An electro-hydraulic actuator is an actuator that operates a valve via pressured hydraulic fluid however, its main source of energy is solely electric power. ​

The supplied electric power is used to energize a motor that runs a hydraulic pump which then supplies the pressurized fluid to operate a hydraulic actuator for the control valve. ​

The complete system is self-contained which eliminates the need for separated hydraulic power unit, simplifying the system construction and improving safety and reliability. 

A self-contained electro-hydraulic actuator can be used with linear and rotary valves. It has been used with butterfly-valves and gate valves for various industrial applications.