Transformer Operation

—If two separate coils of wire be wound on an iron bar, and a direct current be pa ed through one coil, no effect is produced in the other coil except at the moment of turning on the current, but if an alternating current be used instead, a current is at once _produced and maintained in the second coil. ya very simple law the pre ure or voltage of the two coils is approximately in proportion to the number of turns in each. Thus, if the primary coil be supplied with current of 1,000 volts, and the secondary coil has one-tenth as many turns, the pre ure in the secondary will be approx i; mately 100 volts. By the proper proportion of the primary and secondary coils, the voltage may be raised to any pre ure which can be safely transmitted.