For application to medium- and high-voltage circuit breakers, the control device makes it possible to actuate opening of the circuit breakers used in the medium- and high-voltage networks very quickly. The spring used in the control device is a spring of the composite type, having a curved C- or Ω-shape. The spring has a stationary first end and a movable second end that is pivotally connected to the end of a lever device, that is itself constrained to rotate with the drive shaft of the control device.