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An amplifier is a device that uses tubes or transistors, power supply, transformers, and other electrical components to increase the voltage or power of an input signal. The amplifier's amplification effect is achieved by regulating the energy source with the input signal, and the energy source provides the power consumption required for the amplification. Communications, broadcasting, radar, television, automatic control, and other systems all employ amplifiers.
An amplifier is a device that boosts a signal's amplitude or strength, and it's a crucial part of signal processing in automation technology applications. The amplifier's amplification effect is achieved by regulating the energy source with the input signal, and the energy source provides the power consumption required for the amplification. The output of linear amplifiers is the replication and augmentation of the input signal. The output of nonlinear amplifiers is a function of the input signal.
The term "amplification" refers to the process of passing a weak electrical signal through a device to produce a signal output with the same waveform as the weak signal but significantly higher amplitude. A transistor amplifier circuit is what this device is.
The amplifier circuit's amplification effect is primarily to transfer energy from the DC power supply UCC to the output signal.
The transistor is the heart of the amplifier circuit. As a result, if the amplifier circuit wishes to amplify the little signal input, it must first confirm that the transistor is operating in the amplifying area.
Transistor amplifier circuits are typically configured in one of three ways:
The goal, regardless of the amplifying circuit's layout, is to transmit the input weak signal through the amplifying circuit, where its signal amplitude will be greatly increased when it is output.
In electronic technology, the common emitter amplifier circuit is the most extensively used type of amplifier circuit. The circuit's general structure is as follows:
Figure. 1
1. Gain
The gain of an amplifier relates to how much it can boost the amplitude of a signal. This parameter is frequently expressed in decibels (dB). Gain is defined as the output amplitude divided by the input amplitude into mathematical terms.
2. Output dynamic range
The range between the greatest and least useful output amplitudes is known as the output dynamic range, and it is commonly expressed in decibels (dB). The dynamic range of an amplifier is defined as the lowest practical amplitude that is not limited by output noise.
3. Bandwidth and Rise Time
(1) The difference between the low-frequency and high-frequency half-power points is commonly used to describe an amplifier's bandwidth (BW). As a result, it's commonly referred to as -3dB BW. Other response tolerances' bandwidths are sometimes defined as well (-1dB, -6dB, etc.). A good audio amplifier's -3dB bandwidth, for example, will be roughly 20 Hz to 20 000 Hz (the frequency range of normal human hearing).
(2) When the step signal is input, the rise time of the amplifier refers to the time when the output terminal changes from 10% to 90% of the final output amplitude value.
4. Ideal frequency characteristics
The phase shift is proportional to frequency and the gain is constant. That is, for signals of different frequencies, the amplifier has the same degree of amplification, and the phase shift for signals of any frequency is zero.
5. Settling time and offset
The time it takes for the output amplitude to settle within a particular ratio of the final amplitude (e.g. 0.1 percent).
6. Efficiency
The amount of input energy applied to the amplifier output is referred to as efficiency. The efficiency of a Class A (Class A) amplifier is quite low, at 10-20%, with a maximum of no more than 25%. Modern Class A and B (Class AB) amplifiers have efficiency ranging from 35 to 55 percent, with a theoretical maximum of 78.5 percent. The efficiency of commercial Class D (Class D) amplifiers has been claimed to be as high as 97 percent. The useable fraction of the total power dissipation is limited by the amplifier's efficiency. It's worth noting that more efficient amplifiers lose less heat and, in most cases, don't require fans in systems with multiple watts.
7. Slew rate
The slew rate is the rate of change of the output voltage variable, often defined as volts per second (or microseconds).
8. Noise figure
is a metric for how much noise the amplification process introduces. In electrical devices and components, noise is unpleasant yet unavoidable. With zero input, noise is measured in decibels or peak output voltage at the amplifier's output. It can also be determined by the difference between the input and output signal's signal-to-noise ratio. The noise figure of the amplifier is the number of dB that the signal-to-noise ratio of the output signal has worsened.
9. Linearity
A perfect linear amplifier should exist, however, real amplifiers are linear only within specific practical limits, and distortion happens otherwise. When the driving amplifier's signal rises, the output rises with it until it reaches a particular voltage value, causing a portion of the amplifier to saturate and no longer be able to increase the output, which is known as "cut-off distortion" (cut-off distortion, clipping distortion). There is also "saturation distortion" (undercutting distortion). The characteristics of the transistor and the choice of the static operating point are directly related to the source of distortion.
