Answer:
a pneumatic or electric power
Explanation:
The primary energy source for the controller in a typical control system is either "a pneumatic or electric power."
This is because a typical control system has majorly four elements which include the following:
1. Sensor: this calculates the controlled variable
2. Controller: this receives and process inputs from the sensor to the controlled device as output
3. Controlled device: this tweak the controlled variable
4. Source of energy: this is the energy used to power the control system. It could be a pneumatic or electric power
