Переведите текст буду : the transformer a transformer cannot be called a machine for it has no moving parts. we know the transformer to be an apparatus designed for changing voltages and currents by means of magnetic induction. a two-winding transformer is consist of two coils so arranged that the magnetic lines of force of one coil pass through the other. transformers is generally used only with alternating current. the alternating current in one coil induces an e.m.f. in the other one because of the alternations in the value of the current in the first coil. in order to strengthen the magnetic field passing through the coils of a transformer, a closed core of iron is generally used. the iron provides a good path for the magnetic lines of force and nearly all the lines of force from one coil pass through the other. an ideal transformer has no load losses. it means that all the lines of force of one coil pass through the other, and vice versa. however, the ordinary transformer is supposed to have no load losses. the coil on which the current is impressed on the input side of the transformer is called the primary, while the one from which the induced current is obtained on the output side is called the secondary. in case the secondary has more turns than the primary, the output voltage is larger than the input voltage and the transformer is called a step – up when transformer. the secondary has fewer turns than the primary the transformer is called a step-down transformer. if the same number of magnetic lines of force pass through two-coils, the ration of the e.m.f. induced in the two coils is proportional to the ratio of the number of turns in the two coils. in the transformer this means that the e.m.f. in the secondary is to e.m.f. in the primary as the number of turns in the secondary is to the number of turns the primary.