Transformers

Transformers step up or step down AC electricity from the first (input)  to the secondary (output). The primary and secondary windings are connected to their own coils, which are both wrapped around a column with a hollow air core or presumably Associate in Nursing cast-iron core. The coils from the two sides are interspersed around the core. Through electromagnetic operating, the voltage increases or decreases as per the magnitude relation of the quantity of coils.

Inverters

Inverters are used to convert DC to AC electricity. A simple design builds on the transformer model by modifying DC on the primary side to mimic AC. The inverter rapidly flips a switch to alternate the direction of a DC current on the primary side, simulating AC current. The secondary side of the inverter sees AC current and produces genuine AC out its side.

Converters

Converters are designed to convert AC to DC. Almost all the electronic devices will need a converter. They are also used to detect amplitude modulated radio signals as well as supplying polarized voltage for welding. Converters can be used for DC-DC conversion.

There are three main kinds of converters, namely analog-to-digital converter (ADC), digital-to-analog converter (DAC), digital-to-digital converter (DDC).