Introduction to Amplifiers

Amplifier: The current or voltage signal is amplified several times. so that the subsequent circuit can process the signal. there are many amplifier categories .. an amplifier is a device that can enlarge the voltage or power of an input signal. It consists of an electronic tube or transistor, a power transformer, and other electrical components. It is used in communication, broadcasting, radar, television, automatic control, and other devices.
A device that increases the signal amplitude or power. It is an important component for processing signals in automated technical tools. The amplifier is amplified by the input signal to control the energy. The power consumption required for amplification is provided by the energy. For linear amplifiers, output is the reproduction and enhancement of input signals. For non-linear amplifiers, the output function is related to the input signal. The amplifier consists of a mechanical amplifier, an electromechanical amplifier, an electronic amplifier, a hydraulic amplifier, and a pneumatic amplifier. The most widely used is an electronic amplifier. With the popularization of the jet technology (see the jet components), the application of liquid or pneumatic amplifiers is also increasing. Electronic amplifiers are also divided into vacuum tube amplifiers, transistor amplifiers, solid amplifiers and Magnetic Amplifiers based on the active devices used, among which transistor amplifiers are the most widely used. In automation instruments, transistor amplifiers are often used for Voltage amplification and current amplification of signals. The main forms include single-ended amplification and push-pull amplification. It is also commonly used for impedance matching, isolation, current-voltage conversion, and charge-voltage conversion (such as charge amplifier) and a certain functional relationship (such as operational amplifier) between the output and the input using the amplifier ).
Amplifier classification:
1. General Integrated Operational Amplifier
General-purpose integrated operational amplifier is a relatively moderate technical parameter that can meet the requirements in most cases. General Integrated Operational Amplifiers are classified into type I, type II and Type III. Type I is a low-Gain Operational Amplifier, type II is a medium-gain operational amplifier, and type III is a high-gain operational amplifier. The I and II types are basically early products. Their input voltage is about 2mV, and the open-loop gain is generally greater than 80 dB.
2. High-Precision Integrated Operational Amplifier
High-Precision Integrated Operational Amplifiers refer to operational amplifiers with low offset voltage, low temperature drift, and very high gain and common mode rejection ratios. The noise of such operational amplifiers is also relatively small. Among them, the single-chip High-Precision Integrated Operational Amplifier's offset voltage can be as small as a few micro volts, the temperature drift is as small as dozens of micro volts per degree Celsius.
[Edit this section] 3. High-Speed Integrated Operational Amplifier
The output voltage conversion rate of High-Speed Integrated Operational Amplifiers is very high, and some can reach 2 ~ 3kv/μs.
4. High Input Impedance Integrated Operational Amplifier
The input impedance of the high-input impedance integrated operational amplifier is very large, and the input current is very small. Mos are usually used for the input level of such operational amplifiers.
5. Low-Power Integrated Operational Amplifier
Low-Power Integrated Operational amplifiers have very low current and power supply voltage, and the power consumption of the entire operational amplifier is only dozens of microwatts. These integrated operational amplifiers are mostly used in portable electronic products.
6. Broadband Integrated Operational Amplifier
The bandwidth of a broadband integrated operational amplifier is very wide, and its unit gain bandwidth can reach more than MHz, which is often used in a broadband amplifier circuit.
7. High-Voltage Integrated Operational Amplifier
Generally, the supply voltage of an integrated operational amplifier is less than 15 V, while that of a high-voltage integrated operational amplifier is dozens of volts.
8. Power Integrated Operational Amplifier
The output level of the power-type integrated operational amplifier can provide a relatively large power output to the load.
9. Optical Fiber Amplifier
The optical fiber amplifier can not only directly enlarge optical signals, but also provide real-time, high-gain, broadband, online, low-noise, and low-loss all-optical amplification functions, it is an indispensable key component in the next generation optical fiber communication system. Because this technology not only solves the limitations of attenuation on the transmission rate and distance of optical networks, more importantly, it has created wavelength division multiplexing in the 1550nm band, which will enable ultra-high speed, ultra-large capacity, ultra-long distance wavelength division multiplexing (WDM), and intensive Wavelength Division Multiplexing (DWDM) full-optical transmission and optical-beam transmission have become an epoch milestone in the development history of optical fiber communication. The current practical Fiber Amplifiers mainly include EDFA, SOA and FRA, the Er-doped fiber amplifier has been widely used in long-distance, large-capacity, high-speed optical fiber communication systems, access networks, optical fiber CATV Networks, military systems (radar multiplexing, Data transmission, guidance, etc) as a power amplifier, relay amplifier, and front amplifier.
Generally, an optical fiber amplifier consists of a gain medium, a pump light, and an input/output coupling structure. Currently, three types of optical fiber amplifiers are available: Er-doped optical fiber amplifier, semiconductor optical amplifier, and optical fiber Raman amplifier. According to their application in optical fiber networks, optical fiber amplifier has three main purposes: used as a power amplifier on the transmitter side to increase the power of the transmitter; used as an optical pre-amplifier before the receiver to greatly improve the sensitivity of the optical receiver; relay amplifiers in optical fiber transmission lines to compensate for Optical Fiber Transmission Loss and prolong transmission distance