The transformer concludes core and coils with there are two or more coil windings, wherein the power supply is called the primary coil winding, called the rest of the secondary coil winding. Now we can buy them from copper equipment manufacture if you want to.
It can convert AC voltage, current and impedance. The simplest core transformer consists of a core made of a soft magnetic material and set in the core of the two turns of the coil unequal role of core is to strengthen the magnetic coupling between the two coils. In order to reduce the eddy current and hysteresis losses in the iron, laminated iron core made of painted steel sheet made; no electrical connection between the two coils, the coils by the insulated copper wire (or aluminum) wound. A coil connected to AC power called the primary coil (or primary coil), other coil called a secondary coil connected to electrical (or secondary coil). It is different from the equipment from copper melting furnace wholesale. The transformer is actually very complicated, inevitably copper loss (resistance heating coil), iron loss (core heat) and magnetic flux leakage (air-closed magnetic flux lines), etc., in order to simplify the discussion here only ideal transformer. Ideal conditions for the establishment of the transformer is: Ignore the leakage flux, ignoring the resistance the primary and secondary coils, ignoring core loss, ignoring the no-load current (open primary coil secondary coil current in the coil).
Such power transformer at full load runtime (secondary coil output rated power) is close to an ideal transformer case. Of course, it needs the help of customized graphite mould to some extent.