The successful development and manufacturing of optical amplifiers is a significant milestone in optical fiber communication technology, paving the way for optical multiplexing, optical arc communication, and all-optical networks. The purpose of an optical amplifier is to amplify the optical signal, as the name suggests.
Gain medium, pump light, and input and output coupling structures are all common components of fiber amplifiers. Fiber amplifiers can be divided into three categories: erbium-doped fiber amplifiers, semiconductor optical amplifiers, and fiber Raman amplifiers. Fiber amplifiers have three different uses in fiber networks, depending on their application: they are used as power amplifiers on the transmitter side to improve the emission-quality; they are used as power amplifiers on the receiver side to improve the emission-quality, and they are used as power amplifiers on the receiver side to improve the emission quality. It's used as an optical pre-amplifier before the receiver to considerably improve the sensitivity of the optical receiver; and as a repeater amplifier in the optical fiber transmission line to compensate for the optical fiber transmission loss and increase the transmission distance.
Optical amplifiers feature real-time, high-gain, wideband, low-noise, low-loss all-optical amplification characteristics, and are critical fundamental components in the new generation of optical fiber communication systems.
Principle and classification of fiber amplifier
The principle of EDFA
A three-level system is required for the EDFA pumping operation. Most of the Er3+ ions in the ground state can be pumped to the excited state, and the Er3+ ions in the excited state can be swiftly removed, by injecting sufficiently strong pump light into the erbium-doped fiber. A metastable condition can be reached by radiatively transferring energy. It is easy to generate a population inversion between the metastable and ground states due to the long lifetime of Er3+ ions at the metastable energy level. When a signal photon goes through an erbium-doped fiber, it interacts with Er3+ ions in the metastable state, causing a stimulated radiation effect that generates a huge number of photons that are identical to themselves. The signal photons carried via the erbium-doped fiber rapidly increase at this moment, resulting in signal amplification. When Er3+ ions are in a metastable condition, spontaneous emission (ASE) is produced in addition to stimulated emission and stimulated absorption, resulting in EDFA noise.
High gain, low noise, wide frequency bandwidth, high output power, low connection loss, and polarization insensitivity are all advantages of the Erbium -Doped Fiber Amplifier (EDFA). In the situation of distortion, stable power amplification is achieved.
Structure of EDFA
An erbium-doped fiber (EDF), a pump light source, a coupler, and an isolator are the essential components of an EDFA construction.
The basic component of EDFA is erbium-doped fiber. The matrix is made of silica fiber, and the core is doped with erbium ions, which are a solid laser working ingredient. The optical isolator's job is to prevent light from refracting back into the amplifier, hence it must have a low insertion loss, regardless of polarization, and isolation of more than 40 dB.
Characteristics and performance indicators of EDFA
The gain characteristic represents the amplifier's amplification capabilities, which is defined as the output power to input power ratio. Pout and Pin are the continuous signal power at the amplifier's output and input, respectively. The gain coefficient denotes the amount of gain obtained by passing 1 mW of pump light power through the fiber amplifier. The pump strength determines g0, which is the small-signal gain coefficient. The gain coefficient decreases as the signal power increase due to the gain saturation phenomenon; Is and Ps are the saturated light intensity and saturated light power, respectively, which are quantities indicating the properties of the gain material, and they are related to the doping coefficient, fluorescence time, and transition cross-section.
The difference between gain and gain coefficient is that gain is primarily concerned with the input signal, whereas gain coefficient is mostly concerned with the input pump light. Furthermore, the gain is affected by pumping circumstances (such as pumping power and pumping wavelength), with the most common pumping wavelengths being 980 nm and 1 480 nm. Because the gain coefficients differ everywhere and the gain must be integrated throughout the entire fiber, this characteristic can be utilized to pick the fiber length to create a somewhat flat gain spectrum.
EDFA bandwidth
The gain spectrum bandwidth refers to the wavelength range in which signal light can be amplified to a particular degree. The actual EDFA's gain-frequency variation connection is far more intricate than the theoretical one, and it is additionally influenced by the matrix fiber's doping. EDFA has a gain spectrum width of hundreds of nanometers and a reasonably flat gain spectrum. ED-FA has a gain spectrum ranging from 1 525 to 1 565 nm.
