A typical transformer consists of two coils of insulated wire wound around an iron-containing core. One coil is connected to the source of electricity, while the other to the device being powered with the transformed electricity. The ratio of the number of turns the coils are wound to the core depends on how much transformation is needed.
Essentially, conduction through the iron-containing core is needed to transform high voltage to low voltage electricity or vice versa. Conduction is the transferring of electricity (movement of electrically charged particles) from one object to another through a solid transmission medium. In the case of a transformer, the core functions as the conductor, although transformation is influenced by the magnetic field created by the setup.
The problem with this setup is that there’s a risk of electrocution when installing the transformer, since one coil must be connected with the source of electricity. It’s generally risky when you only need to transform electricity to measure the electric current flowing through a transmission. Fortunately, there is another type of transformer that doesn’t need to make contact with the source just to measure electric current—current transformer.
A current transformer consists of a circular core installed around a wire (source of electricity). Through the magnetic field created by the electricity flowing through the transmission line, electricity can be transferred at a much safer voltage to the core down to current measuring device. Anyone who wants to measure current more safely should consider using a current transformer.