What is the difference between modulator and amplifier?

Answer 1

Amplifiers are circuits which transfer an input signal into an output signal.

Oscillators are autonomous circuits powered by a constant energy source.

Oscillators produce a steady state signal e.g. a square wave signal,

a sinusoidal signal or a chaotic signal.

Real world oscillators are non linear circuits.

Linear oscillators are mathematical fiction (a complex pole pair can not

balance on the imaginary axis).

Clarification. Yes, while most oscillators *do* use amplifiers with output-to-input feedback. there are some that do not.

The classic example is the now-obsolete point-contact transistor that exhibited a negative resistance, and could therefore oscillate with a two-terminal tuned circuit and no feedback. The tunnel diode, now also obsolete, also exhibits negative resistance.

Another example is the neon lamp "relaxation" oscillator that relies on a resistor-capacitor circuit's charge/discharge time. This design was also used in early oscilloscope time-bases. The Uni-junction transistor operates similarly.

Disagreements: (i) "Linear oscillators are mathematical fiction". If so, what of (for example) the Wein Bridge oscillator that uses feedback to stabilise its operating point. (ii) Oscillators may be designed to produce an intermittent ("squegging") signal, as used in some lifeboat/search and rescue transmitters, or the super-regenerative receiver.

The (very) basic answer is that an oscillator is an amplifier with a positive feedback path engineered into. This sets up a situation where the feedback returns a bit of the output signal to the input of the stage to "keep it going" and to permit it to sustain the "continuous" output of a (frequency controlled) signal.

All amplifiers can be made to oscillate, and all oscillators amplify. The difference is in how we set them up, which we will do in accordance with what we want out of them.

Clarification: Note that the loop gain must be greater than one for tuned-circuit oscillators. An emitter-follower (with a gain less than 1.0) can be made to oscillate only if the tuned circuit has a voltage gain ("step-up").

To understand the differences it is helpful to look at the similarities. They both need some form of amplifier to work.

The "goodness" of an amplifier is specified by the amount of gain (among other things) it possesses i.e. by how much it amplifies which is measured by seeing how much bigger the output is compared with the input.

All circuits contain feedback paths where part of the output signal finds its way back to the input - some intentional (as in an oscillator) and some unwanted (as in an amplifier).

If we start with an ordinary amplifier circuit and gradually increase the gain of the amplifying bit we will eventually get to the point where the specific combination of that amount of gain and the characteristics of the feedback path result in enough energy travelling through the feedback path to cause the amplifier to become unstable. In other words it oscillates!

The frequency of oscillation is largely determined by the characteristics of the feedback path and when the feedback signal is big enough and is in phase with the original input signal it oscillates.

Answer 2

Oscillator is a generalized term for an active circuit that produces a periodic waveform. Inverter is a specialized term for a system that contains an oscillator and produces large amounts of power(such as AC) from a source (like DC battery).

Amplifiers produce power gain. Transformers only produce voltage or curren

Answer 3

An ordinary amplifier is the one which amplifies the input signal alone.. but an Operational amplifier performs the functions of summing, inverting, differentiation, integrating, division, multiplication etc..of the input signal..

Answer 4

Amplifier and Modulator both are almost same but they are quite different from each other.Amplifier is used to amplify the message signal for small distance while modulator is used to modify those signals which are to be transmitted for very long distances with the help of carrier wave.

Let's see with example:

If we have to transmit a song to your neighbour from your home, you can use amplifier for this purpose.For example,we can accomplish our aim with the help of big speaker.But just if this distance is at america,then how big amplifier you use,its impossible.So,to overcome this problem,modulator is used that transmit message signal without distortion.

Answer 5

Amplifier amplifies the input signal whereas an Oscillator generates a sinusoidal signal!

Answer 6

Difference between oscillator and transistor

Answer 7

An oscillator will generate a waveform. An amplifier takes a small wave and 'amplifies' it to a big wave.

Answer 8

An oscillator is part of a generator. A generator has many more functions than a simple oscillator.