Articles in this category are about converting electric energy from one impedance, phase or frequency (including direct current) to another. But the energy form remain in the same domain and the focus is on energy conversion – not signal conversion or measurement (like Current-to-voltage converter or Voltage-to-current converter).
Example: Articles in this category are about electrical power conversion (impedance change). E.g. if a switched-mode power supply is loaded by 10 A at 5 V (50 W) and it is fed with 1 A and 51 V (51 W).