Difference Between Amplifier and Oscillator

Main Difference – Amplifier vs. Oscillator

Amplifiers and oscillators are components used in electric circuits. The main difference between amplifier and oscillator is that amplifiers are used to take in an input signal and produce an output of that signal with an increased amplitude while oscillators are used to generate a periodic signal.

What is an Oscillator

In terms of electrical circuits, an oscillator is a device that produces a periodically varying signal. Typically, the signal is in the form of a  sinusoid, square, triangle or sawtooth.

The signal itself is generated from noise. The noise is picked up and then amplified by an amplifier. Then, the amplified signal is sent into a filter that selects frequencies of the required range from the signal. The resulting signal is fed back into the amplifier again,… and the process is repeated until a periodic waveform that has a single frequency and a suitable amplitude is generated. 

Oscillations in quartz crystals, which take place at a specific frequency, are often used in oscillator circuits to keep time. In radios, oscillators which are capable of producing alternating currents with adjustable frequencies are used to “tune” the radio to the frequency of signals from a particular station.

What is an Amplifier

An amplifier is an element in a circuit which accepts an input signal, and produces an output that is similar to the input signal but having a larger amplitude. An amplifier could amplify the voltage, current or power of the original signal. When power is amplified, the output signal has more energy than the input signal. In order to supply this energy, the amplifier should be connected to a power source so that it can take the energy to give to the output signal. The “amp” that electric guitars are plugged into is an amplifier.

In terms of circuit components, amplification is typically carried out by transistors or operational amplifiers (“op-amps”). Historically, vacuum tubes had been used as amplifiers (some electric guitarists still continue to use these so-called “tube amps” to generate a specific sound).

An operational amplifier

The bandwidth of an amplifier refers to the range of frequencies that an amplifier can amplify. The ratio of output to input signal is called the gain of the amplifier.

Difference Between Amplifier and Oscillator

The difference between amplifier and oscillator is in their function.

An oscillator generates a signal with a specific frequency. An oscillator itself uses an amplifier in order to generate a strong signal.

An amplifier accepts an input signal and produces an output signal, which is an amplified version of the input signal.

Image Courtesy

“Opamp” by lambda’s (Own work) [CC BY 2.0], via flickr

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