Cascade structure of EDFA
The amplification of optical signal strength by EDFA frequently uses a cascade mechanism, such as two-stage or three-stage amplification, especially in high-power (watt-level) applications of wireless optical communication. Because the optical isolator effectively suppresses the second segment, the cascade approach is used: an optical isolator is introduced into the erbium-doped fiber (EDF) of the EDFA to construct a two-stage cascaded EDFA with an optical isolator. The reverse spontaneous emission (ASE) of EDF prevents it from entering the first EDF, reducing pump power consumption on the reverse ASE and allowing the pump photons to be converted more efficiently into signal light energy, resulting in improved EDFA gain, noise figure, and output power characteristics. The 1 550 nm optical signal of 1-2 mW is amplified to roughly 1 W by EDFA in this research using MW cascade amplification.
An LD laser generates the optical signal, which is a modulated signal. A single-clad erbium-doped fiber amplifier is employed for the initial stage of amplification, and a 980 nm single-mode semiconductor laser is used as a pump source to boost the optical power to roughly 50 mW. The optical signal is stably and consistently amplified to a particular power in the first stage, which ensures the integrity of the entire optical signal while also providing a greater optical power base for the following level of optical amplification. The multi-mode semiconductor laser pump source multiplies the optical power to around 1 W in the second stage, which uses a double-clad fiber amplifier. The core of the double-clad fiber amplifier is larger than the core of the single-clad fiber amplifier, allowing the pump power to be successfully coupled into the core, allowing the second-stage optical signal output power to reach the watt level.
Erbium-Doped Fiber Amplifier
The active medium in erbium-doped fiber amplifiers is erbium-doped fiber. When the pump light is applied to the EDF, the ground state Er3+ can be pumped to the excited state, and the excited state Er3+ can be discharged swiftly and non-radiatively. Transfer to the metastable state: Because Er3average +'s residence period in the metastable state is 10ms, a population inversion between the metastable and ground states is easy to generate. The laser radiation effect generates a huge number of photons that are identical to themselves, causing the signal photons to rapidly rise, allowing a constantly amplified optical signal to be obtained at the output end.
The Erbium-Doped Fiber Amplifier (EDFA) has been developed and applied to optical fiber communication systems in the 1.55mm frequency band since the late 1980s and early 1990s, promoting the development of optical fiber communication in the direction of all-optical transmission. The C-band EDFA is the most mature; the widely used C-band EDFA works in the window with the lowest fiber loss of 15301565nm, and has the advantages of large output power, high gain, polarization-independent, low noise figure, amplification characteristics independent of system bit rate and data format, and A series of characteristics such as amplifying multiple wavelength signals at the same time have been widely used in long-distance optical communication systems. The downside is that the C-Band EDFA's gain bandwidth is just 35nm, which only covers a portion of the silica single-mode fiber's low-loss window, limiting the number of wavelength channels that the fiber can accept intrinsically.
However, with the rapid advancement of Internet technology, optical fiber transmission networks' transmission capacity must be regularly increased. When it comes to increasing transmission capacity, there are three basic options:
increase the transmission rate per wavelength;
reduce wavelength spacing;
Increase the total transmission bandwidth.
Semiconductor Optical Amplifier
Semiconductor Optical Amplifier (SOA) is a type of traveling wave amplifier created using a communication laser-like method. The laser diode can achieve optical amplification for the input coherent light when the bias current is less than the oscillation threshold. Because semiconductor amplifiers have small size, a relatively simple structure, low power consumption, long life, are easy to integrate with other optical devices and circuits, are suitable for mass production, are low cost, and can perform gain and switching functions, among other things, they are used in all-optical wavelength conversion. The successful creation of semiconductor optical amplifiers composed of strained quantum well materials, which has attracted substantial research interest in SOA, has sparked extensive interest in exchange, spectral inversion, clock extraction, and demultiplexing.
Domestically, the Wuhan Institute of Posts and Huazhong University of Science and Technology successfully developed a key device in the optical network—a semiconductor optical amplifier—and quickly realized productization, becoming the first company after Alcatel to be able to supply the international market in batches for optical switches. It is a supplier of semiconductor optical amplifiers, which is an important step in the commercialization of my country's strain quantum well devices. However, semiconductor optical amplifiers have faults such as high noise, low power, sensitivity to crosstalk and polarization, considerable loss when connecting with optical fibers, and poor operational stability when compared to erbium-doped fiber amplifiers. There is still a significant gap in the amplifier. Because the semiconductor optical amplifier covers the 1300-1600nm range, it can be used as an optical amplifier for both the 1300nm and 1550nm windows, and there is no need for gain locking in the DWDM multi-wavelength fiber communication system, so it may be used for more than just that. Optical amplifiers are a good solution, and they can help with the implementation of 1310nm window DWDM systems.
