为逆变器。

振荡器主要可以分成以下两种：谐波振荡器（harmonic oscillator）与弛张振荡器（relaxation oscillator）。

A popular op-amp relaxation oscillator.

一种普遍使用的运算放大器弛张振荡器。