Transistors

1. Transistors made it possible to design compact, small dimensioned electronic devices which consume very little power. 2. The transistors are used for direct transformation of heat energy into electrical energy by means of thermal elements. 3. They are also used to transform radiant energy into electri­city with the help of photocells or so-called solar batteries. 4. In later years light sources and lasers were built on the basis of transistors. 5. Transistors revolutionized radio engineering and electronics. 6. Having small size and other properties, transistors make it possible to produce devices which cannot be made with vacuum tubes. 7. Transistors are extremely sen­sitive to external influences, thousandths of one per cent of admixtures changing their electrical conductive properties by hundreds of thousands times¹. 8. They are very sensitive to the action of light, nuclear particles, pressure, etc. 9. Tran­sistors being sensitive to light, engineers have to take this property into consideration. 10. Some transistors act as insulators in the darkness, cadmium sulphide presenting one of them. 11. But already under ordinary room temperature their resistances decrease millions of times. 12. This property was used as the basis for making so-called photoresistances. 13. Some of them react not only to visible light but also to ultra-violet, infra-red and X-rays, and radioactive radiation. 14. At present such photoresistances, being very small in size, are successfully used as the main elements for various measuring instruments and automatic devices. 15. The supply of transistors is inexhaustible. 16. But up to now only a limited number of them is being used for engineering purposes. 17. Semiconductors are — germanium, silicon, selenium and some of the simple compounds, like lead sulphide and arsenic and phosphoruses with indium and gallium. 18. The electrical properties of germanium may be changed, provided the latter is exposed to light. 19. A very fine technology has been developed for obtaining transistors with pre-set physical properties by introducing into them admixtures of gold, copper, nickel, zinc, etc. 20. Soviet scientists have had considerable success in developing special films² which protect the transistor crystals from outer influen­ces and change their properties, these films making it possible to create a new family of miniaturized instruments.

Пояснения к тексту

1. hundreds of thousands times — сотни тысяч раз

2. films — зд. пленки