International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Еlectronics is the most progressive branch of mechanical engineering since the 1960s. Specific for the development of this industry in our country is that each technological development or the creation of material conditions for its implementation in the period from 1960 by the end of the socialist period, it had received support at the highest state level, in the form of continuous promotion, smooth financing, the provision of embargoed high-deficit technologies by special services and the wide opening of the economy to integration into production. Significant for the development of the industry in our country is the specialization in the production of electronic computers, which was won in a competitive competition between all member countries of the COMECON on the basis of previously achieved in Bulgaria high scientific results in the field.

The contemporary high-efficiency education in the sphere of digital technologies requires the employment of such demonstration methods and tools, which enable visual representation and illustration of the computer technologies in an attractive and accessible form. The aim is to let the learners, even if unprepared in the basic scientific and technological areas – physics, mathematics, informatics, electrical and electronic engineering, etc., easily to understand the working principle of the digital computer.
The goal of this development, the subject of the current material, is the creation of a digital computer, realized using bistable relays (BRC44). The application is with the education of students and pupils in universities and schools in the educational subjects: informatics, computer science, information technologies, electronics, and physics.
The BRC44 computer is a 4-bit computer with 4-bit data bus to the ROM memory. The employed architecture is of the Harvard type. The computer uses only bistable relays as active electronic elements without the implementation of monostable relays, vacuum electronic tubes, transistors and integrated circuits.
The bistable relay based computer is designed around four master printed circuit boards, on which are mounted the bistable relays, the semiconducting diodes, the light emitting diodes, etc.
The approbation of the BRC44 prototype with students demonstrated the easy perception of the working principle of the digital computer, due to the pictorial presentation, the light indication of the current state of each relay, etc. The computer is protected with a utility model registered at the Patent Office of the Republic of Bulgaria.

The present article offers an approach for more effective fundamental preparation for the work with CAD systems within the technical field of Basics in Construction. The approach is based on developed, and justified versions for practical application of fundamental computer aided designing of hydro mechanical elements and mechanical drives that are used throughout the training of students. Their 3D geometrical models present options for computer aided simulation, size analysis during designing of assembled units as well as options for training of master degree students in an optional field of Expert Systems. The obtained results are also useful for the purpose of better connections between general technical subjects and profiling subjects.