Amplification

Amplification is a process of increasing the weak signal power, it can be audio, electricity and for this, a lot of different techniques are used, like transistors and transformers. The devices which are used in this process are called amplifiers. Amplifiers are used primarily in broadcasting, wireless communication, and all kinds of audio equipment. These devices are electronic devices that increase the voltage, current, or power of signals. They are widely divided based on the strength of their signal, namely weak signal amplifiers or power amplifiers. The need for amplification is an easy way of creating a good communication link between the devices.

Amplifiers

Amplifiers are devices that increase the strength of an input signal. They are divided according to their circuit configurations and the operation modes; not all the amplifiers are the same.

They are classified according to the size of their signals.

Types of amplifiers

Weak signal amplifiers 

These are mainly used in wireless receivers. They are specially designed for extremely small input signals, and sometimes they measure only a few nanovolts. These amplifiers tend to generate less internal noise. The field-effect transistor is the device used for this application. The other applications of weak signal amplifiers include audio tape players, CD players, and acoustic instruments.

Power amplifiers

These are mainly used in HiFi audio equipment, wireless, and broadcast transmitters. The output in these devices is in watts or kilowatts, generating high power energy. A bipolar transistor is a device used as a power amplifier. Nowadays, vacuum tubes are widely used in amplifiers, especially musicians, because they provide high-quality fidelity. They usually have a gain typically ranging from a few decibels to 20dB. 

Operational amplifiers, field-effect transistors, and bipolar transistors are a few examples of amplifying devices.

The amplifiers can be assumed to be a simple block consisting of the amplifying devices mentioned above to understand them more efficiently. They consist of two input and two output terminals having a common ground, and they always have an output signal higher than the input signal, which means they have been amplified.

The amplifiers, called ideal, consist of three main properties. They are the input resistance, output resistance, and amplification (gain). Irrespective of how complex the amplifiers are, the general relationship can be found using these three properties.

Efficiency

It is the ratio of the signal power output to total power input, and it is always less than 1 and generally expressed in percentage. Power amplifiers typically have 30-50% efficiency in audio applications. Whereas in the broadcast transmitters, the efficiency ranges from 50-70%.

In the case of hifi audio power amplifiers, there is also a major role of distortion. 

Distortion measures how the output waveform is a replication of the input waveform. The fidelity of the sound will be more if the distortion is low.

Amplification factor

The extent to which the analog amplifiers increase the strength of a signal is called the amplification factor. It is also called gain. They are generally expressed in terms of power. The most common unit through which the amplification factor is expressed is the decibel(dB), a logarithmic unit. 

The amplification factor formula is given by dividing the output voltage by input voltage.

When the power ratio(output to input ratio) is 2:1, It is called the doubling of the signal strength. This translates into a gain of 3dB. If there is an increase of tenfold, that results in a gain of 10 dB. At the same time, a hundredfold increase is a gain of 20 dB. Whenever the input power is more than that of output power, the amplification factor is negative, and whenever they are equal, it is 0dB.

The wireless communication equipment can show a gain of up to 30dB. Sometimes, when there is a necessity of more than this, they have to cascade the amplifiers, but this can cause distortion.

For example, imagine we have an input signal of 2 volts and an output of 100 volts; this means the gain of the amplifier is ‘50’. In simpler words, the input signal has been increased by a factor of 50. This can be called gain or amplification. The amplification factor formula can indicate this.

Conclusion

The process through which the strength of a signal can be increased using a suitable electronic circuit called the amplifier is called amplification. The devices through which the amplification process can be done are called amplifiers, and they increase the current of the voltage of a device. They are generally divided into weak-signal and power amplifiers, and the classification is done according to their signal strength. The amplification factor formula is given by dividing the output voltage by input voltage. They are expressed in terms of power. Operational amplifiers, field-effect transistors, and bipolar transistors are a few examples of amplifying devices.