Since the 1990's cathodic protection of stainless steels has been used for protecting larger objects such as pumps coolers filters and more expensive piping with larger diameter. This paper describes controlled cathodic protection with sacrificial anodes. In order to control the protection current static components such as resistors and diodes are used. Parameters such as flow temperature scaling factor salinity and biological activity constantly change. Corrodium has developed circuit boards controlled with active components such as transistors. These circuit boards do not have any threshold Voltage or internal resistance. This means that the anodes can deliver full current capacity when required. The circuit is powered by the sacrificial anode itself; no batteries or power supplies are used. The lifetime of the anodes is 5-30 years depending on design specifications. Two types of circuits have been developed and successfully installed worldwide:- Pulsing circuits. For protection of stainless steels and other CRA's. If unprotected the potential is -100 to + 500 mV Ag/AgCl. The CP system causes a pulse between -200 and -900 mV Ag/AgCl (frequency 001 Hz). This gives full protection avoids over protection and works as anti-biofilm due to alternating pH value.- Controlled potential (set value normally -900 mV Ag/AgCl). This is for protection of steel and other alloys against galvanic corrosion combined with optimal protection of the CRA's. For seawater asnd brackish water Zinc or Aluminium anodes are used for fresh water (e.g. river water) Magnesium anodes are used. Several applications will be demonstrated: Protection of stainless steel 316L sandbed filters in fresh water.Protection of Ammonia-seawater coolers pipe side (duplex SS 2205).Protection of gas-seawater coolers shell side (Hastelloy C276/cladded steel).Protection of seawater liftpump caissons (steel) and the duplex SS pumps.Protection of duplex SS seawater pumps (inlet and outlet diameter 2 m).Saving cost by usage of 316L+CP instead of super duplex SS.Inside seawater piping protection (D= 300-1000 mm).Outside protection of martensitic stainless steel subsea pipeline.