The magnetic amplifier is one of types of the electronic converter. This device uses interaction of currents and magnetic fields to increase signal amplitude. Such type of amplifiers is a replacement of vacuum tubes. From vacuum devices they are distinguished by small sensitivity to differences of tension.
History of magnetic amplifiers
The first magnetic amplifiers were created at the beginning of the nineteenth century. However they were widely used only in the second half of the twentieth century.
The USA and Germany were the first countries in which reliable magnetic amplifiers appeared. There they at first were made for the military purposes during World War II. In the mid-fifties magnetic amplifiers replaced many lamp which performed the same functions, but were more fragile. They are still applied in the devices used in adverse conditions.
The magnetic amplifier is capable to catch practically all range of radio-frequency signals. This property can be used for sending radiograms for long distances. For this reason the first radio fans experimented with use of big magnetic amplifiers for transmission of messages by the Morse alphabet across the ocean.
Device and principle of operation of magnetic amplifiers
Magnetic amplifiers consist of two repeating wire hanks, will wrap up each of which around the magnetic core. For its work on one of coils the alternating voltage and current moves. When loading on one of coils reaches a maximum, there is an electromagnetic field. Then there is the corresponding magnetic field on the second coil, and the device begins to work. Such scheme allows to control electric load without the actual physical connection or special sensors. Magnetic amplifiers usually have unlimited service life as they have no moving parts which can wear out. For the same reason they are irresponsive to vibration and blows and can be used in any conditions. Thanks to these advantages they are often used in production of the industrial equipment.
Shortcomings of magnetic amplifiers
The magnetic amplifier has some shortcomings. The size is one of the biggest problems of such elements. Modern transistors can perform the same function, taking much less places. Magnetic amplifiers are also not so effective as the modern solid-state transistors used for reduction of power losses. The coefficient of strengthening of the magnetic amplifier is also much lower in comparison with semiconductor elements. All this pushes producers to replacement of magnetic amplifiers by their solid-state analogs. Nevertheless there can shortly be new types of magnetics and on their basis the next generation of these devices will appear.