Today one can find semi-conductors of appointed materials. Their resistance must be nearly between that of a conductor and a non-conductor. The resistance of semiconductors also depends on changes in temperature or used dashes.

The expression “admixtures” refers to the other elements mixed to the material. The complete mixture defines the semi-conductors as thyristors of type-n and type-t.

The union of type-n and type-t semi-conductors is used to produce diodes and transistors. Today silicon is surely appearing to be the most wide spread material for manufacturing semi-conductors.

Specially to send the flow of electrical current in only one sense diodes are useful. They are made of semiconductor substance. There is a layer of + (positive) combination, - (negative) construction and so-called pn-transfer known as barrier level in each diode. Electrical schemes that transform among alternating and direct electrical current are made using diodes. As diodes make current go only in one direction only half of the series or cycle is fulfilled. They call such a connection a rectifier.

LED (light diodes) is another type of diodes. Such diodes are needed in case it's important to generate light at little voltages and at the same time generate no warmth. In PC, photo cameras and mobile phones, various devices these days one can see light diodes because those diodes are used to sign the idle mode.

The development of thyristors industry was led by Moore's law. Lithography is the main factor of manufacturing different power semiconductor devices at smaller cost. As optical lithography is today outdated, there's now a tendency for new techniques. To all appearance ultraviolet lithography and nano-imprint lithography can become the successors to optical lithography. X-ray lithography and electron beam lithography these days are also thought to be of big capability.

Such a useful thing as current sensors was discovered in Russia. Sensors are needed in many devices for different purposes. The sensors find their application in commercial, manufacture and daily constructions. The form and value of the sensor can change according to the type of equipment. And the sensors can be small (as in some light detectors) or complex (detectors that signal radiation loss).

It's still impossible for the voltage sensors to work alone. There are lots of purposes for using power system dispatchers. They are useful to control system properties like voltage, frequency, power flow, to control the state of circuit breakers in subordinate station and the planned interchange of power with the several power systems. System signals and the processes against them are also in their constant control.

The controllers function correctly in all these cases if they are supplied with a complete view of the power system. The information is delivered from several PCs in different sub-stations. The developers of the RTU were the pioneers to create sub-station level data acquisition like status of CB's, disconnectors, isolators and analog values like MVAR, Hz, Amps etc. The biggest success in export belongs to Russian Federation and China.