An electronic amplifier is a device that magnifies or increases the voltage, current, or power of a signal.
An amplifier accomplishes this by taking additional power from a power supply, and producing an output signal that is an exact copy of the input signal, but of a higher amplitude.
The ratio of the output signal to the input signal is referred to as the 'gain' (G) of the amplifier.
Thus, an amplifier that outputs a voltage signal Vout that is a magnified copy of the input voltage signal Vin has a gain of G, wherein G = Vout / Vin.
An amplifier can be designed to magnify the voltage of a signal (voltage amp), the current of a signal (buffer amp), or both the voltage and current of a signal (power amp).
Electronic amplifiers can operate using either a single-sided power supply (a voltage “rail” or “bus” that's either positive or negative) or a double-sided or balanced power supply, which has both a positive and a negative supply rail aside from the ground.
If the output waveform of an amplifier is not a perfect copy of the input signal, then the amplifier is said to exhibit distortion.
One type of distortion is linear distortion, which causes an output signal to have a shape that's different from that of the input signal.
Good design of the amplifier circuit, proper selection of circuit components, and correct biasing will minimize distortion.
An electronic amplifier needs what is known as an electrical 'bias' in order to function.
The bias of an amplifier is the method by which its active devices (usually transistors) are powered up and excited in order to attain the desired amount of gain with minimum distortion.
This usually entails setting the DC component of the output signal midway between the maximum voltages available from the power supply.
It is common to see amplifiers that consist of multiple stages connected in series to attain higher gains.
Each stage of the amplifier may be a different type of amplifier to meet the requirements of each stage.
For instance, the first stage might be a Class A stage, the output of which is fed into a class AB push-pull second stage, which then drives a class G final output stage.
This design takes advantage of the strengths of each amplifier class at each stage while minimizing weaknesses.
6 comments:
An electronic amplifier is a device that magnifies or increases the voltage, current, or power of a signal.
An amplifier accomplishes this by taking additional power from a power supply, and producing an output signal that is an exact copy of the input signal, but of a higher amplitude.
The ratio of the output signal to the input signal is referred to as the 'gain' (G) of the amplifier.
Thus, an amplifier that outputs a voltage signal Vout that is a magnified copy of the input voltage signal Vin has a gain of G, wherein G = Vout / Vin.
An amplifier can be designed to magnify the voltage of a signal (voltage amp), the current of a signal (buffer amp), or both the voltage and current of a signal (power amp).
Electronic amplifiers can operate using either a single-sided power supply (a voltage “rail” or “bus” that's either positive or negative) or a double-sided or balanced power supply, which has both a positive and a negative supply rail aside from the ground.
If the output waveform of an amplifier is not a perfect copy of the input signal, then the amplifier is said to exhibit distortion.
One type of distortion is linear distortion, which causes an output signal to have a shape that's different from that of the input signal.
Good design of the amplifier circuit, proper selection of circuit components, and correct biasing will minimize distortion.
An electronic amplifier needs what is known as an electrical 'bias' in order to function.
The bias of an amplifier is the method by which its active devices (usually transistors) are powered up and excited in order to attain the desired amount of gain with minimum distortion.
This usually entails setting the DC component of the output signal midway between the maximum voltages available from the power supply.
It is common to see amplifiers that consist of multiple stages connected in series to attain higher gains.
Each stage of the amplifier may be a different type of amplifier to meet the requirements of each stage.
For instance, the first stage might be a Class A stage, the output of which is fed into a class AB push-pull second stage, which then drives a class G final output stage.
This design takes advantage of the strengths of each amplifier class at each stage while minimizing weaknesses.
An amplifier's output signal may be of different phase or polarity as the input signal.
A non-inverting amplifier maintains equal phase relationship or polarity between the input and output waveforms.
An emitter follower is a type of this amplifier, indicating that the signal at the emitter of a transistor follows the phase of the input signal.
An inverting amplifier produces an output that is of opposite polarity or 180 degrees out-of-phase with the input signal.
There are many different ways to classify amplifiers.
Amplifier classifications include the following:
1) by function;
2) by frequency range;
3) by common terminal;
4) by type of load;
5) by coupling.
Post a Comment