###### Abstract  
This paper discusses the design of a new self-balancing amplifier of an AC component power characterized by a minimal output DC offset. The design of the amplifier is based on semiconductor technology and intended for application in low-frequency analog signal processing paths, particularly in surface-to-air missile system launcher automation circuits. The proposed solution has several design and technical-implementation advantages, whereas the primary novelty compared to the commonly used ones is the ability for self-generating a near-zero DC component value of output signal. The design features and technical parameters of the developed amplifier make it suitable for use in a wide range of devices that must ensure the stable, prolonged operation of a low-frequency power amplifier under variable weather conditions and a minimal DC offset of output signal.  
automation control; analog signal processing; self-balancing power amplifier; minimal DC offset; surface-to-air missile system +
Footnote †: journal: Applied  
disturbing the structure of its instrumentation. For obvious reasons, this paper will address only a narrow aspect of modernizing a surface-to-air missile system. We considered issues related to replacing one of the launcher automation module tube amplifier circuits with a circuit that covers a power amplifier constructed with semiconductor technology.  
In general, power amplifiers supply the required output power with minimum distortions within the assumed operating bandwidth [8]. The frequency band of processed signals enables a division into (a) low-frequency (LF) power amplifiers for boosting low-frequency signals; (b) high-frequency (HF) power amplifiers for amplifying radio band signals; and (c) very high-frequency (VHF) power amplifiers used on microwave signal processing paths [9; 10; 11; 12]. Power amplifiers first appeared in the 1910s as a consequence of the invention of triodes [13]. Vacuum tubes had been the basis for amplifier construction until the second half of the previous century. Their widespread use in older-generation missile system instrumentation dated back to the 1950s. The development of transistors in the middle of the 1950s and their popularization prompted the gradual transition from tube systems to ones that used semiconductor technology, including military technology. Metal-oxide-semiconductor field-effect transistors (MOSFETs) are particularly interesting in this context. They are characterized by very high input impedance and low output impedance [14; 15]. They can be used autonomously or in pairs with bipolar junction transistors (BJT) within LF and HF amplifier structures [10]. Despite the gradual popularization of systems based on contemporary solutions, e.g., power amplifiers constructed with GaN, GaAs, Ga\({}_{2}\)O\({}_{3}\) or SiC technologies [11; 12; 16; 17; 18; 19], amplifiers with classic MOSFET transistors are still being developed and widely used in typical applications within civilian and military technology due to their properties, availability, and price [19; 20; 21; 22].  
This paper presents a design of a new self-balancing amplifier of an AC component power characterized by a minimum DC offset of output signal. The amplifier is based on a semiconductor technology intended for application in LF analog signal processing paths, especially in anti-aircraft missile system launcher automation circuits. The proposed system has several design and technical-implementation advantages, whereas the primary novelty compared to commonly used solutions is the ability for self-generating a near-zero DC component value of output signal.  
The paper is organized as follows. Section 2.1 presents a formal approach to the issue and preliminary power amplifier project assumptions. Sections 2.2 and 2.3 offer a detailed description of the system's topology, hardware implementation, and principle of operation. Section 3 discusses the results of simulation and real device tests. Section 4 concludes the paper with a summary and final remarks.