Fiber Raman Amplifier
Stimulated Raman Scattering (SRS) is a nonlinear phenomenon in optical fibers that transfer a tiny fraction of the incident optical power to a Stokes wave with a lower frequency. When the weak signal wavelength is positioned inside the pump light's Raman gain bandwidth, the weak signal light can be amplified. A fiber Raman amplifier is an optical amplifier that uses the stimulated Raman scattering principle ( FRA).
Fiber Raman amplifiers have received a lot of interest in recent years and have become a hot topic in research and development. They have a number of advantages:
The gain medium is an ordinary transmission fiber with good fiber system compatibility.
(2) The gain wavelength is defined by the pump light wavelength and is unaffected by other parameters. In theory, any wavelength of signal light can be amplified as long as the wavelength of the pump source is appropriate.
(3)Good temperature stability, high gain, low crosstalk, low noise figure, wide spectrum range, and low noise figure.
Because the fiber Raman amplifier has so many advantages, it can amplify wavelength bands that the erbium-doped fiber amplifier can't, and it can perform optical amplification in the spectral range of 1292-1660nm for a much wider gain bandwidth than the EDFA; gain bandwidth is also much wider than the EDFA. The medium is conventional optical fiber, and FRA can be discrete or dispersed. Distributed optical fiber Raman amplifiers can enhance signal light online and boost optical amplification transmission distance. It's particularly well suited to 40Gbit/s high-speed optical networks. Because amplification is distributed along the optical fiber rather than concentrated in submarine optical cable communication systems, the optical power of the input optical fiber is substantially lowered, and the nonlinear effect, particularly the four-wave mixing effect, is greatly reduced. This is really applicable. FRA is a supplement, not a replacement, for EDFA. The benefit of using distributed fiber Raman amplifiers is that the combination of the two can create a gain-flat broadband greater than 100 nm.
Fiber Raman amplifiers, on the other hand, have the drawback of requiring extra-high-power pump lasers. The following are the primary methods for resolving this issue: To begin, researchers are looking toward pump lasers with lower threshold powers so that high-power semiconductor lasers can be employed as Raman pumps. The second is to improve pump laser research and development to achieve higher output power; the third is to multiplex the wavelengths of numerous pump source lasers using an array and single-chip combination to achieve high output power. This approach may change the gain slope by adjusting the strength of individual lasers, in addition to providing a broadband gain spectrum.
An operational amplifier is a common integrated circuit that combines multiple transistors, resistors, capacitors, and other components into a tiny chip to perform amplification in a predetermined circuit configuration. Because the operational amplifier is an integrated circuit, it offers all of the benefits of an integrated circuit, including excellent amplification accuracy, huge gain, low noise, and ease of design. Designers utilize a large number of operational amplifiers to replace traditional triodes in some cases with higher requirements for amplifying components.
Operational amplifiers have a wide range of applications. It may do "operation" duties such as addition, subtraction, multiplication, and division of signals in addition to standard amplification.
How Operational Amplifiers Work
The operational amplifier has two input terminals and one output terminal, as shown in the figure (the input terminal marked with a "+" sign is a "non-inverting input terminal" that cannot be referred to as a positive terminal), and the other one marked with a "one" sign is a "non-inverting output terminal" that cannot be referred to as a positive terminal). The input terminal is a "inverting input terminal," which means it cannot be referred to as a negative terminal. If the same signal is repeatedly input from the two input terminals, the output terminal will produce an output signal with the same voltage but opposite polarity: The signal at the non-inverting input terminal is in phase with the signal at the inverting input terminal, however the signal at the inverting input terminal is out of phase.
The power supply connected to the operational amplifier can be a single power supply or a dual power supply, as shown in Figure 1-2. Op amps have some very interesting properties that can be used flexibly for many unique uses. In general, these properties can be combined into two:
1. The magnification of the operational amplifier is infinite.
2. The input resistance of the operational amplifier is infinite and the output resistance is zero.
To begin with, the operational amplifier's magnification is unlimited, which means that as long as the input voltage at its input is not zero, the output voltage will be as high as the positive or negative power supply. It was supposed to be infinitely high. Limitations on supply voltage To be more specific, if the voltage input at the non-inverting input terminal is greater than the voltage input at the inverting input terminal, even if it is only slightly higher, the operational amplifier's output terminal will output the same voltage as the positive power supply voltage; The voltage input at the phase input terminal is greater than the voltage input at the non-inverting input terminal, and the operational amplifier's output terminal will produce a value equal to the negative supply voltage (if the operational amplifier uses a single supply, the output voltage is zero).
