Which component is typically absent in a constant voltage CP rectifier?

In a constant voltage cathodic protection (CP) rectifier, the component that is typically absent is the transistor.

Constant voltage rectifiers primarily utilize transformers and rectifying elements to convert alternating current (AC) input into direct current (DC) output while maintaining a constant voltage level. The transformer steps down or isolates the voltage to a usable level, while the rectifying element (usually diodes) converts the AC to DC.

Transistors, on the other hand, are used in more complex systems, such as switching power supplies or variable voltage rectifiers, where they regulate power flow rather than just converting voltage. Since the aim of a constant voltage rectifier is to deliver a stable voltage output without the need for active regulation provided by transistors, it typically operates effectively with just transformers and rectifiers. Thus, the absence of transistors is characteristic of this type of rectifier.