Instead of using plain DC current for electrochemical processes, a pulsating current is employed, which has numerous advantages. These are available in two categories:

• The pulse frequency is derived from the mains frequency of 50 Hz. Output ON and OFF times are integer multiples of 20 milliseconds. These rectifiers are used for anodizing applications and are available in the high-power range.
  
  
• The pulse frequency is up to 10 kHz. The current pulses can be programmed in different configurations such as forward, reverse, pulse-on-pulse, etc. These are used for precious metal plating and other specialized applications.