please try to make your answers brief and detailed
control force or torque is apple in an instrument to oppose to deflection torque of the pointer. The controlling torque bring the pointer back to zero postion and it avoid the from exceedin its reading.... The controlling torque is produce with the use of *spring (spring control) by Attaching it to the spindle so that when there is a deflection the spring will oppose d deflection which is directly proportional to the deflection force. *load(gravity contorl) which will provid a controling force that is proportional to the deflecting torque. Hope this little info helps?
spring control depends on energy to push against a spring to move and indicator, such as a speedometer. Gravity control uses the force of gravity to measure things like what is level or how much an angle is.