Second, because the magnification is infinite, the operational amplifier can't be utilized as an amplifier directly; instead, the output signal must be returned back to the inverting input (known as negative feedback) to minimize the magnification. The function of R1 is to return the output signal to the operational amplifier's inverting input terminal, as indicated in the left figure in Figure 1-3. The amplification factor of the circuit will be diminished since the voltage of the inverting input terminal and the output is opposite., is a negative feedback circuit, and the resistor Rf is also known as a negative feedback resistor.
Furthermore, because the op amp's input is infinite, the op amp's input receives only voltage, not current. Similarly, if we picture an infinite resistor between the op amp's non-inverting and inverting inputs, the voltage applied across this resistor cannot create a current, and hence there is no current. According to Ohm's law, there will be no voltage at the resistor's two ends, so we may assume that the voltage at the operational amplifier's two input terminals is the same (the voltage in this situation is similar to shorting the two input terminals with a wire, so we call this phenomenon again). "Void Short" is a short story about a void.
Classification of Operational Amplifiers
Operational amplifiers can be classified into the following groups based on their characteristics:
Low price, vast quantity, and wide range of products are the key qualities of this general-purpose operational amplifier, and its performance indicators are ideal for general use.
Low temperature drifts operational amplifier: It is always intended that the offset voltage of the operational amplifier in automatic control instruments such as precision instruments and weak signal detection is modest and does not fluctuate with temperature.
The differential mode input impedance is quite high, while the input bias current is very tiny in a high-impedance operational amplifier. The rid is usually > 1G1T, and the IB is a few picoamps to tens of picoamps.
The main characteristics of a high-speed operational amplifier are the rapid slew rate and wide frequency response.
With the increase in the application range of portable instruments, it is vital to employ low-voltage power supplies and low-power consumption operational amplifiers, because the major advantage of electronic circuit integration is that it can make complex circuits small and light.
Operational amplifier with high voltage and high power: The operational amplifier's output voltage is primarily restricted by the power source.
The range problem will be included in the usage of instruments with a programmable control operational amplifier. The magnification of the operational amplifier must be changed in order to produce a fixed voltage output.
In many circumstances, the host's rated output power is insufficient to drive the complete audio system, necessitating the use of a power amplifier. A power amplifier should be installed between the host and the playback device at this time to fill in the required power gap, and power amplifiers play a critical role in the overall sound system's "organization and coordination," and to some extent determine whether the entire system can produce good sound quality output.
Power Amplifier Fundamentals
Using the current control function of the triode or the voltage control function of the field effect transistor, the power supply's power is turned into a current that changes according to the input signal. Because sound is made up of waves of varying amplitudes and frequencies, or AC signal current, the triode's collector current is always times the base current, and represents the triode's AC amplification factor. If a small signal is injected into the base, the current flowing through the collector will be times the base current, and the signal will be isolated with a DC blocking capacitor, yielding a big signal with a current (or voltage) that is times the original. This phenomenon becomes the amplification of the triode. effect. After continuous current amplification, power amplification is completed.
Classification of power amplifiers
The output circuit form of the power amplifier stage determines the division of the power amplifier circuit. The following are the most common audio power amplifiers:
1. Coupled to a transformer Tube amplifiers primarily use Class A amplifier circuits.
2. Some tube amplifiers with high output power use a transformer-coupled push-pull power amplifier circuit.
3. The OTL power amplifier circuit is mostly employed in small-output amplifiers.
4. The OCL power amplifier circuit is a widely utilized amplifier circuit that is frequently employed in power amplifiers with high output power needs.
5. The BTL power amplifier circuit is mostly employed in situations when more output power is required.
Among them, OTL, OCL and BTL power amplifier circuits are mainly used in transistor amplifiers.
Types of Power Amplifiers
The output of the power amplifier circuit determines the division of the circuit. There are three sorts of amplifiers in the amplifier circuit, depending on the signal working state of the triode when amplifying the signal and the triode's quiescent current: a class A amplifier circuit, a class B amplifier circuit, and a class A and B amplifier circuit.
There are numerous additional amplifier circuits, such as super class A, in addition to the three mentioned above. Only Class A amplifier circuits and Class A and B amplifier circuits are employed in the audio system since nonlinear signal distortion is not permitted.
Class A amplifier
A class A amplifier uses a triode to amplify both the positive and negative half cycles of the signal at the same time by applying a proper static bias current to the amplifier tube. The signal amplitude in the output stage of the power amplifier is already very great in the power amplifier circuit. This circuit is known as a class A amplifier because the positive and negative half cycles of the signal are still boosted by a triode.
The static working current of the power amplifier tube of the class A amplifier is set relatively large in the power amplifier output stage amplifier circuit, and it should be set in the middle of the amplification area, so that the signal positive and negative half-cycles have the same linear range, and the signal positive half cycle enters the transistor saturation when the signal amplitude is too large (beyond the linear region of the amplifier tube). The degree of clipping for the signal's positive and negative half-cycles is the same at this moment.
The main characteristics of the Class A amplifier circuit are as follows:
1. The sound quality of a Class A power amplifier is the best in an audio system. The nonlinear distortion of the signal is very low since the positive and negative half cycles of the signal are amplified by a triode, which is the main advantage of the Class A power amplifier.
2. The signal's positive and negative half-cycles are amplified by the same triode, limiting the amplifier's output power; in general, the output power of a Class A amplifier cannot be made extremely big.
When there is no input signal, the power transistor's static working current is relatively high, and the DC power supply's consumption is comparatively high.
Class B amplifier
No static bias current is given to the triode in a class B amplifier, and two symmetrical triodes are employed to amplify the positive and negative half cycles of the signal, respectively, before the positive and negative half cycles are generated on the amplifier's load. A signal that is completely periodic.
Because this type of amplifier does not provide static current to the power amplifier's output tube, it produces crossover distortion, which is a type of nonlinear distortion that severely degrades sound quality. As a result, audio amplifier circuits cannot use Class B amplifier circuits.
Class A and B amplifiers
To avoid crossover distortion, the input signal must avoid the triode's cut-off area, and a little static bias current can be provided to the transistor, allowing the input signal to "ride" on a small static bias current, avoiding crossover distortion. The triode's cut-off area is set to ensure that the output signal is not distorted.
The following are the major properties of class A and B amplifier circuits:
This amplifier employs two triodes to magnify the positive and negative half cycles of the input signal, similar to the class B amplifier circuit, but adds a little static bias current to the two triodes, causing the triode to enter the amplification Area.
(b) Because the static DC bias current provided to the triode is quite modest, the amplifier's DC power supply consumption is comparatively low (far lower than that of a class A amplifier) when no input signal is present. It has the advantages of power savings while also having no signal distortion because the additional bias current overcomes the triode's cut-off area. It also has the advantage of no Class A amplifier nonlinear distortion. As a result, A and B amplifiers combine the benefits of class A and class B amplifiers while also addressing their faults. Class A and B amplifiers are extensively employed in audio power amplifier circuits because they have no crossover distortion and have the advantages of high output power and low power consumption.
When the triode's static DC bias current is too little or not present in this amplifier circuit, it becomes a class B amplifier, resulting in crossover distortion.
push-pull amplifier
In power amplifier circuits, a great number of push-pull amplifier circuits are used. Two triodes are utilized to create a first-stage amplifier circuit in this circuit. Use another triode to amplify the negative half cycle of the signal, and the half-cycle signals supplied by the two triodes are combined on the amplifier load to obtain a full cycle output signal.
When one triode is in the on and amplifying state in a push-pull amplifier circuit, the second triode is in the off state. The originally on and amplified triode reaches the cut-off state when the input signal shifts to another half cycle, while the original cut-off transistor shuts off. The triode switches from conduction to amplification and the two triodes alternately conduct amplification and cut-off changes, resulting in a push-pull amplifier.
Complementary Push-Pull Amplifier
Utilize two transistors with different polarities, with separate input polarities of the different polarities, and use one signal to excite two different polarities, eliminating the requirement for two excitations of equal magnitude and phase. Signal.
A "complimentary" circuit is one that exploits the complementary features of NPN and PNP transistors to simultaneously activate two transistors with a signal, and a complementary amplifier circuit is one that is made up of complementary circuits. Because one triode is turned on and amplified while the other triode is turned off and functions in a push-pull condition when the VT1 and VT2 tubes are operating, the amplifier is known as a complementary push-pull amplifier.
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